FINAL NETWORK DESIGN - VARIANT ADDENDUMjorcutt/1101-00001_FND_Addendum_Va… · Final Network Design - Variant Addendum FINAL NETWORK DESIGN - VARIANT ADDENDUM Version 1-01 Document

Final Network Design - Variant Addendum

FINAL NETWORK DESIGN - VARIANT ADDENDUM

Version 1-01 Document Control Number 1101-00001 2009-02-24

Consortium for Ocean Leadership 1201 New York Ave NW, 4th Floor, Washington DC 20005 www.OceanLeadership.org in Cooperation with University of California, San Diego University of Washington Woods Hole Oceanographic Institution Oregon State University Scripps Institution of Oceanography


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Document Control Sheet

Version Date Description Originator

1-00 Feb 24, 2009 Initial Variant Release T. Cowles, S. Banahan, A. Ferlaino, E. Griffin

1-01 Feb 24, 2009 Index Update A. Ferlaino, S. Banahan


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Table of Contents: Document Control Sheet ............................................................................................................................. i Table of Figures: ...........................................................................................................................................iii Table of Tables: ........................................................................................................................................... iv Preamble....................................................................................................................................................... v Preamble....................................................................................................................................................... v 1 Introduction ............................................................................................................................................1

1.1 Background ......................................................................................................................................1 1.2 Overview of the Proposed Changes to the OOI Final Network Design ...........................................2 1.3 Scientific Basis for the OOI Design..................................................................................................3

1.3.1 Capability of the OOI Network to address the specific science themes of climate, carbon, acidification, ecosystem health ..............................................................................................................5

1.4 Summary of Science Losses and Gains in the Variant and Variant Up Scope Designs .................7 1.4.1 Losses .....................................................................................................................................7 1.4.2 Gains .......................................................................................................................................7

2 OOI Network Variant Design .................................................................................................................9 2.1 Variant Requirements ....................................................................................................................10

2.1.1 Level 2 Requirements ...........................................................................................................10 2.1.2 Level 3 (L3) System Technical Requirements ......................................................................10

2.2 Cyberinfrastructure – Variant Description......................................................................................10 2.3 Coastal and Global Scale Nodes – Variant Description ................................................................11

2.3.1 Introduction............................................................................................................................11 2.3.2 Global Scale Nodes...............................................................................................................12 2.3.3 Coastal Scale Nodes.............................................................................................................16 2.3.4 Shore-Side Facilities .............................................................................................................31

2.4 Regional Scale Nodes – Variant Description.................................................................................32 3 VariantUpScope...................................................................................................................................35

3.1 Coastal Scale Nodes – VariantUpScope Description ....................................................................35 3.1.1 Endurance Array Washington (WA) Line VariantUpScope Description................................35 3.1.2 Endurance Array Washington Line - VariantUpScope Core Sensors and Platforms ...........37 3.1.3 Endurance Array Washington Line VariantUpScope Technical Approach ...........................37

3.2 Regional Scaled Nodes – VariantUpScope Description ................................................................39 4 Comparison of Network Configurations ...............................................................................................39

4.1 Science Gains and Losses in the Variant and VariantUpScope designs ......................................39 4.1.1 Gains .....................................................................................................................................39 4.1.2 Justification for a cabled Endurance Array Washington Line................................................39 4.1.3 Losses ...................................................................................................................................39

4.2 Sensing capability of the OOI under Variant and VariantUpScope ...............................................39 4.3 Future Opportunities ......................................................................................................................39 4.4 Summary........................................................................................................................................39

5 References...........................................................................................................................................39


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Table of Figures:

Figure 2-1. Location map of the OOI Variant marine infrastructure.............................................................9 Figure 2-2. High-level functional block diagram of the CGSN ...................................................................12 Figure 2-3. Schematic of the Global Array design. Includes (foreground) a paired surface mooring and profiler mooring, (background) two taut subsurface, flanking moorings, and (dashed lines) three gliders. The moorings define a triangular region 50 km on a side (inset); gliders patrol along the axis of the triangle.........................................................................................................................................................13 Figure 2-4. Plan view map of the Endurance Array, including the Washington Line and Oregon Line.....22 Figure 2-5 . Schematic diagram of the Endurance Array Washington Line. Shown are surface-mooring/profiler pairs at offshore, shelf and inshore sites, benthic multifunction nodes (MFN), Gliders will patrol the region, with one offshore line coincident with the moored array.................................................26 Figure 2-6. Endurance Array Washington Line 500 m and 80 m Surface Mooring. ..................................27 Figure 2-7. Endurance Array Washington Line 25m Surface Mooring. .....................................................28 Figure 2-8. Endurance Array Washington Line Offshore Profiling Mooring...............................................30 Figure 2-9. FDR Baseline that includes the Warrenton and Pacific City shore stations, connection to the Cyber-POP at Portland Oregon, the sub-sea cable segments, and the nine Primary Nodes. ...................32 Figure 2-10. The Variant (labeled Option 1) showing the loss of cabled infrastructure at the Blanco and Subduction Zone Sites, and loss of all science sensors at the Mid-Plate Site. Also lost are the Warrenton shore station and associated backhaul. The three moorings of the reinstated Endurance Array Washington Line off Grays Harbor are also shown. ...................................................................................32 Figure 2-11. The high-level block diagram for the Variant (Option 1) showing the RSN Infrastructure and the Primary and Secondary Infrastructure associated with the CSN Endurance Extension Line. The RSN and CSN share Primary Node 1C. Components shown in red are those removed from the FDR Baseline design..........................................................................................................................................................34 Figure 3-1. Plan view map of the VariantUpScope Endurance Array, including the Washington Line and Oregon Line. ...............................................................................................................................................36 Figure 3-2. Schematic diagram of the Endurance Array VariantUpScope, representative for both Endurance Washington Line and Endurance Oregon Line. .......................................................................38 Figure 3-3. High-level functional block diagram of the VariantUpScope CGSN........................................39 Figure 3-4. The proposed VariantUpScope (labeled Option 2) showing loss of cabled infrastructure at the Blanco Transform Fault and loss of all science sensors at the Mid-Plate Site. In this scenario, a full capability expansion port on the Mid-Plate Primary Node 5A is used to support the backbone cable to the Subduction Primary Node 4A. Similar to the Variant, no science is supported at Primary Node 4A (water depth ~ 3000 m). Node 4A supports an extension cable for Coastal Scale cabled Nodes at 500 m (Primary Node 4B), 150 m (Primary Node 4C), and 80 m (Low Voltage Node 4C). ..................................39 Figure 3-5. The high-level block diagram for the VariantUpScope (labeled Option 2) showing the RSN Infrastructure and the Primary and Secondary Infrastructure associated with the Endurance Array Lines off Oregon and Washington. Components shown in red are those removed from the 2008 FDR Baseline design..........................................................................................................................................................39 Figure 4-1. Patterns of sea-surface CO2 (left, Gruber et al. 1996) and vertically-integrated CO2 inventory (right, Sabine et al. 2004). Note the distinct differences between the inventories in the Northern and Southern Atlantic, in contrast to the relative similarities in surface values. ................................................39 Figure 4-2. Schematic diagram of the components linking a primary node at Hydrate Ridge with the Endurance Line off Oregon. A detailed description of this configuration can be found in Section 4.3.3.7 of the FND. This configuration would be replicated at 25, 80, and 500 m off Washington under VariantUpScope design. .............................................................................................................................39 Figure 4-3. OOI core sensor types by discipline. .......................................................................................39 Figure 4-4. a) FND sensors by discipline, b) Variant sensors by discipline, c) Percent change by discipline from FND Baseline to Variant. ....................................................................................................39


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Table of Tables:

Table 1-1. Summary of marine network configurations discussed in this addendum..................................2 Table 2-1. Global Arrays core sensor and platform summary ...................................................................14 Table 2-2. Pioneer Array core sensor and platform summary ...................................................................16 Table 2-3. Endurance Oregon Line core sensor and platform summary...................................................18 Table 2-4. Platform locations and depths for the Endurance Array Washington Line. ..............................23 Table 2-5. Endurance Array Washington Line core sensor and platform summary. .................................23 Table 2-6. RSN infrastructure and sensors remaining (black) and removed (in red) in the Variant..........33 Table 3-1. Platform locations and depths for the Endurance Array Washington Line. ..............................37 Table 4-1. Power and Bandwidth Expandability Examples .......................................................................39


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Preamble

This addendum to the OOI Final Network Design document (OOI Document Control Number 1101-00001, November 2008) will address the scientific and technical gains and losses of an alternative network design, hereafter designated as the Variant, relative to the November 2008 Final Network Design, hereafter designated as the FND Baseline. The cost, schedule, work breakdown structure, and risk elements of the Variant have been quantified for detailed comparison with the matching documents from the Final Design Review in November 2008. This addendum also provides a description, with estimated costs, of an upscope option to the Variant, hereafter designated as the VariantUpScope. Finally, the content (and interpretability) of this addendum relies on familiarity with the parent Final Network Design document (referenced above).

This addendum has been structured in five sections. The first section provides a brief summary of the evolution of the OOI network design as well as a brief executive summary of the technical and scientific differences between the FND Baseline, the Variant, and the VariantUpScope. The second and third sections of the addendum contain the detailed technical descriptions of the specific design changes to the Global, Coastal, and Regional components that are contained within the Variant and the VariantUpScope, respectively. In the fourth section, the scientific differences between these network designs are evaluated. The last section is the list of references.


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1 Introduction

1.1 Background

The review of the Ocean Observatories Initiative (OOI) Final Network Design (FND) was held in November 2008. The Cost and Schedule Review took place on November 6-7; the Technical and Programmatic Review on November 12-14, 2008. The OOI Project Team prepared a comprehensive suite of design and management documents (~160 technical documents and 23 sets of technical drawings) for evaluation by the 24-member NSF Final Design Review (FDR) Panel.

The FDR Panel report titled, National Science Foundation Panel Report on the Final Design Review of the Ocean Observatories Initiative (OOI) is posted on the Consortium for Ocean Leadership – OOI website: http://oceanleadership.org/ocean_observing. The overall conclusion of the report is exceedingly positive. Among the findings of this review:

“The Ocean Observatories Initiative (OOI) continues to demonstrate the potential for significant broader impacts and the intellectual merits are outstanding.”

“The OOI scientific goals, requirements, and interfaces are mature and the designs are consistent with design requirements. The overall design maturity is adequate to start construction on the proposed schedule, July 2010.”

“The engineering and technical plans are sufficiently mature to produce solid cost estimates, schedules, and identification of risk factors.”

The FDR Panel also recommended increasing the total construction cost contingency (~25 % at FDR) to 30% and the NSF concurred. The OOI Project Team then revised the FND Baseline to conform to this guidance; the FND Baseline construction cost including 30% contingency is $422M. On January 22, 2009, the NSF’s Division of Ocean Sciences (OCE) informed the OOI Project Team of the NSF’s decision to examine an alternative to the Final Network Design (i.e., FND Baseline ) within a $400M construction cost cap, including 30% contingency. The NSF’s proposed changes to the FND Baseline are intended to enhance the OOI’s potential for research advances in the areas of carbon cycling and ocean acidification, climate change, and health of coastal ecosystems. The OOI Project Team was directed to provide design, cost, and schedule documentation for the NSF proposed adjustments, referred to as the Variant network design, and submit this design documentation to a science, cost and schedule review in early March 2009. In the interest of preserving aspects of the expandability and transformative capability of the FND baseline, the OOI Project Team has developed an upscope option to the Variant design.

The purpose of this addendum is to describe the Variant design, the science motivation for the design modifications, the capabilities that this modified design will provide, and compare these capabilities with those provided by the FND Baseline. A description of the VariantUpScope is also included. The short timeframe for preparing the technical documentation for the science and cost/schedule reviews taking place March 2-4 did not allow sufficient time to provide a fully vetted document package for the VariantUpScope.

This addendum will reference sections in the OOI Final Network Design (DCN 1101-00000). The OOI FND provides a detailed technical description of the networked infrastructure and sensor grid that will collect ocean and seafloor data at high sampling rates over years to decades. The OOI will permit researchers to make simultaneous, interdisciplinary measurements to investigate a spectrum of phenomena including episodic, short-lived events (meteorological, physical, biological, chemical, tectonic, volcanic), and more subtle, longer-term changes and emergent phenomena in ocean systems (circulation patterns, climate change, carbon cycling, ocean acidity, and trends in ecosystem health).


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1.2 Overview of the Proposed Changes to the OOI Final Network Design

The NSF has proposed enhancing the observing capabilities of the Endurance Array with the addition of the Grays Harbor, Washington Line and providing increased global coverage with the addition of the Global site in the Argentine Basin. The Endurance Array Washington Line and the Argentine Basin global site were both part of the OOI Conceptual Network Design (March 2007) but had been eliminated prior to the Preliminary Network Design Review (December 2007) due to fiscal constraints. To accommodate these enhancements to the Global and Coastal assets of the OOI within a $400M cost baseline in the Variant, the NSF directed the elimination of seafloor cabling, infrastructure, and instrumentation at the Blanco Transform Fault (Node 2A) and the Subduction Zone (Node 4A and 4B), and the elimination of science capability at the Mid-plate (Node 5A). Table 1-1 summarizes the existing FND infrastructure and the NSF proposed modifications.

Table 1-1. Summary of marine network configurations discussed in this addendum.

