Terrestrial Snow Two Perspectives: NOAA Weather and Water Operations NASA Earth Science Research Don Cline Office of Climate, Water and Weather Services,

Terrestrial SnowTwo Perspectives:

NOAA Weather and Water OperationsNASA Earth Science Research

Don Cline

Office of Climate, Water and Weather Services, National Weather Service, NOAA

National Operational Hydrologic Remote Sensing Center

Cryosphere Theme

March 2-4 2005 2

Terrestrial Snow

IGOS First Cryosphere Theme Workshop Kananaskis, Alberta, Canada

Cryosphere Theme

• Protect, Restore, and Manage the Use of Coastal and Ocean Resources Through an Ecosystem Approach to Management

• Snowmelt is an important component of freshwater input to oceans

• Understand Climate Variability and Change to Enhance Society’s Ability to Plan and Respond

• Terrestrial snow is a sensitive indicator of climate change, a significant storage component of the global water cycle, and affects weather and climate through several surface energy and mass exchange mechanisms

• Several socioeconomic sectors linked to terrestrial snow

• Serve Society’s Needs for Weather and Water Information• Snow is a major component of water resources and contributor to flooding

• Support the Nation’s Commerce with Information for Safe, Efficient, and Environmentally Sound Transportation

• Terrestrial snow directly impacts land transportation

Operational Drivers: NOAA’s Four Mission Goals

March 2-4 2005 3

Terrestrial Snow


Cryosphere Theme

“The Value of Snow and Snow Information Services” (2004)

Winter tourism Exceeds $8B / yr

Cold water fishing (snow is cold water source)

Exceeds $2.3B / yr

Snowpack water storage Up to $348B / yr

Economic Benefits of SnowSnow removal Exceeds $2B / yr

Road closures that cause lost retail trade, wages, and tax revenue

Exceeds $10B / day

Flight delays $3.2B / yr

Damage to utilities Up to $2B / event

Flooding from snowmelt Up to $4.3B / event

Economic Costs of Snow

- Dr. Rodney Weiher, Chief Economist, National Oceanic and Atmospheric Administration, U.S. Dept. of Commerce

Operational Drivers: Snow Economics

March 2-4 2005 4

Terrestrial Snow


Cryosphere Theme

“The Value of Snow and Snow Information Services” (2004)

Winter tourism Exceeds $8B / yr

Cold water fishing (snow is cold water source)

Exceeds $2.3B / yr

Snowpack water storage Up to $348B / yr

Economic Benefits of SnowSnow removal Exceeds $2B / yr

Road closures that cause lost retail trade, wages, and tax revenue

Exceeds $10B / day

Flight delays $3.2B / yr

Damage to utilities Up to $2B / event

Flooding from snowmelt Up to $4.3B / event

Economic Costs of Snow

- Dr. Rodney Weiher, Chief Economist, National Oceanic and Atmospheric Administration, U.S. Dept. of Commerce

“… improved snow information and services have potential benefits greater than $1.3

billion annually.”

“… investments that make only modest improvements in snow information will have

substantial economic payoffs.”

Operational Drivers: Snow Economics

March 2-4 2005 5

Terrestrial Snow


Cryosphere Theme

1960 1970 1980 1990 2000195019401930192019101900

Snowmelt flooding affects thousands of lives and causes billions of dollars in damages.

Snow is critically important to the U.S.

1904: Grand Rapids, MI 1936: Pittsburgh, PA 1964: Oregon City, OR 1983 Salt Lake City, UT 1996: Harrisburg, PA

1907: Wheeling, WV 1927: Cairo, IL 1951: Mankato, MN 1979: Fargo, ND 1997: Grand Forks, ND

Major snow-related flood Top 20 most significant floods of 20th century (USGS; 9 of 20 were snow-related)

Region: MichiganCause: Rain on snow, Frozen SoilsDamage: 1 Death, $40 Million

Region: New EnglandCause: Snowmelt, Rain on snowDamage: 150+ Deaths, $3.9 Billion

Region: Pacific NorthwestCause: Rain on snowDamage: 47 Deaths,$2.4 Billion

Region: Colorado River BasinCause: Record Snow PacksDamage: $1.1 Billion

Region: Northeast U.S.Cause: Rapid SnowmeltDamage: 33 Deaths,$1.7 Billion

Region: West VirginiaCause: Heavy Rain on SnowDamage: $1.9 Billion

Region: Mississippi RiverCause: Saturated Soils & SnowmeltDamage: $2.4 Billion

Region: Southern MinnesotaCause: Rain on Snow, Rapid SnowmeltDamage: $21 Million

Region: Red River of the NorthCause: SnowmeltDamage: $96 Million

Region: Red River of the NorthCause: Snowmelt, Frozen SoilDamage: $5.1 Billion

(Damages in 2002 Dollars)

March 2-4 2005 6

Terrestrial Snow


Cryosphere Theme

Evolutionary infusion of new observing systems, data sources, science, and technology.

