Mapping the Mid-Atlantic Cold Pool Evolution and Variability with

Mapping the Mid-Atlantic Cold Pool Evolution and Variability with

Ocean Gliders and Numerical Models 

W. Brown, W. Boicourt, C. Flagg, A. Gangopadhyay,O. Schofield, S. Glenn, and J. Kohut

Cold Pool Context MAB Glider Measurements Cold Pool Glider Measurements

MTS OCEANS’12 Presentation 17 October 2012

The Mid Atlantic Bight (MAB) COLD POOL

Ou & Houghton 1982NOAA/NMFS 1979 Survey Bottom Temperatures

Remnant Winter WaterIsolated by spring stratificationFed by Cold Water from upshelf

The COLD POOL is extensive & elusive….is always evolving in TIME-SPACE

….from cradle to grave

Eroded by cross-shelf exchanges Advected by downshelf flow Destroyed by autumn storms

Modeling suggests & Observations show an INFLOW

Total temperature transport of water with T< 10oC - Cold Pool water - (in 105m3-oC) normal to the 1979 Nantucket Shoals Flux Experiment (NSFE) mooring array. Positive is toward the MAB. (adapted from Ramp et al., 1988)

2010 MODEL SIMULATIONS

“…illustrate the idea, …but have a ways to go”

The Conceptual Bottom-Trapped MAB COLD POOL

1

Observatory (simulated) data

Virtual Ocean

Design, Testing and Deploy

Models

Data Assimilation

DataAnalysis

Science Questions & Drivers

~100 m

~3 kmSensor &Platform

Data Synthesis: Nowcast & Data Impact

Hyperionon EO-1

How Do We Define and Forecast COLD POOL? …with the power of MARACOOS!

Mid Atlantic Regional Association Coastal Ocean Observing System

Opportunistic “slices of the COLD POOL” ..with gliders

MARACOOS Glider Trajectory

Composite

2003 - present

•repeat cross-shelf red /orange/yel •zig-zag along-shelf cyan •zig-zag inner-shelf dark blue

(Schofield et al., 2010).

Gliders operations -virtually independent of weather …..can be maintained at sea essentially indefinitely

Glider Cost EffectivenessOcean Gliders

- a robust tool for monitoring coastal ocean dynamics in the Middle Atlantic region -

Endurance transect time series 2003-201055 glider surveys covering over 18,000 kilometers of the NJ shelf in 826 days.

Cost estimate basis:•a full-time dedicated glider technician for glider prep and monitoring •coastal vessels for glider deployment and recovery•expenses for batteries-Iridium-insurance-nominal maintenance-repair

$6 per vertical profile $47 per kilometer traversed

Cost ~ 1/4 to 1/10 of a typical coastal ocean boat/ship survey.

OCEAN GLIDERs can measure the COLD POOL …. hidden from a satellite’s eye

2-8 August 2011

southeast of NJ

Composite Seasonal Picture

11 Sep-14 Oct 2008 2008 Cold Pool loses distinctiveness

NE CP Temp ~ 9.5oC

23 May-13 Jun 2007 2007 Cold Pool established

NE CP Temp ~ 5.0oC

14 Apr-09 May2011 2011 Cold Pool established off NJ

NE ww Temp ~ 4.9oC

19 Mar-12 Apr 2010 2010 winter waters

NE ww Temp ~ 4.5oC

Eastern MAB 2012 - Warmest Year in many!

2012 Glider Temperature Transects south of Massachusetts and Rhode Island

April 1-5 2012

June 1-5 2012

23-28 May 2007

14-19 April 2011

T ~ 5.0oC

T ~ 4.9oC

T ~ 8.5oC

T ~ 7.5oC

HistoricalTemperature

Transects

A Plan for Sustained Measurements with Data Assimilation Modeling

Summary

• MAB COLD POOL a challenging observational/modeling objective

• Ocean Gliders are a cost-effective observational technology for measuring the Cold Pool

• Data-assmilation modeling:… an essential integrator of information (inc. glider)… Cold Pool forecasting tool