Final Network Design Baseline Variant Network Design VariantUpScope Design

Global Scale North Pacific

Station Papa North Pacific Station Papa

North Pacific Station Papa

Southern Ocean Pacific – 55oS



North Atlantic Irminger Sea



South Atlantic Argentine Basin

South Atlantic Argentine Basin

Coastal Scale Pioneer Array

Mid-Atlantic Bight Pioneer Array

Mid-Atlantic Bight Pioneer Array

Mid-Atlantic Bight Endurance Array – OR

3 moorings, 2 cabled to Regional Scale

Endurance Array – OR 3 moorings, 2 cabled to

Regional Scale

Endurance Array – OR 3 moorings, 2 cabled to

Regional Scale

Endurance Array – WA 3 moorings, no cable

Endurance Array – WA 3 moorings, 2 cabled to

Regional Scale Regional Scale (cabled)

Axial Seamount, seafloor array of instruments, with water column moorings

Axial Seamount, seafloor array of instruments,

with water column moorings

Axial Seamount, seafloor array of instruments,

with water column moorings

Hydrate Ridge, seafloor array of instruments, with water column moorings



Blanco fracture zone, seafloor array of

instruments

Mid-Plate, seafloor array of instruments

Mid-Plate node, no instruments

Mid-Plate node, no instruments

Subduction Zone, seafloor array of

instruments Subduction Zone node,

no instruments


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1.3 Scientific Basis for the OOI Design

Throughout its development, the vision underpinning the OOI Network was to provide a state-of-the-art observational infrastructure for the ocean sciences community that would open new paths for observation and experimentation over the next 20-30 years. These new opportunities would span a broad range of ocean research domains and disciplines. The design goals reflecting the ocean science community’s vision for the OOI were set out in the National Research Council report “Enabling Ocean Research in the 21st Century: Implementation of a Network of Ocean Observatories” (2003). The design goals established in this and many subsequent reports remain those required to address broad community science goals: (1) continuous observations at time scales of seconds to decades; (2) spatial measurements from millimeter to kilometers; (3) the ability to collect data during storms and other severe conditions; (4) two-way data transmission and remote instrument control; (5) power delivery to sensors between the sea surface and the seafloor; (6) standard sensor interfaces, (7) AUV docks for data download and battery recharge; (8) access to facilities to deploy, maintain, and calibrate sensors; (9) an effective data management system that provides open access to all; and (10) an engaging and effective education and outreach program that increases ocean literacy.

The OOI Network is to be constructed with funds from the NSF Major Research Equipment and Facility construction (MREFC) appropriation. To be eligible for MREFC consideration, the NSF Large Facilities Manual (May 2007) states that a candidate project “…should represent an outstanding opportunity to enable research and innovation, as well as education and broader societal impacts. Each project should offer the possibility of transformative knowledge and the potential to shift existing paradigms in scientific understanding, engineering processes and/or infrastructure technology.”

Since the development of the Conceptual Network Design (CND), the OOI Project Team has used extensive community input, along with NSF guidance, to balance these ambitious design goals with fiscal realities. The goal has been, and remains, to provide the infrastructure to fulfill as many user requirements as possible. The “PDR era” OOI advisory committee articulated guiding principles for decision-making, i.e., the importance of supplying power and communications capacity substantially exceeding traditional ocean observing platforms; an emphasis on developing fewer, but more highly capable systems, rather than numerous systems with traditional capability; using a mixed portfolio of fixed and mobile assets to appropriately address science goals; the importance of maintaining the multiscale nature of the overall facility, and integrating across the coastal, regional, and global scales; the recognition that the OOI is a research platform that will enable future experiments and capabilities beyond those included in the initial configuration; and enabling exciting science with the initial core suite of sensors.

The OOI is unique in its integration of multi-disciplinary sensing capabilities with a robust and expandable infrastructure. It will employ high-capacity platforms and advanced instrumentation, high-speed fiber-optic connectivity and always-on power, to provide a deeply interconnected, interactive architecture that will support a sophisticated web of sensors, analysis and modeling cyberinfrastrcture, as well as virtual communities of users and observers. The OOI is designed to provide these key features for ocean science:

• Persistence: Designed for long-term (greater than 25-year) operation, support, and data access

• Geographic Range: Long-term occupations of specific volumes in distinct ocean basins to adaptively observe ocean processes on multiple scales

• Mobility/Portability: Able to go where the action is and the science demands

• Control/Adaptability: Responsive to commands, addressing real-time needs as revealed by event detection, data analysis and data assimilation into models

• System Interoperability: Common approaches for data exchange and for meeting science user needs

• Intercommunication: All components of the observatory linked by a common cyberinfrastructure


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• Power/Bandwidth: Experiments, instrumentation, and observing capacity freed from power and data limits

• Sensor Capability: Increased spatial, temporal, and measurement resolution

• Community: Shared access for all assures the construction of collaborative interactions within and across all the thematic areas of the OOI

The FDR Baseline network design and core suite of sensors are tightly linked to the long-standing, overarching science themes for the observing initiative (also discussed in section 2.2 Science Themes, page 7 in the OOI Final Network Design). These themes are briefly summarized in the following list:

Ocean-Atmosphere Exchange

Includes questions addressing quantification of air-sea exchange of energy and mass during high winds and severe storms; improving climate change models and storm forecasting

Climate Variability, Ocean Circulation, and Ecosystems

Including questions of the ocean’s role in the global carbon cycle; impacts of climate change on ocean circulation, weather patterns, ocean acidification and biochemical processes, food webs, and ecosystem structure.

Turbulent Mixing and Biophysical Interactions

Understanding and quantifying mixing events and the impacts on exchange of energy, heat, mass; effects on plankton growth and community structure; cycling of material in the water column and transport of material (including carbon) to the deep ocean.

Coastal Ocean Dynamics and Ecosystems

Including questions addressing the role of coastal margins in the global carbon cycle; interactions of open ocean, terrestrial, and atmospheric forcing; climate variability and coastal ocean ecology; dynamics of episodic events (e.g., harmful algal blooms, hypoxia); forecasting and strategies for managing coastal systems in a changing climate.

Fluid-Rock Interactions and the Subseafloor Biosphere

Includes research addressing questions of the role of the ocean crust in the global budgets of material (including carbon) and heat; the role of thermal circulation and vent fluid chemistry in the ecology of vent communities, methane gas and hydrate formation; and the role of transient events on deep ocean physical and biochemical processes.

Plate-scale, Ocean Geodynamics

Includes questions of the role of short-term, transient events (e.g., earthquakes, volcanic eruptions, tsunamis, and slope failures) on deep ocean hydrothermal and biological systems; and impacts on continental shelf and coastal systems.

These themes are interdisciplinary and dynamically linked with respect to the physical, biological, geological, and chemical processes encompassed in each theme. The OOI network design reflects these linkages. This was accomplished through an iterative process of: examining high priority science questions representative of the OOI science themes; linking those questions to the observations required to address them; assessing the technologies (instrumentation and sensors) needed to obtain those observations at the appropriate level of precision, and evaluating the environments best suited to making those observations. Some example science questions (from the OOI Science Plan (January 2005) and other NSF science planning reports) were traced within the Preliminary Network Design and displayed in the format of science traceability matrices in the OOI Science Prospectus (October 2007). These traceability matrices then served as the basis for deriving the formal science requirements which reside and are tracked in the OOI Requirements Repository (DOORS database).


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1.3.1 Capability of the OOI Network to address the specific science themes of climate, carbon, acidification, ecosystem health

Ocean ecosystem health, climate change, carbon cycling and ocean acidification are interrelated, linked by processes and impacts within the ocean, and through the ocean’s interactions with the atmosphere and land. Whether located in the open ocean, at the seafloor, or along coastlines, healthy marine ecosystems exist as a function of the physical setting and a balance of energy inputs and food web dynamics. This balance is being altered by changing climate, with uncertain consequences within different ocean habitats. At all spatial scales, the ability of the ocean to absorb greenhouse gases is being altered by changes in upper-ocean stratification. Climate change is implicated in the increased variability in atmospheric forcing over the sea surface, yet the spatial and temporal distribution of that increased variability, and the ocean response to that forcing, cannot be quantified as yet due to insufficient data. Furthermore, the consequences of 150 years of increased CO2 absorption by the ocean are being expressed in ecosystem responses to lower pH. The aragonite and calcite saturation horizons have shoaled towards the surface of the oceans due to the penetration of anthropogenic CO2 into the oceans. Healthy marine ecosystems are now being exposed to waters made more acidic by the uptake of anthropogenic carbon dioxide along continental boundaries, setting the stage for fundamental changes in the functioning of these ecosystems. Changes in wind forcing, surface heating, and freshwater input brought on by climate change are altering the rhythms of marine ecosystems. These include north-south shifts in wind patterns, trends and new maxima in surface temperatures, changes in the timing of the seasons, increases in extreme storm events, and shifts in the linkage of mid-latitude coastal waters to high-latitude sources of freshwater.

Diverse mixing processes redistribute heat, energy, nutrients, water properties, and elements of the marine ecosystem, both vertically and horizontally. Quantifying and understanding the processes that govern the three-dimensional structures and variability, and mixing processes found at fronts and in association with mesoscale structures such as eddies, is essential as a basis for understanding the dynamics of the ocean and its ecosystem. Thus, it has long been a design imperative for the OOI infrastructure to resolve climate change parameters (and the associated physical and biogeochemical processes) across appropriate time scales (minutes to decades), at multiple spatial scales (centimeters to 1000s of kilometers), from the air-sea interface to the seafloor, and link those measurements through an innovative and transparent cyberinfrastructure. Additional design imperatives (as discussed above) complemented this essential need for temporal and spatial coverage of climate parameters. The choice of observation nodes and sensor types, as well as the initial sensor distribution across the infrastructure, all flow from these design imperatives. The technical aspects of this design are fully described in the parent FND document (OOI FND, DCN 1101-00000) of this addendum.

1.3.1.1 Climate Change

Climate change will result in a broad range of shifts in ocean conditions, some of which are already measurable and others that are anticipated. Increased heating of the upper ocean as well as freshening of the upper ocean in key high latitude locations influences stratification and reduces the connection of surface waters, in contact with the atmosphere, with deeper waters below. This, in turn, may change the vertical distributions of dissolved oxygen, carbon dioxide and nutrients, all of which influence marine ecosystems from the surface to the seafloor. Surface wind speeds are increasing over the ocean, as is evaporation. Climate change may further alter large-scale winds through northward shifts in the major atmospheric jets and changes in the intensity of land-sea temperature differences and hence alongshore, upwelling favorable winds. Climate change also results in altered seasonality in the stratification of the open ocean and in variability of winds and river runoff, shifting, on decadal time scales, the conditions that ocean ecosystems have adapted to over millennia. Climate change also influences the rate and character of the flux of carbon to the seafloor, altering the rates of biogeochemical recycling from the deep ocean to the surface ocean and the atmosphere. On the basin and global scale, climate change has the potential to alter the large scale, thermohaline circulation that links all the basins as well as the surface to the interior ocean.


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As noted above, the OOI infrastructure is designed to measure changes in atmospheric and ocean conditions in specific regions, linking high latitude processes to productive coastal ecosystems, while simultaneously tracking the responses of water column and seafloor processes to variability in climate forcing. In addition, the OOI will document the temporal variability of the cross-shelf processes that link those systems to the open ocean in two distinct shelf-slope regions (Pacific Northwest and the Middle Atlantic Bight). The observing infrastructure that has evolved from Conceptual design to Final design permits resolution of these coupled processes across a broad range of scales.

1.3.1.2 Carbon Cycling and Ocean Acidification

Increased ocean acidification is part of the ocean-atmosphere carbon cycle. Anthropogenic CO2 has penetrated the upper layers of the world’s oceans and altered the depth of dissolution of aragonite and calcite (Feely et al., 2004). Recent evidence shows acidic waters being upwelled onto the PNW continental shelf (Feely et al., 2008). The OOI infrastructure includes platforms and sensors targeted at the carbon cycle and ocean acidification. These include physical (temperature, salinity, currents, suspended particles), bio- and geochemical (nutrients, dissolved oxygen, carbon dioxide, hydrogen sulfide, pH), and biological sensors (chlorophyll, zooplankton). The OOI infrastructure will monitor changes in water-column pH and pCO2 in response to changes in atmospheric CO2, but also detect changes in upper-ocean stratification and winds that modulate the degree to which acidic water is exposed to the euphotic zone. These observations will be supported across the spatial scales of the OOI infrastructure, with appropriate sensor suites on all the moorings at the Global, Regional, and Coastal nodes in all the network designs discussed in this addendum.

1.3.1.3 Health of Coastal Ecosystems

The OOI coastal arrays (Endurance and Pioneer) include platforms and sensors targeted to sample the key elements of marine ecosystems from physics (currents, stratification,), through biogeochemistry (nutrients, dissolved oxygen, suspended particles) to biology (chlorophyll, zooplankton). The platforms and sensors cover the entire water column and extend from the inner shelf out to deeper waters. The addition of a Washington mooring line to the Pacific Northwest Endurance Array (PNW) will allow the study of the influence of alongshore advection and differing upper-ocean stratification on ecosystem processes. Specifically, alongshore advection links formation regions for harmful algal blooms to places where coastal ecosystems are adversely affected (Trainer et al., 2002, 2009). These threats to ecosystem health are linked to climate variability, as indicated by recent observations along the Pacific coast showing an increase in paralytic shellfish poisoning (PSP) events along the PNW coast during ENSO conditions (see http://bioloc.oce.orst.edu/strutton/hab_research.html).

Alongshore currents can carry harmful algae long distances to inoculate large stretches of shoreline. Increasing low-oxygen “dead zones” observed in the Pacific Northwest are influenced by not only changes in upwelled source waters and upwelling winds, but also by the amount of organic matter produced at the surface in phytoplankton blooms (Chan et al., 2005, Barth et al., 2007). In the case of the PNW, the amount and location of phytoplankton productivity is related to upper-ocean stratification and nutrient sources, although other low-oxygen zones around the U.S. coastline may be influenced by additional factors. The PNW case will be able to be quantified with the Endurance Array. Additional shelf-slope habitats around the U.S. can be examined with OOI infrastructure through the relocation of the Pioneer Array after the first five years of science operations (the relocation process is discussed in the OOI Operations and Maintenance Plan DCN 1010-00000).


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1.4 Summary of Science Losses and Gains in the Variant and Variant Up Scope Designs

1.4.1 Losses Explicit in all OOI planning documents is the unique character of the Juan de Fuca Plate in providing a range of geodynamical sites on a single tectonic plate, within a manageable spatial domain, and abutting the US Exclusive Economic Zone (EEZ). This collection of features also sits within the basin-scale to coastal-scale observing elements of the OOI, as represented by the Global Array at Station Papa in the Gulf of Alaska and the Endurance Array over the PNW shelf and slope. Thus the instrumented nodes over the Juan de Fuca plate provide key intermediate observation points for the OOI’s spatial resolution of ocean processes within the Northeast Pacific Ocean.