Comprehensive Analyses and Data Assimilation (including quality control,

multisensor estimation and 4DDA)

Products

Systematic Evaluation and Customer Feedback Data and Information Gap

Analysis (e.g. high space-time

resolution)

Existing Obs. Systems, Data Sources, S&T

New Obs. Systems, Data Sources, S&T

Conceptual Evolution of Operational Observing Systems

Requirements

Updated Requirements

March 2-4 2005 7

Terrestrial Snow


Cryosphere Theme

NOAA/NWS/NOHRSC National Snow Analyses (NSA)

Ground-based Snow Data

METAR, SNOTEL, CADWR, HADS, NWS

Co-op, Mesonets

Airborne Snow Water Equivalent

Satellite Snow Cover Data

GOES, AVHRR, SSM/I

NEXRAD Radar Data

Numerical Weather Model Data

Eta, RUC2

NOHRSC Database Management System

Data ingest, quality control, pre-processing

Data and Product Archive

NOHRSC Snow Data Assimilation System

Energy-and-mass-balance snow modeling and observed snow

data assimilation

1-km, Hourly

Continental U.S.

Product Generation and Distribution

Elements:

Daily National Snow Analyses:

• Water Equivalent• Snow Depth,

• Snow Temperature• Sublimation

• Condensation• Snow Melt

Formats:• Interactive Maps• Time-series Plots• Text Discussions

• Alphanumeric and Gridded products

Distribution:

NOHRSC Web Site, AWIPS, direct FTP,

NSIDC, NCDC

March 2-4 2005 8

Terrestrial Snow


Cryosphere Theme

• Comprehensive snow hydrologic information products• Snow water equivalent, depth, wetness, temperature, melt, sublimation losses

• GIS-based interactive information distribution on the Internet

• Overlay administrative and basin boundaries, rivers, roads, cities

• Zoom to full 1-km resolution

• Query stations for time- series history

• Export text data summaries for each basin

• Up to 300,000 hits a day during peak season

User Interactive Mapping on Internet

March 2-4 2005 9

Terrestrial Snow


Cryosphere Theme

Time-series History Queries on Internet

• SWE, Depth, Density, and Melt

• e.g. Washington DC (Reagan National Airport)

– Jan 15 - Feb 15, 2004

• Dark blue line show modeled SWE

• Light blue line shows modeled snow depth

• Light blue points show observed snow depth

• Assimilation of observed snow depth on Jan 27 corrected for underestimated snow precipitation

User can query any of 40,000 stations shown on interactive map.

March 2-4 2005 10

Terrestrial Snow


Cryosphere Theme

Hourly SWE Analysis, Oct 1 2003 – May 23 2004

March 2-4 2005 11

Terrestrial Snow


Cryosphere Theme

• We lack sufficient understanding of the magnitude and variability of snow water storage and of the fluxes and feedbacks that relate it to the atmosphere and climate necessary to reliably predict local-regional consequences of climate variability and change.

Science Drivers for Improved Snow Observations

• Snow water content is poorly measured by sparse and inconsistent ground networks.

• Current remote sensing observing systems are unable to provide process-oriented measurements of snow hydrologic properties required to test and constrain today’s predictive models.

• Fundamental questions such as how much water is stored locally, regionally, or globally in seasonal snow packs remain unanswered.

March 2-4 2005 12

Terrestrial Snow


Cryosphere Theme

In Situ Snow Observations

March 2-4 2005 13

Terrestrial Snow


Cryosphere Theme

Spaceborne Passive Microwave

Space-Time Scales of Snow Processes

Spatial Scale

Te

mp

ora

l S

ca

le

10m 100m 1km 10km 100km 1000km

1

10

100

1000

10000

100000

3 Days

1 Day

1 Week

1 Month

1 Hour

1 Year

2 Years3 Years

Te

mp

ora

l S

ca

le (

Ho

urs

)

10 Years

Interannual Variability in Snow Accumulation

(Variation in Synoptic Climate)

Snowmelt Floods

Snow Metamorphism Effects on Structural Proeprties and

Radiative Transfer

Intraseasonal Variability in Snow Accumulation

(Variation in Individual Storm Tracks)

