Transcript Mapping the Mid-Atlantic Cold Pool Evolution and

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
NOAA/NMFS 1979 Survey Bottom Temperatures
Remnant Winter Water
Isolated by spring stratification
Fed by Cold Water from upshelf
Ou & Houghton 1982
The COLD POOL is extensive & elusive
….is always evolving in TIME-SPACE
….from cradle to grave
Advected by downshelf flow
Eroded by cross-shelf exchanges
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
How Do We Define and Forecast COLD POOL?
…with the power of MARACOOS!
Mid Atlantic Regional Association Coastal Ocean Observing System
Design, Testing and Deploy
Observatory (simulated) data
Models
~3 km
Sensor &
Platform
Hyperion
on EO-1
~100
m
Virtual Ocean
Data Assimilation
Data
Analysis
Science Questions & Drivers
Data Synthesis:
Nowcast & Data Impact
1
Opportunistic “slices of the COLD POOL” ..with gliders
MARACOOS
Glider Trajectory
Composite
2003 - present
• repeat cross-shelf
• zig-zag along-shelf
• zig-zag inner-shelf
red /orange/yel
cyan
dark blue
(Schofield et al., 2010).
Gliders operations -virtually independent of weather
…..can be maintained at sea essentially indefinitely
Glider Cost Effectiveness
Ocean Gliders
- a robust tool for monitoring coastal ocean dynamics in the Middle Atlantic region -
Endurance transect time series 2003-2010
55 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!
Historical
Temperature
Transects
2012 Glider Temperature Transects
south of Massachusetts and Rhode Island
June 1-5 2012
T ~ 8.5oC
23-28 May 2007
T ~ 5.0oC
14-19 April 2011
T ~ 4.9oC
April 1-5 2012
T ~ 7.5oC
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