The cabled Regional Scale Nodes (RSN) (as described in the OOI Final Network Design) will provide unique capabilities for real-time observations and experimentation in the Northeast Pacific. The RSN will be capable of far greater bandwidth (Gbs-1) and furnish far more power (kW) than conventional, uncabled mooring systems. Every node on the system will have substantial expansion capability to meet the future requirements of an increasingly diverse research community and next generation sensing systems during its 30-year operating life.

As noted in Table 1-1, the Variant and VariantUpScope designs both remove and add components to the OOI infrastructure defined in the FND Baseline. The scientific and technical losses in the Variant involve the elimination of undersea cable, primary nodes and additional cabled infrastructure and instrumentation at the Blanco Fracture Zone site and the Subduction Zone site (Figures 2-9 and 2-10). In addition, the Mid-Plate site would have no scientific instrumentation. These infrastructure losses in the Variant impact the scientific capability of the OOI by

• reducing the regional reach of the high power and bandwidth provided by submarine cable;

• reducing the capability to address scientific questions within at least three of the six thematic areas of the OOI (Plate Scale Geodynamics, Fluid-Rock Interactions and the Subseafloor Biosphere, and Turbulent Mixing and Biophysical Interactions);

• reducing the expansion capability of the OOI over the extended lifetime of the infrastructure.

In the VariantUpScope, there would be cable between Mid-Plate and the Subduction Zone, and a primary node without instruments would be placed at the Subduction Zone site. This primary node would support an extension cable to the moorings on the Endurance Washington line, as is designed from the Hydrate Ridge node to the moorings on the Endurance Oregon line in the FND Baseline. The VariantUpScope design also represents a scientific and technical loss relative to the FND Baseline in the capability to address questions within the thematic areas, but the VariantUpScope does restore more power, bandwidth, and expansion capability than the Variant.

1.4.2 Gains Global: The Variant and VariantUpScope designs significantly increase the observing capabilities of the OOI on the Global scale. The proposed addition of the Argentine Basin Global Array would assure that the northern and southern high-latitude basins of both the Atlantic and the Pacific Ocean will be occupied with highly capable infrastructure that enables novel and interactive science in physical, chemical, geological, and biological oceanography. High latitude sites are thought to capture signals of climate variation before mid-latitude and equatorial regions, yet the high latitudes are remote, severely under-sampled, and have had little long-term data collected. The addition of the Argentine Basin will sample a biological regime in which airborne micronutrients are thought to be important and in which there is pronounced, persistent mesoscale structure, supporting investigation of the role of the ocean mesoscale. This site will enhance the OOI’s ability to address questions within the thematic areas of Ocean-Atmosphere Exchange and Climate Variability, Ocean Circulation, and Ecosystems; both themes encompassing carbon cycling and biogeochemical processes.


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Coastal: The Variant and VariantUpScope designs increase the observing capabilities of the OOI on the Coastal scale, although to different degrees. In the Variant design, the Endurance Array is enhanced with the addition of a cross-shelf mooring line on the Washington coast (47oN) at the 25 m, 80 m and 500 m isobaths. These isobaths match those of the moorings already in the Endurance Array off the Oregon coast at 44.6 oN. The 25 m mooring on the Endurance Washington line would be an exact copy of the sensor distribution and capabilities of the 25 m mooring on the Oregon line. In contrast, the 80 m and 500 m moorings on the Endurance Washington line under the Variant would be powered by the surface power packs used in the Pioneer Array, with fuel cell technology to provide sufficient power for the winched profilers (see details in Section 2). In the VariantUpScope, the 80m and 500m moorings on the Endurance Washington line would be powered by a connection to an extension cable from the Subduction Zone node, just as the Endurance Oregon 80m and 500m moorings are powered by a cable extension from the Hydrate Ridge node. As will be discussed in greater detail in Section 3, there are significant scientific gains in having two shelf-slope mooring lines within the Endurance Array. Previous network designs (Conceptual and Preliminary) of the OOI included the moorings off the Washington coast, but they were removed due to cost constraints following the Preliminary Design Review.

Many of the basic science goals of the PNW Endurance Array will be enhanced by having measurements at more than one along-shelf location. These measurements include changes in ecosystem response due to changes in atmospheric forcing (altered seasonal winds, changes in total wind forcing, different amount of precipitation or evaporation) or altered river input. Changes in these forcings, as modulated by climate variability, will result in changes to coastal ocean stratification and hence to the coastal ecosystem. The power and bandwidth capability provided by cabling the Endurance Washington line under the VariantUpScope increases the temporal resolution of water column structure with the winched profilers and makes it possible to add power-hungry sensors for benthic experimentation.

A more extensive discussion of science losses and gains will be presented in Section 3 of this addendum.


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2 OOI Network Variant Design

The OOI Variant design remains a system of systems, simplified into three scale groupings of marine infrastructure: coastal, regional and global. The addition of the Global site in the Argentine Basin expands the worldwide coverage of the marine infrastructure and the addition of the Washington Line (or Grays Harbor Line) expands the coverage of the Coastal Endurance Array. The removal of two sites (including nodes, cable, and sensors) from the RSN reduces the Regional Scale scientific footprint, as shown in Figure 2-1. For comparison, the reader is referred to the map of the FDR Baseline marine infrastructure in the OOI Final Network Design (Figure 4.3-1).

Figure 2-1. Location map of the OOI Variant marine infrastructure.


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The proposed modification (i.e., Variant) to the Final Network Design (FND) Baseline presented in this document reflects the same basic technical design solution presented at FDR with modified engineering detail for the components selected by the science/engineering team. These modifications to the FND Baseline are described in its component parts, i.e., changes to the Cyberinfrastructure, Global and Coastal Scale Nodes, and Regional Scale Nodes.

2.1 Variant Requirements

2.1.1 Level 2 Requirements The top-level of the acquirer requirements are recorded in the OOI Requirements Database (the Dynamic Object Oriented Requirements System [DOORS] application) as the following set of Level 2 Requirements modules:

• L2 Science Questions • L2 Science Requirements • L2 Cyber-User Requirements • L2 Educational Requirements • L2 Operational Requirements • L2 General Requirements

The Level 2 modules are grouped to facilitate traceability of requirements from the top level to any lower level of the requirements hierarchy. The modifications to the OOI infrastructure have been made under the existing L2 requirements.

2.1.2 Level 3 (L3) System Technical Requirements While the Level 2 Requirements capture the primary overarching requirements of the OOI, the System Technical Requirements contain some of the more detailed specifications and constraints. Because of the wide breadth of systems, software, hardware, operations, and services required for the OOI, the OOI System Technical Requirements are defined by and within each IO’s System Requirements and maintained jointly within the OOI DOORS system. As part of the NSF directed modification to the OOI FDR Baseline implementation, the L3 System Technical Requirements will be reviewed and updated, following the procedures outlined in the OOI System Engineering Management Plan (DCN 1100-00000).

2.2 Cyberinfrastructure – Variant Description

The Variant modifications to the Global, Regional, and Coastal elements of FND baseline will have little impact to cyberinfrastructure (CI). The suite of OOI core sensor types has not changed from FDR so no additional instrument agents are required. The schedule to install the Variant infrastructure will impact the CI schedule for development of the instrument agents. Four instrument agents have been identified that will be required six months ahead of the schedule presented at FDR. The Argentine Basin Array will be deployed during summer in the southern hemisphere six months ahead of the Irminger Sea Array, which had been scheduled to be the first global array installed.


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2.3 Coastal and Global Scale Nodes – Variant Description

2.3.1 Introduction The modification to the CGSN FND Baseline includes two principal components, the reinstatement of one Global Array and the Coastal Endurance Array Washington Line. The Global Scale Nodes now consist of four Global Arrays; Ocean Weather Station Papa in the Gulf of Alaska (50°N, 145°W), Irminger Sea offshore of southern Greenland (60°N, 39°W), Southern Pacific Ocean west of southern Chile (55°S, 90°W), and the Argentine Basin (42°S, 42°W). The Coastal Scale Nodes consists of two Coastal Arrays, on the eastern and western continental shelves of the U.S. The Pioneer Array, in the Mid-Atlantic Bight, samples a prototypical buoyancy-driven system on a broad continental shelf. The Endurance Array, a moored line off Newport, Oregon (44°N, 126°W to coast) and connected to the Regional Scale Nodes (RSN) cabled network, samples a prototypical upwelling regime on a narrow continental shelf. The Endurance array will be more fully implemented to include the originally planned moored line off Gray’s Harbor, Washington (47°N, 125°W to coast). The Argentine Basin site and Endurance Washington Line had been part of the design presented at CDR but were eliminated prior to PDR in an effort to focus on fewer, more capable sites at the direction of the Interim Observatory Steering Committee (iOSC, September 2007).

The additional infrastructure of the Variant design includes common elements that are reflected in the CGSN subsystems and team organization. During the development of the Final Network Design, a concerted effort was made to develop common infrastructure where the approach yields savings in construction costs, or operations and maintenance costs. The infrastructure added to the CGSN FDR Baseline was accommodated utilizing the common elements found at the existing coastal and global arrays, including buoy and mooring components, power generation, telemetry, and platform control. Added instruments and sensors were limited to the OOI core sensor types presented in the FDR Baseline.

Matching the geographic depiction of the CGSN (Figure 2-1) is a high-level functional block diagram (Figure 2-2) showing the relationships among CGSN elements as well as the relationship of CGSN elements to RSN (red) and Cyberinfrastructure (CI) (green).


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Figure 2-2. High-level functional block diagram of the CGSN

2.3.2 Global Scale Nodes The Global Scale Nodes (GSN) consists of four Global arrays based on a common design that combines surface moorings, subsurface moorings and gliders to achieve a unique space-time sampling capability for air-sea interaction and bio-physical processes on the ocean mesoscale (Fig. 2-3).


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Figure 2-3. Schematic of the Global Array design. Includes (foreground) a paired surface mooring and profiler mooring, (background) two taut subsurface, flanking moorings, and (dashed lines) three gliders. The moorings define a triangular region 50 km on a side (inset); gliders patrol along the axis of the triangle.

2.3.2.1 Global Argentine Basin Array Description

The Argentine Basin Global Array is similar to the configuration of the Irminger Sea array (OOI FND) and is described in detail below.

Argentine Basin

Location: 42°S, 42°W; Water Depth: 5200 meters

Mooring Types: Acoustically Linked Surface Mooring with Subsurface Profiler Mooring and Mesoscale Flanking Mooring Pair

Description of Infrastructure:

• One acoustically-linked Global Surface Mooring, with standard power (wind and solar) buoy and Iridium satellite telemetry

• One Global Hybrid Profiler mooring with one wire-crawler profiler and one winched profiler

• Two subsurface Mesoscale Flanking Moorings with fixed sensors and acoustic communications to gliders

• Acoustic telemetry link with transducer 10m below the surface buoy

• Inductive telemetry link within upper 1000 m of the Surface Mooring


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• Three gliders with extended endurance and acoustic communications to the Mesoscale Flanking Moorings

2.3.2.2 Global Core Sensors

The FND describes how the proposed global surface and subsurface moorings will support the suite of core sensors as well as the addition of science user sensors in the future. Varieties of options are described for adding sensors and instrument packages to global infrastructure. The increased focus on carbon cycling, climate change, and ocean acidification added pH, pCO2, and fluorescence sensors to the infrastructure, listed in Table 2-1 (additional sensors are shaded).

Table 2-1. Global Arrays core sensor and platform summary

Measurement Example Sensor Platform Comments

surface fluxes (bulk)

ASIMET EM buoys: Southern Ocean and Irminger

Redundant systems will ensure complete data sets from remote locations

surface fluxes (direct covariance)

HP-DCFS EM buoys Direct measurement of momentum flux and sensible and latent heat fluxes

CO2 flux PMEL EM buoys Simultaneous measurement of air-side and water-side pCO2

CO2 water Sunburst SAMI-CO2-1500

Winched profiler on Hybrid profiler moorings

200 m depth to surface

surface wave spectra TriAxys EM buoys Motion sensors in buoy hull temperature and conductivity

Seabird 37 EM moorings 5 m below surface at EM termination

Seabird 37 EM moorings, Flanking Moorings

12 locations on mooring line between 30 m and 1500 m depth, inductive telemetry

Seabird 52MP



Seabird 52MP

Moored profiler on Hybrid profiler moorings

230 m depth to near bottom

Seabird 41CP

Gliders Saw-tooth transects to 1000 m

high-precision pressure Seabird 52MP



Seabird 52MP



Seabird 41CP


mean currents Nortek Aquadopp

EM moorings 5 m below surface at EM termination

RDI ADCP EM moorings Near surface to 600 m (downlooking) RDI ADCP Flanking moorings 600 m to near surface (uplooking) turbulent velocities Nobska

MAVS Winched profiler on Hybrid profiler moorings



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Nobska MAVS



dissolved oxygen Aanderaa optode

Flanking moorings 30 m depth at top of flotation sphere

Aanderaa optode



Aanderaa optode



Aanderaa optode


pH Sunburst SAMI-pH


Sunburst SAMI-pH

Surface moorings 20 m depth and 100 m depth below surface

optical attenuation and absorption

Wetlabs AC-9 Winched profiler on Hybrid profiler moorings


Chl-a fluorescence, optical backscatter

Wetlabs Eco-BB2F


Wetlabs Eco-BB2F

Surface mooring 15 m depth below surface

Wetlabs Eco-BB2F



Wetlabs Eco-BB2F



Wetlabs Eco-BB2F

Gliders saw-tooth transects to 1000 m

spectral irradiance Satlantic OCR-507



nitrate Satlantic ISUS



zooplankton/fish sonar Dual Simrad ES-60

Surface mooring 15 m depth below surface

2.3.2.3 Installation and Servicing

Planning for and occupation of the Argentine Basin Array will be coordinated with international research programs such as Climate Variability and Predictability (CLIVAR), the international ocean time series scientific steering group (OceanSITES), and colleagues in Argentina, including at the University of Buenos Aires and the Hydrographic Service of the Argentine Navy. Shiptime requests will be made through UNOLS (University-National Oceanographic Laboratory System). In addition, the timing of the mooring servicing will be made know to international ship operators through POGO (Partnership for the Observation of the Global Ocean) and other ship resource sharing groups.


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2.3.3 Coastal Scale Nodes

2.3.3.1 Pioneer Array Description

The Pioneer Array remains as described in the FND Baseline, a moored array that is aligned perpendicular to isobaths and spans the shelf break supplemented by nine mobile platforms – six gliders and three AUVs.