Snow Melt Effects on Water Balance, Surface Energy Balance and Microwave Radiative Transfer

Enhanced Boundary-layer Stability over Snow

Wind-redistribution of Snow Accumulation on the Ground

Synoptic Storm Systems

(Snow Precipitation and Accumulation)

Orographic Precipitation Effects on Snow Accumulation

Effects of Snow Cover on Heat and Moisture Exchanges with Advecting Airmasses

March 2-4 2005 14

Terrestrial Snow


Cryosphere Theme

Comparison of Continental-scale Water Storage

March 2-4 2005 15

Terrestrial Snow


Cryosphere Theme




Products



resolution)




Requirements


March 2-4 2005 16

Terrestrial Snow


Cryosphere Theme

• Specified in NOAA Observing System Architecture (NOSA)• http://nosa.noaa.gov

• Four snow observation requirements:• Snow Cover• Snow Depth

– Shallow, Deep

• Snow Water Equivalent (on ground)– Shallow, Deep

• Snowfall Water Equivalent (precip rate)

• Two spatial domains:• North America• Global

• Two levels of requirements for each• Threshold (Minimal acceptable requirement)• Objective

NOAA Operational Observing Requirements

March 2-4 2005 17

Terrestrial Snow


Cryosphere ThemeNOAA Operational Observing Requirements

Domain

Spatial MeasurementTemporal

Horizontal

Resolution

Mapping

Accuracy

Range

Accuracy

Sampling

Interval

North America

T 500m 250m0-

100%10% 24h

O 100m 100m0-

100%5% 12h

GlobalT 500m 250m

0-100%

10% 24h

O 250m 100m0-

100%5% 12h

Snow Cover

Current Operational: GOES and AVHRR (Neither meets T spatial requirements)

Current Experimental: MODIS (Meets T spatial and measurement, but not temporal)

Planned Operational: GOES-R, VIIRS (Will meet all current T requirements)

March 2-4 2005 18

Terrestrial Snow



Domain


Horizontal

Resolution

Mapping

Accuracy

Range

Accuracy

Sampling

Interval

North America

T 500 m250 m

0-1 m 1-10 m

10 cm

10%

6 days*

O 100 m100 m

0-1 m 1-10 m

6 cm 6%

12 h

Global

T 500 m250 m

0-1 m 1-10 m

10 cm

10%

3 days*

O 250 m100 m

0-1 m 1-10 m

6 cm 6%

12 h

Snow Depth

Current Operational: SSM/I (Doesn’t meet T spatial or measurement requirements)

Current Experimental: AMSR (Doesn’t meet T spatial or measurement requirements)

Planned Operational: CMIS (Won’t meet T spatial or measurement requirements)

March 2-4 2005 19

Terrestrial Snow



Domain


Horizontal

Resolution

Mapping

Accuracy

Range

Accuracy

Sampling

Interval

North America

T 500 m250 m

0.0-0.3 m 0.3-3.0 m

3 cm 10%

6 days*

O 100 m100 m

0.0-0.3 m 0.3-3.0 m

2 cm 7%

12 h

Global

T 500 m250 m

0.0-0.3 m 0.3-3.0 m

10 cm

10%

3 days*

O 250 m100 m

0.0-0.3 m 0.3-3.0 m

2 cm 7%

12 h

Snow Water Equivalent

Current Operational: SSM/I, AMSU (Doesn’t meet T spatial or meas. requirements)

Current Experimental: AMSR (Doesn’t meet T spatial or measurement requirements)

Planned Operational: CMIS (Won’t meet T spatial or measurement requirements)

March 2-4 2005 20

Terrestrial Snow



Domain


Horizontal

Resolution

Mapping

Accuracy

Range

Accuracy

Sampling

Interval

North America

T 500 m250 m

0-3 cm/h

1 mm 1 h

O 100 m100 m

0-3 cm/h

0.5 mm

15 min

GlobalT 500 m

250 m

0-3 cm/h

1 mm 1 h

O 250 m100 m

0-3 cm/h

0.5 mm

15 min

Snowfall Water Equivalent

Current Operational: None

Current Experimental: Ground-based Doppler Radar (Neither spatial or measurement)

Planned Experimental: GPM (TBD)

March 2-4 2005 21

Terrestrial Snow


Cryosphere Theme




Products



resolution)




Requirements


March 2-4 2005 22

Terrestrial Snow


Cryosphere Theme

• Sponsored by Terrestrial Hydrology Program

• Identify and implement the relevant science, technology, and application infrastructure necessary to support a future remote sensing mission focused on Cold Land Processes.

