Demonstrations of GODAE Impact - Boundary Conditions for a Regional Model and Web Hit Statistics Presented by Harley Hurlburt Naval Research Laboratory Stennis Space Center, MS USA International GODAE Steering Team Meeting St. Johns, Newfoundland, Canada 7-9 August 2007 Part of HYCOM/GODAE project sponsored by the National Ocean Partnership Program

User Interest in Real-time Global Ocean Products NRL Oceanography Division Web Site Hit Statistics during 2005 Top 25 Countries and # Hits Includes the following real-time global Ocean products and other results Altimeter data MODAS SSH & SST analyses Ocean prediction systems 1/16  and 1/32  global NLOM 1/8  global NCOM 1/12  Atlantic HYCOM Total # hits36,452,092 Avg hits/day99,869 # hits used in country breakdown36,342,270 # countries with  1000 hits 70 # countries with  100 hits 127 Total number of countries181 United States27,468,102 Japan7,190,216 Taiwan152,085 China150,733 Russia109,211 Germany103,376 Great Britain98,845 Greece88,603 Spain72,452 Canada66,011 France62,260 Mexico60,198 Philippines56,034 Vietnam53,749 South Korea53,536 Italy42,297 Australia41,128 Singapore40,215 New Zealand37,724 Sweden36,014 India27,820 Denmark26,664 Peru25,642 Netherlands24,191 Norway22,805

WFS ROMS SST and surface velocity is shown inside the dashed line and outside of this area is the North Atlantic HYCOM. Warm water is detached from the Loop Current and transported northward as mesoscale eddies and filaments. From A. Barth, A. Alvera-Azcárate, R. He, R. H. Weisberg University of South Florida Consistency of North Atlantic HYCOM and West Florida Shelf (WFS) ROMS

West Florida Shelf ROMS Nested in HYCOM  Black line shows the boundary of the model domain  Domain is composed by: Broad shelf Broad shelf Deep ocean part Deep ocean part  Both regions are separated by a steep shelf break  The Loop Current is the dominant large-scale feature A. Barth (USF)

Data assimilation: Observations  HF-Radar radial surface currents maps  detided  2-day averaged, but still “noisy”  error estimate provided by instrument Radial velocities measured from the Redington and Venice sites on December 9, Positive values represent current towards the antenna. A. Barth (USF)

RMS error relative to the HF Radar currents RedingtonVenice The RMS time series for the model run without assimilation (free model), the model forecast (before assimilation of CODAR data) and the model analysis (after assimilation) are shown. A. Barth (USF)

Comparison with independent observations  Several ADCP sites on WFS shelf  Error reduction at the surface is expected, but  how does the error behave at depth? A. Barth (USF)

ADCP observations from C10  Free model already very close to observations.  Time averaged RMS shows however that error is reduced. A. Barth (USF)

Sensitivity to Boundary Conditions  Lowest RMS error on the shelf in all simulations  With GOM NCODA HYCOM boundary improvements in C19 and C17 but degradation in C16  Nested model bathymetry needs to be adapted to the outer model bathymetry (which is different in both HYCOM simulations) and involves certain parameters which can be optimized  A more clear-cut comparison may be obtained GoM NCODA HYCOMAtlantic HYCOM A. Barth (USF)