2.3.3.2 Pioneer Array Core Sensors

The FND Baseline describes how the Pioneer Array will support the suite of core sensors as well as the addition of science user sensors in the future. The increased focus on carbon cycling, climate change, and ocean acidification added pH, pCO2, and fluorescence sensors to the infrastructure, listed in Table 2-2 (additional sensors are shaded).

Table 2-2. Pioneer Array core sensor and platform summary



ASIMET EOM buoys Nearby NDBC buoys will supplement Pioneer Array meteorology


LP-DCFS EOM buoys Direct measurement of momentum and buoyancy fluxes

CO2 flux PMEL Central EOM buoy Simultaneous measurement of air-side and water-side pCO2

CO2 water Sunburst SAMI-CO2-1500

Winched profiler 2 m above bottom to surface

Sunburst SAMI-CO2-1500

EOM moorings 2 m above bottom on MFN

surface wave spectra TriAxys Central EOM buoy Motion sensors in buoy hull temperature and conductivity

Seabird 16 EOM moorings 7 m below surface at EOM termination, 2 m above bottom on MFN

Seabird 52MP

Winched profilers 2 m above bottom to surface

Seabird 52MP

Moored profilers Near bottom to 15 m below surface

Seabird 41CP


Seabird 49 AUVs Saw-tooth transects to 500 m high-precision pressure Seabird 53 EOM moorings 2 m above bottom on MFN Seabird

52MP Winched profilers 2 m above bottom to surface

Seabird 52MP


Seabird 41CP


Seabird 49 AUVs Saw-tooth transects to 500 m mean currents Nortek

Aquadopp EOM moorings 7 m below surface at EOM

termination, 2 m above bottom on MFN

RDI ADCP Winched profiler base Near bottom to near surface RDI ADCP Moored profiler base Near bottom to near surface


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Nortek Aquapro


RDI ADCP AUVs Saw-tooth transects to 500 m turbulent velocities Nobska

MAVS Winched profilers 2 m above bottom to surface

Nobska MAVS



EOM moorings 7 m below surface at EOM termination, 2 m above bottom on MFN

Seabird 43 Winched profilers 2 m above bottom to surface Seabird 43 Moored profilers Near bottom to 15 m below surface Aanderaa

optode Gliders Saw-tooth transects to 1000 m

Aanderaa optode

AUVs Saw-tooth transects to 500 m

pH Sunburst SAMI-pH

EOM moorings 5 m below surface at EOM termination

Sunburst SAMI-pH

Inshore EOM mooring 2 m above bottom on MFN


Wetlabs AC-9 EOM moorings 5 m below surface at EOM termination, 2m above bottom on MFN

Wetlabs AC-9 Winched profilers 2 m above bottom to surface Chl-a and CDOM fluorescence, optical backscatter

Wetlabs Eco-Puck


Wetlabs Eco-Puck

Surface moorings 7 m depth below surface

Wetlabs Eco-Puck


Wetlabs Eco-Puck


Wetlabs Eco-Puck

AUVs Saw-tooth transects to 500 m

photosynthetically active radiation (PAR)

Biospherical QSP-2100






Satlantic OCR-507




Satlantic ISUS


nutrients (NO2,NO3,PO4,SiO4)

SubChem AUVs Saw-tooth transects to 500 m

phytoplankton-zooplankton sonar

Simrad EK-60

EOM moorings Vertical profiler, uplooking from MFN


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2.3.3.3 Endurance Array Oregon Line Description

The Endurance Array off the coast of Oregon (Endurance Oregon Line), also referred to as the Newport Line, was presented as the Endurance Array in the FDR Baseline. As presented at FDR, the Endurance OREGON Line remains as described in the OOI Final Network Design (OOI document control number 1101-00000), summarized below.

Location: Moored array line: 44° 39’N, 126°W to coast; Water Depth: 500-25 meters.

Glider sampling area: 44° 30’ to 48° 00’N, 126°W to coast.

Platform Types: Three fixed platform sites at 25, 80, and 500 m water depth (two cabled and one un-cabled) supporting surface moorings, water column profilers and benthic boundary layer sensors, supplemented by six gliders.

Description of Infrastructure:

• Two surface moorings with wind and photovoltaic power generation, iridium communications, and meteorological sensors (80, 500 m)

• One EM surface mooring with battery power and iridium communications (25 m) • Two bottom-mounted winched profiler moorings one stand-alone (25m) and one cabled to RSN

(80 m) • One hybrid profiler mooring with subsurface profiler and winched profiler cabled to RSN (500 m) • One uncabled benthic multifunction node (MFN) with sensors, electrical communications to the

surface, and supplementary battery power provided by the surface buoy (25 m) • Two cabled benthic experiment packages (BEP) with fiber optic communications and power

provided through primary nodes attached to the RSN (80 m, 500 m) • Six gliders

2.3.3.4 Endurance Array Oregon Line Core Sensors

The FND Baseline describes how the Endurance Oregon Line will support the suite of core sensors as well as the addition of science user sensors in the future. The increased focus on carbon cycling, climate change, and ocean acidification is accommodated by a reconfiguration of pH sensors and additional pCO2

sensors on the infrastructure, as listed in Table 2-3 (additional sensors are shaded).

Table 2-3. Endurance Oregon Line core sensor and platform summary



ASIMET EM buoys Redundant systems will ensure complete data sets from remote locations


HP-DCFS EM buoys Direct measurement of momentum flux and sensible and latent heat fluxes

CO2 flux PMEL EM buoys Simultaneous measurement of air-side and water-side pCO2

CO2 water Sunburst SAMI-CO2 1500


Sunburst SAMI-CO2 1500



Benthic Nodes 2 m above bottom on BEP

surface wave spectra TriAxys EM buoys Motion sensors in buoy hull


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temperature and conductivity

Seabird 16 EM moorings 5 m below surface at EM termination

Seabird 52MP


Seabird 52MP

Winched profiler on hybrid profiler mooring


Seabird 52MP

Moored profiler on Hybrid profiler mooring


Seabird 16 Benthic Nodes 2 m above bottom on BEP Seabird

41CP Gliders Saw-tooth transects to 1000 m

high-precision pressure Seabird 52MP


Seabird 52MP



Seabird 52MP



Seabird 16 Benthic Nodes 2 m above bottom on BEP Seabird

41CP Gliders Saw-tooth transects to 1000 m

mean currents Nortek Aquadopp


Nortek Aquadopp


Nortek Aquadopp



RDI ADCP EM moorings Near surface to 300 m (downlooking) RDI ADCP Benthic Nodes 300 m range, uplooking from BEP Nortek

Aquapro Gliders Saw-tooth transects to 1000 m

turbulent velocities Nobska MAVS

EM buoys Below buoy hull

Nobska MAVS



Nobska MAVS




Seabird 43 Winched profilers 2 m above bottom to surface Seabird 43 Winched profiler on

hybrid profiler mooring


Seabird 43 Moored profiler on Hybrid profiler mooring


Aanderaa optode



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Aanderaa optode


pH Sunburst SAMI-pH


Sunburst SAMI-pH

Subsurface platform on hybrid profiler mooring

200 m depth below surface

Sunburst SAMI-pH

Benthic Nodes 2 m above bottom on BEP, all sites


Wetlabs AC-9 EM moorings 5 m below surface at EM termination

Wetlabs AC-9 Winched profilers 2 m above bottom to surface

Wetlabs AC-9 Winched profiler on hybrid profiler mooring


Wetlabs AC-9 Benthic Nodes 2 m above bottom on BEP Chl-a and CDOM fluorescence, optical backscatter

Wetlabs Eco-Puck


Wetlabs Eco-Puck


Wetlabs Eco-Puck



Wetlabs Eco-Puck



Wetlabs Eco-Puck












Satlantic OCR-507


Satlantic OCR-507





Satlantic ISUS


Satlantic ISUS




Simrad EK-60

Benthic Nodes Vertical profile, uplooking from BEP


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digital still camera Prosilica GE2040


hydrophone, passive Naxys Benthic Nodes, Offshore and Shelf sites

2 m above bottom on BEP

2.3.3.5 Endurance Array Washington Line Description

The Endurance Array Washington Line (Endurance Washington Line), also referred to as the Grays Harbor Line, is reinstated as part of the Endurance Array in the Variant design. The Endurance Washington Line adds fixed assets to observe cross-shelf variability in a coastal region off Washington, which is subject to upwelling and buoyancy forcing from the Columbia River and the Strait of Juan de Fuca. The Endurance Array Washington Line extends the fixed time series footprint and expands the experimental scope provided by the Endurance Array Oregon Line and the RSN cabled infrastructure (Figure 2-4).

The following descriptions are for the Endurance Array Washington Line.

Location: Moored array line: 47° N, 125°W to coast; Water Depth: 500-25 meters.

Platform Types: Three fixed un-cabled platform sites at 25, 80, and 500 m water depth supporting surface moorings, water column profilers and benthic boundary layer sensors.

Description of Infrastructure added by Endurance Array Washington Line:

• Two EOM surface moorings with wind, photovoltaic and fuel cell power generation, high speed and low speed satellite communications, and meteorological sensors (80, 500 m)

• One EM surface mooring with battery power and Iridium satellite communications (25 m) • Two bottom-mounted stand-alone winched profiler moorings at 25m and 80 m water depth with

acoustic communications to the surface buoy • One wire crawler profiler mooring at 500 m • One un-cabled benthic multifunction node (MFN) with sensors, electrical communications to the

surface, and supplementary battery power provided by the surface buoy (25 m) • Two un-cabled benthic multifunction nodes (MFN’s) with fiber optic communications to the

surface and power provided through surface moorings (80 m, 500 m)

The configuration of Endurance Array Washington Line elements is shown schematically in Figure 2-4.


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Figure 2-4. Plan view map of the Endurance Array, including the Washington Line and Oregon Line

The Endurance Washington Line (un-cabled) mooring sites are at 25 m, 80 m and 500 m, offshore of Grays Harbor, Washington. The Endurance Oregon Line moored sites at 25 m, 80 m and 500 m and the connection to the RSN cabled infrastructure, at 80 m and 500 m sites, is also shown, as is the coverage provided by six gliders.

Geographic locations for the Endurance Array Oregon Line platforms are given in Table 4.3-7 of the OOI FND document. Geographic locations for the Endurance Array Washington Line platforms are given in Table 2-4 below.


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Table 2-4. Platform locations and depths for the Endurance Array Washington Line.

Location description

Latitude °N

Longitude °W

Depth m Comments

Offshore 46.91 124.95 500 Offshore site, un-cabled

Shelf 47.00 124.27 80 Mid-shelf site un-cabled

Inshore 47.00 124.162 25 Inshore site, un-cabled

2.3.3.6 Endurance Array Washington Line Core Sensors and Platforms

The core science sensors for the Endurance Washington Line are listed in Table 2-5. As with Global, Pioneer, and other Endurance Oregon Line sensors, these sensors are in the OOI Core Sensor List developed to satisfy the OOI science requirements. Meteorological sensors and near-surface ocean sensors are deployed at the slope and mid-shelf sites. Meteorological sensors are deployed to resolve first order cross-shelf gradients in surface heat and momentum fluxes (including wind stress curl and cross-shelf diurnal wind variability). Upper ocean sensors will be deployed at these buoys and at the inner-shelf site to resolve cross-shelf gradients in water properties including nutrients and ocean color. The in situ measurements provided by these buoys will be an important source of ongoing improvement of algorithms for satellite estimation of wind stress and ocean color near the sea-land boundary. The moored profilers and bottom-mounted ADCP’s are the primary tools for time-series monitoring of the water column, providing interdisciplinary observations resolving the semi-diurnal tidal band and below. Sampling with the six Endurance Coastal Gliders will overlap directly with the higher frequency fixed node observations above in Table 2-4.

Table 2-5. Endurance Array Washington Line core sensor and platform summary.



ASIMET EOM buoys Redundant systems will ensure complete data sets from remote locations


HP-DCFS EOM buoys Direct measurement of momentum flux and sensible and latent heat fluxes

CO2 flux PMEL EOM/EM buoys Simultaneous measurement of air-side and water-side pCO2 and kinetic gas transfer velocity

CO2 water Sunburst SAMI-CO2 1500






surface wave spectra TriAxys EOM/EM buoys Motion sensors in buoy hull temperature and conductivity

Seabird 16 EOM/EM moorings 7 m below surface at EM termination


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Seabird 52MP


Seabird 52MP

Wire crawler profiler on offshore profiler mooring

near bottom to 15 m below surface

Seabird 16 Multifunction Nodes 2 m above bottom on MFN high-precision pressure Seabird

52MP Winched profilers 2 m above bottom to surface

Seabird 52MP



Seabird 16 Multifunction Nodes 2 m above bottom on MFN mean currents Nortek

Aquadopp EOM/EM moorings 7/5 m below surface at EOM/EM

termination Nortek

Aquadopp Winched profilers 2 m above bottom to surface

RDI ADCP EM moorings Near surface to 300 m (downlooking) RDI ADCP Multifunction Nodes 300 m range, uplooking from MFN turbulent velocities Nobska

MAVS EOM/EM buoys Below buoy hull

Nobska MAVS



Nobska MAVS

Multifunction Nodes 2 m above bottom on MFN


EOM/EM moorings 7/5 m below surface at EOM/EM termination

Seabird 43 Winched profilers 2 m above bottom to surface Seabird 43 Wire crawler profiler

on offshore profiler mooring


Aanderaa optode


pH Sunburst SAMI-pH

EOM/EM moorings 5 m below surface at EOM/EM termination

Sunburst SAMI-pH

Profiler mooring 15 m below surface on sub-surface float

Sunburst SAMI-pH

Multifunction Nodes 2 m above bottom on MFN (25m and 80m)


Wetlabs AC-9 EM moorings m below surface at EM termination

Wetlabs AC-9 Winched profilers 2 m above bottom to surface Wetlabs AC-9 Multifunction Nodes 2 m above bottom on MFN Chl-a and CDOM fluorescence, optical backscatter

Wetlabs Eco-Puck


Wetlabs Eco-Puck


Wetlabs Eco-Puck




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Satlantic OCR-507




Satlantic ISUS



Simrad EK-60

Multifunction Nodes Vertical profile, uplooking from MFN

digital still camera Prosilica GE2040


2.3.3.7 Endurance Array Washington Line Technical Approach

The backbone of the Endurance Washington Line will be three fixed sites aligned nearly perpendicular to isobaths and spanning from offshore (500 m), mid-shelf (80 m) and inshore (25 m) regimes offshore of Washington (Figure 2-5). The offshore and shelf sites combine fully-instrumented surface platforms electrically, optically and mechanically linked to benthic boundary layer sensors and a stand-alone profiler. The inshore site combines a wave-hardened surface platform electromechanically linked to benthic boundary layer sensors and a stand-alone winched profiler. The three environments are linked physically, biologically, and geologically, yet represent distinctly different processes. As an example, wave and buoyancy forcing is especially important at the 25 m site, while local and remote wind forcing and buoyancy forcing are dominant at the mid-shelf site and slope currents and offshore mesoscale variability is important at the slope site.