• Snow on land, ice sheets and sea ice

• 15 workshops since 2000 (next Mar 23-24, 2005; Seattle)• Science framework for mission

• Technology development for experimental and operational missions

• Algorithm development

• Model development– Land surface (snow)

– Radiative transfer (microwave)

NASA Cold Land Processes Working Group

Enterprise Goals:

Understanddistribution ofsnowpack waterstorage and meltstate (wetness)

Models capable of predicting the water cycle,including floods and droughts,down to 10’s of km

Routine probabilisticforecasts of snowwater storage andsnowfall accurate enough to supporteconomic decisions

Improve winter stormhazard forecasting atlocal scales tosupport mitigation

Kn

ow

led

ge

Bas

e

• Various technology development needs detailed in ESTO database to support multi-frequency SAR, higher-resolution radiometers, larger data volumes, etc.

CLPX I

• Global variations in areal extent of snow cover well quantified• Poor understanding of how local-scale processes “scale up”• Poor understanding of snow feedbacks to atmosphere

• Models don’t account for sub-grid scale snow distributions• Winter precipitation poorly observed, esp. in high latitudes• Paucity of observations of snow water content or melt state

TODAY:

AMSR-E

• Improved general understanding of cold land processes

• Improved representation of fundamental cold land processes in regional-global models

SSM/I

• Evaluation of regional-global snow models, AMSR-E snow products

• Progress in microwave radiative transfer models for snow

CL

PX

II

• New algorithms for active/passive SWE and wetness retrieval

• Examine key questions unresolved by CLPX I – e.g. dynamics, untested snowpack regimes, polar regions, sea ice, etc.

• Test and refine improved models and data assimilation

• Test and refine new active/passive algorithms with augmented Ku-band AIRSAR

CLPPTechnology

Devel.CLPP Technology Development

Data Analyses

• Improved strategies for assimilation of snow information in models

CMIS (NPOESS)• Continuation of 30-year baseline of global monitoring of snow cover and depth (dry-snow only, coarse resolution passive microwave)

• Narrow-swath sampling of global snow Narrow-swath sampling of global snow water equivalent and snow wetnesswater equivalent and snow wetness

• Full global measurement of snow Full global measurement of snow water equivalent and snow wetnesswater equivalent and snow wetness

• “Routine” modeled estimates of global SWE and snow wetness, largely unconstrained by observations

CLP Measurement Technology Development

• Improved measurement accuracy and precision

• Higher spatial and temporal resolution to resolve precipitation from individual storms

2002 2010 2012 2014 20162006 20082004

• Data collection as needed to support advanced CLPP preparations – algorithm refinement, ground system testing, science data processing tests, etc.

CLPP Education and Outreach

CLPP Applications Development

Unfunded

Funded

= Field Campaign

NRA NRA NRA NRA NRA NRA

CLPP MISSION

OPER CLPM MISSION

Cold Land Processes Pathfinder (CLPP) Mission

Cold Land Processes Measurement (CLPM) Mission

Increased coordination and collaboration with polar regions and sea ice

communities

CL

PX

III

Cold Land Processes Working Group

GAPP GAPP GAPP GAPP GAPP GAPP

Cold Land Processes Roadmap

Airborne Imaging Ku SAR

CLPP Airborne Simulator• Quantification of high latitude precipitation, fresh water stored in seasonal snowpacks, controls on variability of storage, snowpack feedback effects on weather and climate

CL

PX

VV

ali

da

tio

n

Development of International Partnerships

CLPP Proposal

NRA NRA NRA NRA NRA

March 2-4 2005 24

Terrestrial Snow


Cryosphere Theme

• Two-frequency Ku-band SAR• Ku-Band (13 and 17 GHz)• 100 m Resolution (60 looks)• Swath: 35km• 100 W Peak Transmit Power• Incidence angle: ~30 degrees• Polarization: VV, VH

• K/Ka-band Radiometer• 7/4 km resolution• Swath: 45km (K-band), 40km (Ka-band)• Polarization: H

• Orbit/Launch/Spacecraft• Sun-synchronous, 510km, 5-6 pm ascending• 6-day repeat• Ball 2000 or SA200HP or Equivalent• Peacekeeper L/V

