MARCOOS/ESPreSSO ROMSRU Coastal Ocean Modeling and Prediction group
John Wilkin, Gordon Zhang, Julia Levin, Naomi Fleming, Javier Zavala-Garay, Hernan Arango
5 km resolution for assimilation
1 km resolution for forecast
NCEP NAM 3-hour meteorology
1-day average USGS gauge river flow
Open boundaries: ROMS MAB-GoM nested within GODAE-HyCOM operational N. Atlantic (He/NCSU)
> OPeNDAP data portal
> Assimilation experiments in 2006 (4DVar)
> Glider observation analysis (Representers)
Assimilation and observing system design experiments in 2006 (LaTTE and SW06)
> LaTTE subdomain
RU CODAR (with tides)
All glider CTD
All moored T/S
> SW06/MARCOOS/ESPreSSO
Now: Climatology (Hydrobase); AVISO altimetry in Slope Sea; SST (AVHRR/MODIS/GOES
blended from PFEL CoastWatch)
Soon: regional climatology; glider; VOS/XBT; Argo
Future: coastal along-track altimetry; in situ and satellite optics and ocean color
> Glider observing system design
use representers to analyse information content of MARCOOS glider tracks
X_afterDAforecast_skill = 1
X_beforeDA
2X = MSE, MB , 2 (1 CC)m oS S
Forecast skill improvement with assimilation of CODAR60-day ensemble of all analyses/forecasts
u “along-shelf” component
forecast windowanalysis forecast windowanalysis
after assimilating CODAR data
(Oke, et al, 2002)
2 2MSE = MB SDE 2 (1 CC)m oS S MB ( )m o SDE m oS S
0
1
0
1no assimilation of CODAR data
X_afterDAforecast_skill = 1
X_beforeDA
2X = MSE, MB , 2 (1 CC)m oS S
Forecast skill improvement with assimilation of CODAR60-day ensemble of all analyses/forecasts
v “across-shelf” component
forecast windowanalysis forecast windowanalysis
after assimilating CODAR data
(Oke, et al, 2002)
2 2MSE = MB SDE 2 (1 CC)m oS S MB ( )m o SDE m oS S
0
1
0
1no assimilation of CODAR data
The “Representer” (Bennett) is a measure of the covariance/correlation between ocean state variables and a pattern of observations
Method: integrate the adjoint model backwards forced at observational locations, then the tangent linear model forward to carry “information” to analysis/forecast times
Cost function:
Covariance between J and temperature,
, reflects the
influence of glider observation
2
1
2 2
2 1
1( ) ( )
( )
t
t L
J T T S S dLdtL t t
cov( , ( , , , ))J T x y z t
At time = finish of glider mission
At time = 5 days after finish of glider mission
Cost function:
Covariance between J and temperature,
, reflects the
influence of glider observation
2
1
2 2
2 1
1( ) ( )
( )
t
t L
J T T S S dLdtL t t
cov( , ( , , , ))J T x y z t