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Figure 2-5 . Schematic diagram of the Endurance Array Washington Line. Shown are surface-mooring/profiler pairs at offshore, shelf and inshore sites, benthic multifunction nodes (MFN), Gliders will patrol the region, with one offshore line coincident with the moored array.

Surface moorings will also be present at the 500 m and 80 m sites. These moorings will provide continuous meteorological and near-surface oceanographic measurements.

At the interface between the shelf and the near shore zone, the Endurance Array Washington Line 25 m site is both scientifically important and logistically challenging. Breaking waves and sediment transport driven by winter storms make relatively delicate surface buoy towers and meteorological sensors impractical. Instead we will install a surface buoy hardened to overtopping by waves. The buoy will support near-surface oceanographic measurements and two-way communications with the seafloor, and will also provide power to benthic boundary layer sensors via a battery pack. A stand-alone winched profiler will also be deployed at this site, communicating through acoustic modem and Iridium.

The three fixed sites are correlated in the cross-shelf direction, but are each associated with unique physical, geological, and biological processes. To bridge the distances between the fixed sites and allow adaptive sampling, we will use six autonomous gliders. These gliders will support sensors similar to those on the winched profilers. Together, the gliders, surface buoys, profilers, and benthic nodes will provide near real time data from the air-sea interface, through the water column and to the sea-sediment interface. This full water column coverage at multiple sites provides experimental capabilities that are unique within the OOI.


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2.3.3.7.1 Endurance Array Washington Line Surface Moorings The Endurance Washington Line moorings use the same designs as Pioneer moorings (OOI Final Network Design section 4.3.3.3.1) at the 500 m and 80 m sites and the inshore Endurance mooring (OOI Final Network Design section 4.3.3.7.1) at the 25 m site. For convenience, descriptions of these moorings are paraphrased here.

The Endurance Array Washington Line offshore and shelf surface moorings (Figure 2-6) will provide meteorological observations, power to surface and subsurface instruments, and real time data transmission. These moorings will be similar in design to those used in the Pioneer Array. Because they will support extensive water column and benthic sensors they will carry optical fiber or power transmission from the surface to the multifunction node at the bottom. Like the Pioneer Array buoys, power will be generated using a combination of wind turbines, photovoltaic panels and methanol fuel cells. Wind, solar, and fuel cell power will be used to charge storage batteries in the buoy, and ultimately will be delivered to instrumentation over the entire mooring, including the MFN. The buoy control and communication system will be the same as the Pioneer surface moorings, including acoustic communication with subsurface sensors. One DCL will be located internal to the surface buoys and one DCL will be located on the instrument frame at 5 m beneath the buoy. The surface mooring will support sensors at the air-sea interface, and on the instrument frame at the 5 m termination, as described in the Endurance Washington Line core sensor summary (Table 2-5).

Figure 2-6. Endurance Array Washington Line 500 m and 80 m Surface Mooring.


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The inshore 25-m surface mooring (Figure 2-7) will comprise a surface buoy, an EM mooring strength member running to the bottom, and a MFN with power, sensors, and data distribution capabilities. The MFN also provides the weight necessary to anchor the system. The surface buoy has a welded aluminum core structure and closed-cell polyethylene foam buoyancy module about 1.5 m in diameter. It has a welded aluminum tower structure approximately 2 m high to support antennas, a radar reflector, and amber flashing light. It is hardened for submergence by breaking waves. The buoy contains an electronics controller consisting of a microcomputer to control power supplied to sensors, acquire and log data, and transmit recorded data to shore via satellite and/or radio links. Power is stored in batteries housed in a chamber within the buoy hull structure. Telemetry to and from the mooring is via satellite and/or radio links including Iridium, Freewave, and WiFi.

Figure 2-7. Endurance Array Washington Line 25m Surface Mooring.


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The 25 m surface mooring will support sensors at the air-sea interface, and on the instrument frame at the EM termination, as described in the Endurance Washington Line core sensor summary (Table 2-5). Control and data signals to and from sensors below the buoy flow along copper conductors built into the mooring strength member elements. These include steel armored EM cable approximately 15 mm in diameter, EM urethane molded chains approximately 75 mm in diameter and 5 m in length, and, depending on water depth, one or two EM mooring stretch hoses that are approximately 100 mm in diameter and can stretch from an original length of 15 m to upwards of 32 m, and serve to reduce shock loading in the mooring for increased longevity. Frames for sensors are provided for the mounting of instruments at the junctions between the various mooring elements. Electrical breakouts provide the instruments with connections for power and telemetry. The EM cable allows for high-speed communication and power transmission between the surface buoy controller and the MFN instrumentation.

2.3.3.7.2 Endurance Array Washington Line Winched Profilers The Endurance Array Washington Line 80 m and 25 m moorings use the same designs as the inshore Endurance Oregon mooring (OOI Final Network Design section 4.3.3.7.2) at the 25 m site. For convenience, the description of the winched profiler in stand alone mode is paraphrased here.

Each Endurance Washington Line mooring site will have profilers paired with the surface moorings (Figure 2-5). The inshore and shelf profilers will be stand-alone winched profilers. The stand-alone winched profiler is internally powered and will communicate via Iridium telemetry while at the sea surface. The profiler can also communicate acoustically with the surface mooring located less than 2 km away. Winched profilers consist of an aluminum bottom frame that is approximately 1.7 m diameter and 1.4 m high, with mounting points for an ADCP and other near bottom sensors, anchor weight, an anchor release mechanism, and a profiling package that includes flotation material, a winch system, a sealed lead acid battery pack (12 Ah at 18-42 volts), controller, scientific sensors, and a radio and Iridium satellite telemetry system. The profiler package will extend 2 m or less above the top of the base. The connection between the bottom frame and profiling package is a synthetic line approximately 8 mm in diameter. When the profiling package is at the bottom of its travel it seats in the bottom frame and can communicate with and download data via an inductive link. These profiler systems can operate in depths approaching 200 meters depending on current conditions. The bottom frame will be used as a stand-alone battery-powered base. The standalone base will contain a set of lithium ion battery packs (72 Ah at 25-42 volts) providing a power reservoir for the winched profiler. It will have the capability to communicate data to a nearby surface buoy via an acoustic modem.

2.3.3.7.3 Endurance Array Washington Line Offshore Profiler The 500 m offshore profiler mooring infrastructure will use the same design as the Pioneer profiler mooring described in the OOI Final Network Design section 4.3.3.3. For convenience, the description of the Pioneer profiler mooring is repeated here with appropriate name substitutions.

The Endurance Washington Line Profiler Mooring (Figure 2-8) will support sensors in the profiling body and will have a frame mounted, upward looking ADCP, as described in the Endurance Washington Line core sensor summary (Table 2-5). The Endurance Washington Line Profiler Mooring will be of conventional design from the anchor to the subsurface flotation sphere, but will also include a surface expression. An electromechanical (EM) stretch mooring hose will connect a small surface buoy to the subsurface flotation sphere, providing compliance in the upper 15-20 m of the mooring (to accommodate tidal excursions and wave motion) while allowing the flotation sphere to maintain vertical tension in the wire-rope portion of the mooring on which the profiler rides. Profiler moorings will be equipped with a wire-crawler type profiler that will translate all but the upper 15 m of the water column and an ADCP situated near the bottom. Both will transmit data using inductive modems over the jacketed steel cable with seawater return, through conductors in the flotation sphere and stretch hose, to a receiver in the surface buoy.


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Figure 2-8. Endurance Array Washington Line Offshore Profiling Mooring.

The profiler mooring surface buoy will be a small (~1 m diameter) steel sphere containing a simple platform controller, Iridium modem, and antenna. The design will be based on an existing, power-efficient controller used for long-term Arctic deployments with similar instrumentation (www.whoi.edu/itp). An alkaline battery pack on the buoy will power both satellite and inductive communications for a year while permitting command and control from shore as part of any data transmissions via the Iridium link. The candidate profiler is available from the factory with an integrated inductive modem and controller, while the ADCP will be purchased with an inductive modem, controller, and internal battery packs. The profiler is capable of approximately one million meters of travel, allowing six profiles per day for a year in 500 m water and the ADCP will be capable of at least one profile per hour for a year.


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2.3.3.7.4 Endurance Array Washington Line Multifunction Nodes The inshore, shelf and offshore sites will have a multifunction node (MFN) attached to the base of the surface mooring. This MFN will carry sensors, and provide power and control similar to that of the low voltage node (LVN) described for the Endurance OREGON Line mooring array (OOI Final Network Design sections 4.3.3.7.4, 4.4.3.2), but without a cabled connection. Instead, the MFN will be powered internally and also receive power from the surface buoy. It will communicate with the surface buoy via an EOM communication link at the 500 m and 80 m sites and an EM link at the 25 m site. The MFN will provide power and real time communication with core sensors and future user experiments.

The MFN design is identical to that used for the Pioneer Array (OOI Final Network Design section 4.3.3.3.1). For convenience, the description of the Pioneer MFN is paraphrased here with appropriate modifications. The Endurance Washington Line MFN will be identical to the Pioneer array central site (P1) in that it will not include an AUV dock, but instead be dedicated to instruments including science-user added instruments. The MFN is a benthic platform to supply communications and power for “clients” that include unspecified science-user instrumentation. For the Endurance Washington Line, the MFN power system will initially support multiple, low power sensors with regular sample intervals. All three MFNs will be capable of supporting multiple onboard (e.g. frame-mounted) sensors as well as external sensor packages connected to the MFN frame by an ROV wet-mate connector. Power available for science-user instrumentation will be limited at the inshore site due to battery limitations in the inshore buoy, but the MFN at the shelf and offshore sites will have power from the surface mooring, allowing sensors and instrument packages to be placed at the mid-shelf and continental slope.

The MFN acts as a power and telemetry breakout between the mooring EOM (EM) cable and the science users. The MFN has equivalent functionality as the surface mooring including the fully redundant platform controller and two DCL. The MFN platform controller will supervise power usage requests based on the total power available from the surface. If the power drawn by users exceeds power available the platform controller will scale back users based on a predetermined schedule to avoid system damage or an ungraceful shutdown.

2.3.3.8 Endurance Array Washington Line Installation and Servicing Requirements

Since many of the non-cabled Endurance Washington Line components are the same as Pioneer Array components, testing will occur when the Pioneer components are tested. Winched profilers will be developed and tested with deployments of increasing duration off the Oregon coast in years two and three. The nearshore buoy will also be tested in years two and three. The initial operational deployment of the nearshore buoy would occur in spring with a recovery and thorough examination of the components in fall. Redeployment of the buoy over the more severe winter conditions would occur only after the mooring performance and wear on mooring components during the summer deployment was verified.

Our collective experience indicates that most instruments will require servicing twice per year in the coastal environment because of biofouling. Both surface moorings and stand-alone subsurface profilers can be serviced using an intermediate class UNOLS ship such as the R/V Wecoma. At each turnaround, sensors would be cleaned and checked as would mooring hardware. Most sensors will need recalibration once per year and the budget for this is in the initial operations and maintenance years. Based on experience, we anticipate that many mooring components (e.g., molded chain and compliant hose) will last at least two years and have budgeted accordingly.

2.3.4 Shore-Side Facilities The same shore side facilities that support other CGSN nodes (OOI Final Network Design section 4.3.4) will support the re-established Endurance Washington Line and Argentine Basin Global Array.

There will be three shore facilities to support the CGSN operations and maintenance plan. The facilities reside at Woods Hole, MA, San Diego, CA, and Corvallis, OR and are responsible for system operations, fields operations, and data operations. The Woods Hole shore station, operated by Woods Hole Oceanographic Institution, will manage the Pioneer Array and Irminger Sea Global Array assets including gliders and AUVs. The San Diego shore station operated by Scripps Institution of Oceanography, will manage the Station Papa, Argentine Basin, and Southern Ocean Global Arrays including gliders. The Corvallis shore station, operated by Oregon State University, will manage the Endurance Array including the Oregon and Washington Lines and gliders.


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2.4 Regional Scale Nodes – Variant Description

This section describes the NSF-directed proposed changes for the Regional Scale Nodes (RSN), now called Variant design, and an alternate design called VariantUpScope. For reference, the FND baseline is shown in Figure 2-9; Figure 2-10 shows the Variant design.

Figure 2-9. FDR Baseline that includes the Warrenton and Pacific City shore stations, connection to the Cyber-POP at Portland Oregon, the sub-sea cable segments, and the nine Primary Nodes.

Figure 2-10. The Variant (labeled Option 1) showing the loss of cabled infrastructure at the Blanco and Subduction Zone Sites, and loss of all science sensors at the Mid-Plate Site. Also lost are the Warrenton shore station and associated backhaul. The three moorings of the reinstated Endurance Array Washington Line off Grays Harbor are also shown.