CLPP Baseline Mission Concept

6-Day Repeat Swaths

Latitude 70 60 50 40

Track Separation 140 km 214 km 279 km 335 km

1.95 m pushbroom reflector with offset feeds

Feb 2004 Snow Extent

March 2-4 2005 25

Terrestrial Snow


Cryosphere Theme

CLPP Fills Important Gap in Observation of Processes

Spatial Scale

Te

mp

ora

l S

ca

le

10m 100m 1km 10km 100km 1000km1

10

100

1000

10000

100000

3 Days

1 Day

1 Week

1 Month

1 Hour

1 Year

2 Years3 Years

Te

mp

ora

l S

ca

le (

Ho

urs

)

10 Years

Interannual Variability in Snow Accumulation

(Variation in Synoptic Climate)

Snowmelt Floods

Snow Metamorphism Effects on Microwave and Optical

Radiative Transfer

Intraseasonal Variability in Snow Accumulation

(Variation in Individual Storm Tracks)

30-Year Legacy of Passive Microwave Remote Sensing of Snow

Cold Land Processes Pathfinder Measurements

Snow Melt Effects on Water Balance, Surface Energy Balance and Microwave Radiative Transfer

Enhanced Boundary-layer Stability over Snow

Wind-redistribution of Snow Accumulation on the

Ground

Synoptic Storm Systems

(Snow Precipitation and Accumulation)

Orographic Precipitation Effects on Snow Accumulation

Effects of Snow Cover on Heat and Moisture Exchanges with Advecting Airmasses

March 2-4 2005 26

Terrestrial Snow


Cryosphere Theme

AlgorithmValidation

RadiometerTbH19

TbH37

RadarVV HV Ku

VV HV Ku

Ancillary Data

(Vegetation, Topography)

Active Microwave Algorithm

Passive Microwave

Model-based

Estimation

FUSION

Building Block

Science Investigation

CLPP Swaths Only

SWEWetness Depth

Grain SizeDensity

Roughness*(*TBD)

Level 2 & 3 Products

Near Real Time During Flight

Global (synoptic)

Snow Analyses (Uncoupled

Modeling/Assim)

Building Block

Near Real Time and Post-flight

Snow/LandModeling & Assimilation

(Coupled & Uncoupled)

PreparatoryScience/Application

Investigations

Level 4 Products

Global

SWEWetness Depth

Grain SizeDensity

SnowmeltSnow Temp

FluxesRunoff

Level 3 Gridded Backscatter and Brightness Data

Uncertainty Assessment

Benefit: NPOESS/CMIS Risk Reduction (Snow Cover Depth and SWE EDRs)

Major Science and

Application Investigations

Analysis of Local-Global Snow Water

Storage, Fluxes, and Variability

Exploration of Snow Cover on

Sea Ice

Operational Demonstration

Hydrological Analysis and Forecasting

Preparatory Science Investigations

ModelValidation

Level 1Products

Quantify Ice-Sheet Snow

Accum. & Melt Characteristics

CLPP Investigation Pathway

March 2-4 2005 27

Terrestrial Snow


Cryosphere Theme

Terrestrial SnowTwo Perspectives:

NOAA Weather and Water OperationsNASA Earth Science Research

Don Cline

Office of Climate, Water and Weather Services, National Weather Service, NOAA

National Operational Hydrologic Remote Sensing Center

Cryosphere Theme

March 2-4 2005 28

Terrestrial Snow


Cryosphere Theme

• Snow is a significant storage component of the fresh water cycle1, affects weather and climate2, is a critical fresh water resource in many mountainous regions and surrounding lowlands3, and is frequently responsible for loss of life and property due to flooding4.

• Snow water storage is highly variable in space and time, but appears to be changing in significant ways, including increasing snow accumulation at different times and locations, in contrast to some climate change hypotheses.

• 1On one day in Feb 2004, NWS model analyses indicated the volume of water stored in snow across the CONUS was 11% of the U.S. total annual renewable fresh water resources (258 km3; 59% of estimated U.S. total annual freshwater withdrawal).

• 2In addition to the well-known ice-albedo feedback, snow cover depresses overlying air temperatures, which decreases atmospheric thickness, and in turn steers cyclonic activity which affects subsequent snowfall. Persistence of these effects depends on mass of snow (water) present.

• 3E.g., in the western U.S between 80-90% of total annual streamflow originates as snow .

• 4Eight of the top 20 floods of the 20th century were related to snowmelt (USGS). Three caused over $1B each in damages (2002 dollars).

Science Drivers

Terrestrial Snow Two Perspectives: NOAA Weather and Water Operations NASA Earth Science Research Don Cline Office of Climate, Water and Weather Services,

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