new york harbor observing and prediction system
DESCRIPTION
ASSIMILATION OF HIGH-FREQUENCY RADAR SURFACE CURRENTS INTO A COASTAL OCEAN MODEL OF THE MIDDLE ATLANTIC BIGHT Alan F. Blumberg George Meade Bond Professor Director Davidson Laboratory Stevens Institute of Technology Liang Kuang and Nickitas Georgas I EEE-MTS 12 Ocean Meeting - PowerPoint PPT PresentationTRANSCRIPT
ASSIMILATION OF HIGH-FREQUENCY RADAR SURFACE CURRENTS INTO A COASTAL OCEAN MODEL OF THE MIDDLE ATLANTIC BIGHT
Alan F. Blumberg
George Meade Bond Professor Director Davidson Laboratory Stevens Institute of Technology
Liang Kuang and Nickitas Georgas
IEEE-MTS 12 Ocean Meeting October 17, 2012
New York Harbor Observing and Prediction SystemIntegrated system of observing sensors and forecast modelsTO OBSERVE TO PREDICTTO COMMUNICATE Weather Currents Water Level Salinity Temperature Waves
How?
Observe
Ground-Truth ServeAutomatically
Forecast
A fully automated system of systemsNew York Harbor Observing and Prediction System
0.5 hrs + 1.5 hrs + 2.0 hrs
C:\Documents and Settings\hroarty\My Documents\COOL\01 CODAR\MARCOOS\Renewal
HF radar System
6
SLDMB Drifter
7
Methodology—Data Assimilation
• Data Assimilation- Nudging Scheme
0( ) ( )u physics u ut
2 0
2( )
( , )1 * * *dNUDGE d
r t t ztR z
i ja
e e et
8
Non-tidal mean surface currents: HF radar vs. NYHOPS
Before After
From Jun 9th, 2011 to Jul 21st, 2011. Scale is in 10cm/s.
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Tidal currents(M2 ellipses) after DA
Before After
From Jun 9th, 2011 to Jul 21st, 2011. Scale is in 10cm/s.
10
uv
RMSE between NYHOPS Hindcast, Drifter currents before and after data assimilation (cm/s)
U U_DA U_diff V V_DA V_diff
1 12.1 11.8 0.3 8.6 8.5 0.1
3 11.1 10.1 1.0 13.7 12.9 0.8
4A 15.5 14.7 0.8 14.3 13.7 0.6
4B 17.5 15.6 1.9 16.9 16.0 0.9
4C 17.2 16.6 0.6 16.8 14.9 1.9
average14.7 13.6 1.1 14.1 13.0 1.1
Positive means improvement
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43 (3X) Reseeding particle-tracking simulations
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RMSE of NYHOPS Forecast, Drifter currents before and after data assimilation (cm/s)
U U_DA U_diff V V_DA V_diff
1 17.5 17.3 0.2 11.2 11.0 0.2
3 17.3 16.1 1.2 13.5 12.4 1.1
4A 19.8 19.1 0.7 16.3 15.4 0.9
4B 22.4 20.6 1.8 22.3 20.3 2.0
4C 27.6 25.9 1.7 22.4 21.4 1.0
Average21.0 20.0 1.0 17.1 16.3 0.8
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43 (3X) Reseeding particle-tracking simulations
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Conclusions• NYHOPS established as an urban ocean forecast system –
large following with multiple constituencies• Using currents derived from drifters for validation:
Average RMS errors of hindcast and 1 day forecast shows 8% improvementsParticle-tracking simulations showed improvements of 7% (hindcast) and 10% ( 1 day forecast) based on separation distances
• The future work - assimilation using more advanced schemes, such as Kalman Filter/LRTKF, 3D and 4D var