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The FDR Baseline configuration includes two shore stations and nine Primary Nodes (Figures 2-9 and 2-11) with the following designations: Node 1A (Hydrate Ridge) and Node 1B (Southern Hydrate Ridge); Node 2A (Blanco); Node 3A (Axial Seamount) and Node 3B (Eastern Caldera); Node 4A (Subduction Zone), and Node 5A (Mid-Plate). The Hydrate Ridge infrastructure also includes two additional Primary Nodes, Node 1C and Node 1D, which comprise part of the Endurance Array Oregon Line extension: Node 1C is shared by RSN and CGSN. The shore station located in Pacific City, Oregon includes three cable landings serving Hydrate Ridge, Blanco Fracture Zone, Axial Seamount, and the Mid-Plate site. A second shore station will be in Warrenton, Oregon that will have one cable landing serving the Subduction Zone Site. The backhaul between the Warrenton and Pacific City shore stations, provides shore-based redundancy for the system. The Primary Nodes convert the high cable line power voltage (10 kV) to a lower (375 V) level and distribute it to Science Ports along with communications and timing signals. They also pass on 10 Gb/sec data transmission to the individual work sites. Each cabled moorings will receive 3500 W with continuous 1000 Mb/s data transmission. For detailed technical descriptions of the Primary and Secondary Infrastructure see the OOI Final Network Design document, sections 4.4.2 and 4.4.3.

The Variant design removes of all primary and secondary infrastructure at the Blanco Transform Fault Site and the Subduction Zone Site, and removes all science sensors at the Mid-Plate Site (See Table 2-6). The Hydrate Ridge and Axial Seamount Sites remain unchanged. With the loss of the Subduction Zone Site, the Warrenton shore station is also removed in the Variant, as is the backhaul between the Washington and Pacific City shore stations. The high-level block diagram for Variant is shown in Figure 2-11.

Table 2-6. RSN infrastructure and sensors remaining (black) and removed (in red) in the Variant.

Variant Cable Nodes Sensors Site 1 Hydrate Ridge No Changes

Same as FDR Baseline Same as FDR Baseline Same as FDR Baseline

Site 2 Blanco Transform Fault All Infrastructure Removed All Science Removed

Removal of 347 km backbone cable. 160 km extension cable

Removal of PN1A*, 1 MPJ-Box†, 2 LV Nodes††, 8 Seismometer multiplexers

Removal 9 broadband seismometers with accelerometers, 9 hydrophones, 1 current meter, 1 pressure sensor, 1 HPIES

Site 3 Axial Seamount No Changes

Same as FDR Baseline Same as FDR Baseline Same as FDR Baseline

Site 4 Subduction Zone All Infrastructure Removed All Science Removed

Removal of 210 km backbone cable, 41 km extension cables

Removal of 1 MP J-Box, 1 LV Node, 1 LP J-Box¥

Removal of 2 Broadband seismometer with accelerometers, 3 short-period seismometers, 2 hydrophones, 2 current meters, 2 pressure sensors, 1 HPIES

Site 5 Mid-Plate All Science Removed

Removal of 1.5 km extension cables Removal of 1 MP J-Box

Removal 1 broadband seismometer with accelerometer, 1 hydrophones, 1 current meter, 1 pressure sensor, 1 HPIES

*PN = Primary Node, †Medium Powered J-Box, ††LV = Low Voltage Nodes, ¥Low Power J-Box


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Figure 2-11. The high-level block diagram for the Variant (Option 1) showing the RSN Infrastructure and the Primary and Secondary Infrastructure associated with the CSN Endurance Extension Line. The RSN and CSN share Primary Node 1C. Components shown in red are those removed from the FDR Baseline design.


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3 VariantUpScope

3.1 Coastal Scale Nodes – VariantUpScope Description

3.1.1 Endurance Array Washington (WA) Line VariantUpScope Description The Endurance Array Washington Line (Endurance Washington Line), also referred to as the Grays Harbor Line, is reinstated as part of the Endurance Array in the VariantUpScope design. The VariantUpScope design differs from the Endurance Washington Line that was described in the Conceptual Network Design (CND) in several respects. Unlike the CND design, the Endurance Washington Line would mirror the FND Baseline design (and Variant design) in mooring locations (25, 80, and 500 m), including cabled connections at 80 and 500 m sites; providing a matching scientific footprint to the Endurance Oregon Line, including power and bandwidth capabilities. The Endurance Array Washington Line extends the fixed time series footprint and broadens the scientific capabilities (i.e., expandability) provided by the Endurance Array Oregon Line and the RSN cabled infrastructure.

The following descriptions are for the Endurance Array Washington Line - VariantUpScope.

Location: Moored array line: 47° N, 125°W to coast; Water Depth: 500-25 meters.

Platform Types: Three fixed platform sites at 25, 80, and 500 m water depth (two cabled and one un-cabled) supporting surface moorings, water column profilers and benthic boundary layer sensors.

Description of Infrastructure added by Endurance Array Washington Line:

• Two EM surface moorings with wind and photovoltaic power generation, iridium communications, and meteorological sensors (80 m, 500 m)

• One EM surface mooring with battery power and iridium communications (25 m)

• Two bottom-mounted winched profiler moorings one stand-alone (25 m) and one cabled to RSN (80 m)

• One hybrid profiler mooring with subsurface profiler and winched profiler cabled to RSN (500 m) via the Subduction Zone (N4A).

• One uncabled benthic multifunction node (MFN) with sensors, electrical communications to the surface, and supplementary battery power provided by the surface buoy (25 m)

• Two cabled benthic experiment packages (BEP) with fiber optic communications and power provided through primary nodes attached to the RSN (80 m, 500 m)

The configuration of Endurance Array Washington Line elements is shown schematically in Figure 3-1.


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Figure 3-1. Plan view map of the VariantUpScope Endurance Array, including the Washington Line and Oregon Line.

The Endurance Array Washington Line (un-cabled) mooring sites are at 25 m, 80 m and 500 m, offshore of Grays Harbor, Washington. The Endurance Oregon moored array sites at 25 m, 80 m and 500 m and the connection to the RSN cabled infrastructure, at 80 m and 500 m sites, is also shown, as is the coverage provided by six gliders.

Geographic locations for the Endurance Array Oregon Line platforms are given in Table 4.3-7 of the OOI FND document. Geographic locations for the Endurance Array Washington Line platforms are given in Table 3-1 below.


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Table 3-1. Platform locations and depths for the Endurance Array Washington Line.

Location

description Latitude

°N Longitude

°W Depth

m Comments

Offshore 46.91 124.95 500 Offshore site, cabled

Shelf 47.00 124.27 80 Mid-shelf site cabled

Inshore 47.00 124.162 25 Inshore site, un-cabled

3.1.2 Endurance Array Washington Line - VariantUpScope Core Sensors and Platforms The core science sensors for the Endurance Washington Line VariantUpScope are identical to the core sensors at the Variant Endurance Oregon line (see Table 2-3). As with Global, Pioneer, and other Endurance Oregon Line sensors, these sensors are in the OOI Core Sensor List developed to satisfy the OOI science requirements. Meteorological sensors and near-surface ocean sensors are deployed at the slope and mid-shelf sites. Meteorological sensors are deployed to resolve first order cross-shelf gradients in surface heat and momentum fluxes (including wind stress curl and cross-shelf diurnal wind variability). Upper ocean sensors will be deployed at these buoys and at the inner-shelf site to resolve cross-shelf gradients in water properties including nutrients and ocean color. The in situ measurements provided by these buoys will be an important source of ongoing improvement of algorithms for satellite estimation of wind stress and ocean color near the sea-land boundary. The moored profilers and bottom-mounted ADCP’s are the primary tools for time-series monitoring of the water column, providing interdisciplinary observations resolving the semi-diurnal tidal band and below. Sampling with the six Endurance Coastal Gliders will overlap directly with the higher frequency fixed node observations above in Table 2-7.

3.1.3 Endurance Array Washington Line VariantUpScope Technical Approach The backbone of Endurance Washington Line VariantUpScope, matching the Endurance Array Oregon Line Variant design, will be three fixed sites aligned perpendicular to isobaths and spanning from offshore (500 m), mid-shelf (80 m) and inshore (25 m) regimes offshore of Grays Harbor, Washington (Figure 3-2). The offshore and shelf sites combine fully-instrumented surface platforms with cabled profilers and benthic boundary layer sensors. The inshore site combines a wave-hardened surface platform electromechanically linked to benthic boundary layer sensors and a stand-alone winched profiler. The three environments are linked physically, biologically, and geologically, yet represent distinctly different processes. As an example, wave forcing is especially important at the 25 m site, while local and remote wind forcing is dominant at the mid-shelf site and slope currents and offshore mesoscale variability is important at the slope site. The offshore and shelf sites will include cabled infrastructure which integrates the Endurance Array with the Regional Scale Nodes through an extension from RSN Node 4A (Figure 3-4).


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Figure 3-2. Schematic diagram of the Endurance Array VariantUpScope, representative for both Endurance Washington Line and Endurance Oregon Line.

The additional cabled infrastructure of the VariantUpScope Endurance Array will require a modification to the Interface Agreement with the RSN but will continue to use the same physical interfaces, command control, and data transport mechanisms as other RSN components to minimize duplicated design work by RSN, CI or CGSN. The cabled infrastructure will support an extensive suite of core sensors deployed on winched profilers and at benthic boundary layer nodes. Equally important, the cabled infrastructure will also provide outstanding access for the science user community, enabling experiments requiring high-power, high-bandwidth sensors. Surface moorings will also be present at the 500 m and 80 m sites. These moorings will provide continuous meteorological and near-surface oceanographic measurements. The high-level functional block diagram for the VariantUpScope (Figure 3-3) shows the relationships among CGSN elements as well as the relationship of CGSN elements to RSN (red) and Cyberinfrastructure (CI) (green).


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CGSN Operation & Management Centers

Data Flow

02-21-2009 3502-10001-11-A

WHOI O&M Center SIO O&M Center OSU O&M Center

Surface Mooring

GI01SUMO

Hybrid Mooring

GI02HYPM

Mobile AssetsGI05MOAS3-Gliders

Irminger Array (GI)

IRM Flanking Mooring AGI03FLMA

IRM Flanking Mooring BGI03FLMB

Central Surface Mooring

CP01CNSM

Inshore Surface Mooring

CP03ISSM

Inshore Winched Profiler

CO03ISWP

Offshore Surface Mooring

CP04OSSM

Offshore Profiler Mooring

CP04OSPM

Upstream Inshore Profiler

MooringCP02PMUI

Upstream Offshore

Profiler MooringCP02PMUO

Mobile Assets

CP05MOAS4-Gliders 3-AUVs

Pioneer Array (CP)

Central Winched Profiler

CP01CNWP

Central Inshore Profiler Mooring

CP02PMCI

Central Offshore

Profiler MooringCP02PMCO


CE01ISSM


CE04OSSM

Shelf Surface Mooring

CE02SHSM

Mobile Assets

CE05MOAS6-Gliders

Offshore Hybrid Profiler

MooringCE04OSHY

Endurance Array (CE)

KeyIridium Rudics (LS)Fleet (HS)LAN CabledRecovered Assets

NOAA Surface Mooring

GP01SUMO

Mobile AssetsGP05MOAS

3-Gliders

Hybrid Mooring

GP02HYPM

Station Papa Array (GP)

Flanking Mooring A

GP03FLMA

Flanking Mooring B

GP03FLMB

Cyber Infrastructure

UW O&M Center

Surface Mooring

GS01SUMO

Hybrid Mooring

GS02HYPM

Flanking Mooring A

GS03FLMA

Flanking Mooring B

GS03FLMB

Mobile AssetsGS05MOAS

3-Gliders

55 South Array (GS)

3 3

67

3

242 2

User Community

2

Offshore Benthic Package

CE04OSBP

Shelf Winched Profiler

CE02SHWP

Shelf Benthic Package

CE02SHBP


CE01ISWP

Inshore Benthic Package

CE01ISBP

Endurance OREndurance WA

Surface Mooring

GA01SUMO

Hybrid Mooring

GA02HYPM

Flanking Mooring A

GA03FLMA

Flanking Mooring B

GA03FLMB

Mobile AssetsGA05MOAS

3-Gliders

Argentine Basin Array (GA)

3


CE06ISSM


CE09OSSM

Shelf Surface Mooring

CE07SHSM

Offshore Hybrid Profiler

MooringCE09OSHY

Offshore Benthic Package

CE09OSBP

Shelf Winched Profiler

CE07SHWP

Shelf Benthic Package

CE07SHBP

Inshore Benthic

PackageCE06ISBP


CE06ISWP

Figure 3-3. High-level functional block diagram of the VariantUpScope CGSN.

In the VariantUpScope design, the technical approach for Endurance Array Washington Line would match the Endurance Oregon Line technical approach (the latter is fully described in the OOI Final Network Design document [OOI Document Control Number 1101-00000]) and subject to the changes to the Variant design, described in section 2.3.3.4 above.


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3.2 Regional Scaled Nodes – VariantUpScope Description

In the VariantUpScope design, the Hydrate Ridge and Axial Seamount Sites remain unchanged from the FDR Baseline design (Figure 2-9). Similar to the Variant, all primary and secondary infrastructure at the Blanco Transform Fault Site is removed. The Subduction Zone Site would support a Primary Node (4A) with no instrumentation. Cabled infrastructure is added upslope to connect with the Endurance Washington moorings. In this option, similar to the Endurance Oregon Line, the cable would support a Coastal Scale Primary Node at 500 m with a Hybrid Mooring (Primary Node 4B), an unpopulated Coastal Scale Primary Node at 150 m (Primary Node 4C), and a Low Voltage node (Low Voltage Node 4C) that supports a mooring at 80 m (Figure 2-9). In the VariantUpScope, the Mid-Plate Site serves as a junction node to support the Endurance Washington line rather than the Warrenton shore station of the FND Baseline. No science sensors would be installed at the Mid-Plate Site. The VariantUpScope design has the same reduction in seafloor sensing capability at the time of OOI construction as in the Variant (see Table 2-6). The VariantUpScope option does, however, possess immediate expansion capability for sensor additions at the unpopulated nodes. The high-level block diagram for VariantUpScope is shown in Figure 3-5.

Figure 3-4. The proposed VariantUpScope (labeled Option 2) showing loss of cabled infrastructure at the Blanco Transform Fault and loss of all science sensors at the Mid-Plate Site. In this scenario, a full capability expansion port on the Mid-Plate Primary Node 5A is used to support the backbone cable to the Subduction Primary Node 4A. Similar to the Variant, no science is supported at Primary Node 4A (water depth ~ 3000 m). Node 4A supports an extension cable for Coastal Scale cabled Nodes at 500 m (Primary Node 4B), 150 m (Primary Node 4C), and 80 m (Low Voltage Node 4C).


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Figure 3-5. The high-level block diagram for the VariantUpScope (labeled Option 2) showing the RSN Infrastructure and the Primary and Secondary Infrastructure associated with the Endurance Array Lines off Oregon and Washington. Components shown in red are those removed from the 2008 FDR Baseline design.


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4 Comparison of Network Configurations

As outlined in Section 1 of this addendum, the overarching science themes of the OOI capture a large number of specific, compelling science questions. These thematic clusters of questions have motivated the community to contribute time and ideas toward the development of an observing network robust enough to provide core data from reliable sensors for 25-30 years and beyond (Baker et al. 2007, Wunsch 2008), yet flexible enough and powerful enough during its lifetime to permit the incorporation of new sensors and technologies not yet imagined. Fundamental to that goal are increases in the power and bandwidth available at observing platforms, multidisiciplinary observations of key processes at the seafloor and throughout the water column across time scales that capture variability from episodic events to decadal modes, and the sampling of regimes critical to improved understanding of the ocean. The transformational capability of high power and bandwidth for 20-30 years of ocean science research, the occupation of key high latitude and boundary current sites, the resolution in three-dimensional space and time of key processes, and the open access to all data with as much as possible in real time have been foundations for designing an observing system that can meet science objectives for decades to come, well beyond the lifetime of particular science questions. Unfortunately, fiscal constraints over the past few years have required the ocean sciences community and the OOI project team to work through different reductions in scope, each of which resulted in adjustments to the OOI network design and its sensing capabilities. The fundamental principles of expandability and transformational opportunity, however, have always guided these reductions in scope. The OOI network represented by the FND Baseline is the product of that evolutionary process, and was judged by the Final Design Review (FDR) panel in November 2008 to be ready for construction beginning in July 2010.

With these perspectives on the evolution of the OOI, we now can evaluate a Variant of the FND Baseline that increases the spatial coverage and number of observing assets at the global and coastal scales while reducing the spatial coverage, the number of observing assets, and future expansion capabilities at the regional scale and over the Juan de Fuca plate. In this section of the addendum we will discuss the relative contribution of these network changes to the science objectives of the OOI.

4.1 Science Gains and Losses in the Variant and VariantUpScope designs

4.1.1 Gains

4.1.1.1 Global Scale Capabilities

The Variant design, relative to the FND baseline, adds a deep ocean mooring in the Argentine Basin, and increases the number of sensors at Global nodes from 231 to 301. Many of the upper ocean sensors at the Global nodes will be involved in the two-dimensional detection of physical, chemical, and biological properties under time-varying forcing by wind, sun, turbulence, and vertical gradients in horizontal advection. At the end of the OOI construction phase nearly all of these measured properties at the Global nodes will be relevant to the assessment of climate change, carbon cycling and ocean acidification. Of particular importance will be the assessment of air-sea fluxes (energy, mass, gases, etc). The capabilities of each individual Global node remain largely unchanged from the FND Baseline under the Variant and VariantUpScope designs, but the OOI would gain improved spatial coverage of ocean processes under these designs relative to the FND Baseline.

The addition of measurement capabilities at a second Southern Hemisphere node (Argentine Basin) would provide valuable contrasts to the data obtained at the other southern node (55o S, 90o W) in the Pacific. The Argentine Basin displays unique air-sea interactions, physical oceanographic conditions, as well as distinct biogeochemical and carbon cycling. It contrasts markedly with the other three Global OOI sites due to a very dynamic and energetic environment, resulting from the confluence of major current systems and pronounced fronts, the influence of the Circumpolar Current, and topographic effects from strong seafloor bathymetry. The atmospheric forcing in this region cannot be quantified and modeled correctly due to insufficient data, and surface heat flux estimates based on existing data may be biased by the strong effect of oceanic fronts. Global maps of sea surface height (SSH) variability show a maximum in the Argentine Basin matched only by the Gulf Steam and Kuroshio extension regions and


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the Circumpolar Current itself. Such SSH variability has strong impacts on regional biogeochemical fluxes as well as on ecosystem dynamics.

Figure 4-1. Patterns of sea-surface CO2 (left, Gruber et al. 1996) and vertically-integrated CO2 inventory (right, Sabine et al. 2004). Note the distinct differences between the inventories in the Northern and Southern Atlantic, in contrast to the relative similarities in surface values.

Global maps of CO2 flux and surface anthropogenic CO2 display regionally elevated values in the Argentine Basin, yet column integrated anthropogenic CO2 is low (Figure 4.1). This points to a different set of dynamics at work in comparison to the deep downward mixing of surface water by convection as seen at Irminger Sea, and highlights the importance of this region for understanding and monitoring the processes which govern the ocean’s role in the global climate and carbon system. The Argentine Basin node would be located within a band of relatively high chlorophyll and primary productivity that extends eastward toward Africa. These conditions contrast strongly with known conditions at the 55oS Global node west of Chile. In contrast with the eastern section of the south Atlantic, there is evidence in the Argentine Basin that deep water mineralization processes do not correlate with organic matter flux from the surface (Hensen at al. 2000). Extended observations of physical forcing and biogeochemical cycling at the Argentine Basin site could address key hypotheses about the degree of coupling of deep ocean processes with surface processes, as well as those hypotheses about controls of productivity, including those involving aeolian deposition of micronutrients.

The addition of a fourth Global node enhances the capability of the OOI to address a wide range of science questions under three of the overarching themes (Ocean –Atmosphere Exchange; Climate Variability, Ocean Circulation, and Ecosystems; and Turbulent Mixing and Biophysical Interactions).

4.1.1.2 Coastal Scale Capabilities

The Endurance Line (44.6oN, offshore of Newport, OR) in the FND Baseline is designed to study the strong across-shelf and vertical gradients in coastal ocean properties, and the accompanying variations in marine ecosystem response. By cabling the line from the continental slope (500 m) to the mid shelf (80 m), high power and data bandwidth are available for real-time study of ocean and atmosphere processes. Real-time data allows for adaptive sampling on not only the OOI infrastructure, but can trigger rapid-response, intensive studies by a wide range of ocean observers users on a variety of phenomena e.g., harmful algal bloom (HAB) outbreaks, hypoxia events, and arrival of El Niño. By providing high power and bandwidth to the seafloor, sophisticated ocean laboratories can be established. For example, benthic laboratories with a variety of physical, chemical and biological instruments can be installed on the shelf seafloor. Such instruments can include turbulence sensors, mass spectrometers, scanning lasers, and phyto- and zooplankton imagers. To sample along-shore gradients in coastal ocean properties, a set of five cross-margin lines spanning over 500 km in the along-shore direction will be occupied by autonomous underwater gliders (Figure 2.3-3). These gliders will carry a key subset of the sensors used on the Endurance Array and extend the spatial footprint of the mooring array.

The Variant design provides enhancement of the Endurance Array by adding moorings off the central coast of Washington at the latitude (47o N) of Grays Harbor, WA. As illustrated and explained in the technical description (Figure 2.3-4), the distribution of moorings at 47o N would mirror the mooring line


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planned for 44.6o N, off Newport, OR. In contrast to cabled moorings at 80 m and 500 m on the Oregon mooring line, the Variant design would use high-power fuel cells in the surface buoys as power sources at the 80 m and 500 m sites on the Washington line (as will be used within the Pioneer Array).

While the Washington continental shelf is affected by similar wind forcing as the central Oregon shelf, it is more strongly influenced by the Columbia River outflow. As recent studies have shown (Hickey and Banas 2008), the presence of low-salinity water, combined with advection of high-nitrate water onto the Washington shelf, stratifies the water column and favors increased primary production. In the Variant, the combined observing assets of the central Oregon and Washington lines establish the PNW Endurance Array as a flexible and extendable ocean laboratory for comparing and contrasting the property distributions and processes in these two shelf environments. The continuous sampling will address climate variability and its associated impacts on marine ecosystems, including ocean health, carbon cycling and ocean acidification. Because many productive coastal regions around the world are wind driven and have a strong land-ocean connection, including the Washington line within the Endurance Array will make OOI results more extensible to other shelf environments around the world. The synergy of the two Endurance lines, separated by 265 km, will lead to increased understanding of mesoscale responses to variable forcing. This synergy would not be possible to characterize using one mooring line in isolation.

Many of the basic science goals of the PNW Endurance Array will be enhanced by having measurements at more than one along-shelf location. These measurements include changes in ecosystem response due to changes in atmospheric forcing (altered seasonal winds, changes in total wind forcing, different amount of precipitation or evaporation) or altered river input. Changes in these forcings, as modulated by climate variability, will result in changes to coastal ocean stratification and hence to the coastal ecosystem. On top of these local effects will be changes in remote forcing, for example by interannual variations introduced by El Niño, or interdecadal changes due to Pacific Decadal Oscillation (PDO). Two specific examples of the importance of measuring and understanding alongshore variability and remote forcing are as follows. The appearance of extreme hypoxia and marine life die-offs during the summer of 2002 off central Oregon was connected to advection of anomalous water properties from the Gulf of Alaska and west wind drift into the northern California Current (Grantham et al., 2004; Freeland et al., 2003). The occurrence of shellfish closures along the Washington coast is related to the advection of harmful algae into those regions from seed populations in oceanic features elsewhere along the coast (Trainer et al., 2002, Trainer et al., 2009). In particular, it appears that HAB occurrence along the Washington coast is associated with advection of plankton northward from the central Oregon region during periods of wind relaxation or reversal.

While the PNW Endurance glider array will provide much information about along-shore gradients and the ability of gliders to carry ever-more sophisticated sensors is improving, they cannot substitute for the high power and high data bandwidth capabilities of fixed and vertically profiling moored sensors. Since the Endurance Washington line mooring sites are located at the same depths (25, 80, 500 m) as the Endurance Oregon Line, a direct comparison between these locations is possible. The combination of the Washington and Oregon lines will vastly increase the relevance of the OOI to coastal ecosystems globally. The two shelves are forced by similar regional upwelling winds, but are far enough apart (approximately 265 km) to have significant gradients of ecosystem response. These mooring lines are well positioned to observe processes and features thought to influence coastal productivity worldwide such as varying shelf width, varying wind stress, banks, canyons, and fresh water input.

The addition of moorings across the Washington shelf-slope enhances the capability of the OOI to address science questions within three of the thematic areas: Climate Variability, Ocean Circulation, and Ecosystems; Turbulent Mixing and Biophysical Interactions; and Coastal Ocean Dynamics and Ecosystems.


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4.1.2 Justification for a cabled Endurance Array Washington Line In the VariantUpScope design, the 80m and 500m moorings along the Endurance Washington line would be attached to cable from the Subduction Zone node, just as the moorings at those same depths along the Endurance Oregon line are cabled to the Hydrate Ridge node. The high power and bandwidth provided at the 80- and 500-m sites permit a more extensive set of ocean observations than can be reported to shore in real-time. For example, benthic laboratories with a variety of physical, biological, chemical,and geological instruments (turbulence sensors, mass spectrometers, scanning lasers, and phyto- and zooplankton imagers) would be possible. The configuration of this line would be comparable to the cabled line off Oregon (Figure 4.2).

Figure 4-2. Schematic diagram of the components linking a primary node at Hydrate Ridge with the Endurance Line off Oregon. A detailed description of this configuration can be found in Section 4.3.3.7 of the FND. This configuration would be replicated at 25, 80, and 500 m off Washington under VariantUpScope design.

On annual and interannual time scales, there is differential influence of the Columbia River plume on sediment deposition on the Washington and Oregon shelves, both in the spatial pattern of sediment deposition and duration of deposition episodes. Placing instruments and benthic laboratories at a cabled 80-m site on the Endurance Washington line would provide an ideal, and real-time, benthic laboratory contrast to the cabled 80-m mooring on the Endurance Oregon Line.

Although considerable interannual variability has been detected in the distribution and abundance of plankton in the Northeast Pacific, strong correlations of plankton species patterns with PDO dynamics suggest that climate variability is expressed within patterns of plankton species abundances and assemblages. Such parameters are important for long-term assessment of ecosystem health. Recent advances in optical and acoustical imaging permit, under sufficient power and bandwidth conditions, direct real-time observation of plankton interactions. Cabled moorings in the Endurance Array will support the ability to image phytoplankton and zooplankton communities at specific sites across the shelf, documenting responses to time-varying wind forcing, advection and nutrient availability. Of particular importance will be the comparison of population responses north and south of the Columbia River outflow, and the role of decadal variability in forcing on the population response. It is also important to characterize the cross-shelf gradients in ecosystem dynamics expressed by the propensity for zooplankton to concentrate near the shelf break where they can avoid daytime predation by vertical


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migration out of the lighted zone. Once again, the increased power and bandwidth from a cabled Endurance Washington Line would complement this transformational technology on the cabled Endurance Oregon Line, again contributing to the whole being greater than the sum of the parts.

The important measurements in coastal ecosystems, those that will fundamentally transform our understanding of and our ability to model the ecosystem, will be made by the optical, biogeochemical, acoustic, and eventually genomic measurements enabled by cabling. Moreover, the interacting systems, particularly those involving zooplankton and fish, change over short timescales. Carbon export from the highly-productive shelf to potential burial in the abyss will also be better studied with the two shelf lines and the water column moorings on the Hydrate Ridge node, because it facilitates a control volume in which to evaluate carbon export across the shelf break.

In effect, the two Endurance lines will be continually performing paired experiments, with similar large-scale climatic forcing but subject to local variation of parameters such as stratification. These experiments will be vastly more meaningful when cutting-edge observational technology, enabled by cabling, is used at both sites.

In summary, the addition of a cabled mooring line at 47oN to the Endurance Array enhances the capabilities of the OOI to address science questions within four of the thematic areas: Ocean-Atmosphere Exchange, Climate Variability, Ocean Circulation, and Ecosystems; Turbulent Mixing and Biophysical Interactions; and Coastal Ocean Dynamics and Ecosystems.

4.1.3 Losses As summarized briefly in Section 1 of this Addendum, the most important negative consequences of the Variant design are seen in the

• significant loss of scientific capability in the thematic areas of Plate-Scale and Ocean Geodynamics and Fluid-Rock Interactions - Subseafloor Biosphere, and

• severe loss of power, bandwidth, and system expandability over the 20-30 year life of the OOI.

We elaborate on these consequences in the paragraphs below.

4.1.3.1 Loss of Science Capability

The science questions clustered within the OOI thematic areas, along with the transformative capacity of the seafloor cable, provided the motivation for an observing system with many assets centered over the Juan de Fuca tectonic plate. Input from multidisciplinary working groups led to the choices of sites which had unique plate boundary and water column characteristics. The comparisons of processes along plate boundaries, as provided by the Blanco Transform Site and the Subduction Zone site, illustrate the compelling, long-term science to be done in this region.

The Blanco Transform Site is a major foundation of the OOI Science Theme of Plate-Scale Ocean Geodynamics and is an important component in two other Science Themes: Fluid-Rock Interactions and the Subseafloor Biosphere and Climate Variability, Ocean Circulation, and Ecosystems.

Tectonic plates are the fundamental building blocks of our planet, with the three major plate boundaries defined as subduction zones, mid-ocean ridges, and transform faults. The OOI node at the Blanco Transform Fault would be the only site in the world’s ocean enabling the study of an oceanic transform fault in real time. Oceanic transform faults are natural laboratories for earthquake physics due to the relatively simple geological and geometrical structure of these faults. Undersea cable (data and power) to this site is required to minimize instrument drift, to maintain accurate and precise timing of the sensors, and to conduct adaptive sampling in response to events at this site and at other nodes.

The Blanco Transform fault observatory would be the first to provide long-term measurements of seismicity, and fault-zone fluid discharge over multiple earthquake cycles along this important plate boundary. This would allow separation of the effects of geological heterogeneity from stress-state, a fundamental tradeoff that limits studies of continental faults with longer recurrence intervals. Moreover, owing to the well-characterized plate-tectonic boundary conditions and compositional uniformity of oceanic lithosphere, vis-a-vis the thicker, more complex continental crust, the seismogenic properties of the Blanco Transform can be directly compared to realistic geodynamic models of fault thermal structure


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and seismogenesis. It is impossible to study plate-scale issues without knowledge of the tractions on all types of plate boundaries.

The geological history of this site makes it particularly relevant to seismic studies because the Blanco Ridge segment has ruptured five times since 1967 with magnitude (M) 6.1–6.5 earthquakes. It is likely that multiple M6 earthquakes would be recorded over the 30-year life span of the OOI. Such a dataset would greatly enhance the data now available in the earthquake science community. The seismic experiment laid out for Blanco in the FDR Baseline design would allow significant advances in understanding the basic physics of earthquake rupture by utilizing the unusually short recurrence interval of magnitude 6–7 earthquakes. The Blanco transform fault is the only site in OOI where we would regularly capture large earthquakes.

The Blanco site also provides an opportunity to test the scales over which large earthquakes impact the hydrogeology of the oceanic crust, which is the largest fractured aquifer on our planet. In conjunction with observational capabilities within NEPTUNE Canada, the Blanco instrumentation would allow the first observations of changes in fluid-flow transients, pore-fluid pressure, and temperature and volatile output as a result of large oceanic earthquakes.

The water column at this site is strongly influenced by the southward flowing California Current and reflects the decadal-scale impacts of the PDO and El Niño/La Niña. In addition, this site is critical to addressing Flow over Rough Topography, which is a component of the OOI Science Theme, Turbulent Mixing and Biophysical Interactions. The deletion of the Blanco node represents a reduction of potential capability of the OOI for turbulence and other flow-topography interaction studies. Furthermore, the loss of the Blanco node eliminates the potential for examination at this site of biogeochemical processes associated with time-varying horizontal gradients in nutrient-depleted offshore waters and nutrient-replete coastal waters caused by fluctuations in the offshore extent of the California Current.

The Variant design also removes the Subduction Zone node and instrumentation from the OOI. This site is located seaward of the Cascadia deformation front and was chosen in response to numerous community request for assistance (RFA) proposals that addressed: 1) linkages among ocean dynamics, climate change and ecosystem response from basin to regional scales; 2) seismic observations of the Cascadia continental margin directed towards an effective real-time earthquake and tsunami warning system; and 3) understanding plate scale seismicity and hydrological connectivity.

The Cascadia Subduction Zone off Washington and Oregon has generated historically enormous (Mw 9+) earthquakes and devastating tsunamis. While is it not currently possible to predict when the next significant rupture event will occur, it has been 309 years since the last great Cascadia rupture and enough strain has accumulated to trigger another devastating event. The most common interval for earthquakes to occur in this area is every 200-400 years. The rupture zone of the Sumatra-Adaman Islands (the site of the December 26, 2004 magnitude 9.3 earthquake) is comparable in size to the Cascadia Subduction Zone. At this time there are no telemetered seismometers above the locked zone even though recent modeling results indicate that coastal communities could receive as much as 5->30 seconds warning were such a system to be in place. In contrast Japan has eight cabled arrays of seafloor seismometers already installed or under construction above the great subduction zone region off its coast (McGuire et al. 2008), where the largest event anticipated is <30 times that likely to be observed in Cascadia.

In addition to its importance as the beginning of an early seismic warning system, this site was also chosen (in conjunction with the Hydrate Ridge Site) because recent models predict that forearc segments characterized by gravity lows and deep basins should be locked during inter-seismic periods, while areas of gravity highs are actively undergoing creep. Larger earthquakes tend to nucleate at boundaries between gravity highs and lows, and then propagate across the lows. It has been found that periodic episodes of slip occur on the plate boundary downdip from the locked zone at a remarkably regular interval of 14 months (Rogers and Dragert, 2003). Recent results from EarthScope and other programs indicate that this region slipped three times in 2007-2008. There is some controversy about whether these events represent a change in the fault behavior or if the previous pattern (longer intervals) was an artifact of poor sampling. Longer time series combined with modeling studies are needed to determine whether changes in episodic tremor and slip patterns can be used to anticipate when the locked zone is approaching failure.


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The science of strain transients on multiple time scales (ie. the relationship between earthquakes and newly recognized slow strain transients manifested as slow earthquakes, seismic tremor, and GPS slip events) is currently one of the hottest topics in Earth science and is a major focus of both the EarthScope and MARGINS programs. Both of these programs have identified better coverage of continental margins as an important objective. Because EarthScope instrumentation is on the continent, seafloor seismometers can provide a better focus on the locked zone beneath the continental shelf, slope and outer accretionary complex off Washington and Oregon where the next big Cascadian earthquake and tsunami will occur. This capability would be lost under Variant and VariantUpScope designs.

The Variant design also removes the instrumentation from the Mid-Plate node. The seismometers were placed there to understand stress propagation across a plate as well as intraplate deformation and its relation to plate boundary. This capability would be lost under Variant and VariantUpScope designs.

In summary, both the Variant and VariantUpScope designs result in significant loss of scientific capability in the thematic areas of Plate-Scale and Ocean Geodynamics and Fluid-Rock Interactions - Subseafloor Biosphere.

4.1.3.2 Loss of capabilities for expansion

One of the most transformational characteristics of the OOI is the cabled system that can deliver unprecedented, sustained levels of electrical power and high bandwidth communications, for decades, over a volume the size of mesoscale ocean processes, or a tectonic plate (100’s of km on a side). An important and critical strength of the multi-segment cable design is that it has extensive expansion capabilities, both in terms of its footprint and its flexibility to incorporate vast sensor arrays, robotic benthic rovers, or complex water column moorings. These features will provide the next generation of ocean scientists with the infrastructure to design and deploy innovative sensing modalities, conduct real-time, interactive experiments, and develop tools for responding to and quantifying previously inaccessible processes that unfold rapidly or take decades to occur.

As stated in Section 1 of this Addendum, one of the guiding principles of the network design of OOI was the long-term capacity to support innovative observing tools, especially those sensors and techniques that we cannot yet imagine. It is relatively easy to expect the migration of complex bench-top instruments like mass spectrometers, gas chromatographs and flow cytometers to undersea configurations within the next few years, but only if sufficient power exists. New technologies never begin testing and development in low power configurations, and undersea cabling enhances the opportunity for innovative technology to be employed much sooner in moored and seafloor experiments than could occur without the power and bandwidth provided by cable. Table 3.1 provides examples of power and bandwidth for moorings, as well as for biological, chemical, and acoustic sensors on the cabled infrastructure and which can be added in the future.

Table 4-1. Power and Bandwidth Expandability Examples

†On the RSN system in the FDR baseline design; future sensors anticipated to be added

It is important to note that the transformative capacity of telecom cables offers the ability to provide power to moored profiling systems, enabling longer, more continuous and more frequent operation, as reflected by the water column moorings at the Hydrate Ridge and Axial Seamount nodes and at the 500 m and 80 m mooring sites within the Endurance Array. Prior to the Preliminary Design Review, this capability was expressed by having full water-column moorings at all five seafloor cabled nodes. The FND Baseline

Primary Nodes

RSN Mooring

CGSN Uncable Mooring

In situ Flow

Cytom

High Definition Camera +

lights† Echo

sounder

Raman Spectrometer

Hydro phone†

Acoustic thermometry

ADCP†

Power 10 kW 3500 W contin.

250 W contin. 50 W 300 W 40 W 75 W 1.2 W 50W

contin. 60 W trans

Bandwidth 10 Gb/s 1000 Mb/s 100 kb/s 1.5 Mb/s 1.5 Gb/s 4.6 Mb/s 100 kb/s 12 Mb/s 256 kbps 100 kb/s

Expanda-bility

60% FDR configura-

tion 30 % < 5%


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OOI # of Sensor Types by Discipline(Unchanged between FDR baseline and Variant designs)

Chemical 22

Biological 26Physical 29

Geological 18

configuration of water-column moorings at only Hydrate Ridge and Axial Seamount reflects a budgetary decision, not a scientific decision. Each primary node has more than enough power and bandwidth to support the full array of seafloor instrumentation and a water-column mooring.

In addition to having capabilities for the addition of new sensors, the segment design of the cable and 10 kW primary nodes also allows for 100 km extension cables to be added to the system to address multidisciplinary science and linkages among processes operating at the spatial scale of the Juan de Fuca plate and throughout the overlying ocean.

The high power and bandwidth provided by cable may also be important for addressing biofouling issues associated with lengthy deployments through the use of ultrasonic or UV radiation techniques.

In summary, the Variant and VariantUpScope designs result in significant loss of fundamental seafloor science and a drastic loss in the future expansion capability for the OOI.

4.2 Sensing capability of the OOI under Variant and VariantUpScope

The sensing capabilities and sensor distributions within the CGSN and RSN components have been described for the FND Baseline in the parent document to this Addendum, in Sections 4.3 and 4.4, respectively. Additional details about the distribution of core sensors on specific moorings and platforms within the Variant and VariantUpScope designs can be found in Section 2 of this Addendum. No sensor types have changed since the Final Design Review. However, the proposed changes to the network configurations under the Variant and VariantUpScope designs result in an increase in the total number of sensors deployed on the infrastructure.

It is important to note that the distribution of sensor types to be deployed during the construction phase of the OOI is quite evenly spread across the oceanographic disciplines (Figure 4.3) in all the designs. Many sensor types, such as CTDs and ADCPs, provide data that can be used by multiple disciplines in addressing specific questions.

More core sensors would be used by the biological, chemical, and physical, disciplines under the Variant design, while the loss of fifteen seismometers decreases the sensors used by the geological discipline (Figure 4.3).

Figure 4-3. OOI core sensor types by discipline.


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The distribution of sensors in the FDR Baseline design is shown in Figure 4.4a, while the Variant distribution is shown in Figure 4.4b. Note that the proportional distribution between biological, chemical, and physical changes little, even though the absolute numbers of sensors would increase. The geological component, however, loses nearly half of its sensor capacity under the Variant design (Figure 4.4c).

These sensor distribution patterns change very little between the Variant and VariantUpScope designs.

It is also important to note that the depth distribution of sensors in each of these designs has been optimized for the detection of key parameters for the detection of climate signals, pCO2, carbon, nutrients, as well as the atmospheric and physical forcing parameters. The proportional distributions of those sensors do not change in the Variant or VariantUpScope design, but the numbers of relevant sensors increases in those designs relative to the FND Baseline.

Figure 4-4. a) FND sensors by discipline, b) Variant sensors by discipline, c) Percent change by discipline from FND Baseline to Variant.

OOI # of Core Sensors Representing DisciplinesFDR Baseline

Biological 122

Chemical 140

Geological 32

Physical 317

OOI # of Core Sensors Representing DisciplinesVariant Design

Biological 159

Chemical 184

Geological 17

Physical 396

Percent Change in number of sensors from FDR baseline to Variant design

-60 -50 -40 -30 -20 -10

0 10 20 30 40

Bio Chem Geo Phys

Primary Science Discipline

Perc

en

t ch

an

ge

4-4 b

4-4 c

4-4 a


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4.3 Future Opportunities

The OOI has never been viewed as a research program, but as an innovative, linked, spatially-distributed, and technically-advanced architecture that could support decades of creative research while providing continuous core data in a rich spatial and temporal context. Since its inception as an ocean observing infrastructure, there has been a long-term vision that the OOI would possess the capacity to extend beyond its initial capabilities at commissioning and stimulate the development of new ideas and research directions through regular funding pathways. Some of these future opportunities have been addressed within the Addendum. Others would include:

• the expanded use of autonomous assets and robotic devices as new power, network and software technologies are developed;

• further development of moored technologies over cabled nodes to expand the spatial coverage of the most advanced sensors for addressing climate, etc;

• extended spatial mapping with advanced genomic and proteonomic systems, on moorings and vehicles;

• resolution of elemental pathways through key biogeochemical processes using advanced in situ analytical sensors;

• application of new tools for earthquake and tsunami detection and geodesy;

• the use of acoustic thermometry for high temporal resolution of climate variables while averaging over basin scales.

This is not an exhaustive list of opportunities, but gives a sense of the growth potential for a well-designed infrastructure.

4.4 Summary

The technical components that comprise the baseline of the OOI have been extensively reviewed and approved as sound and ready for implementation. The network designs described in this Addendum represent alternative combinations of those approved technical components, all of which are linked by a sophisticated cyberinfrastructure for rapid, transparent dissemination of data to the scientific community, policy makers, students, educators, and the public. Each of these designs provides, to differing degrees, an observing infrastructure that will transform our approach to the compelling research topics facing society. Each design will be able to deliver scientific results during the implementation phase. Finally, each design provides its own path for future expansion and development by ocean and earth scientists over the next 20-30 years.


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