1. Hindcast Simulations of Hydrodynamics in the Northern Gulf of Mexico Using the FVCOM Model Zizang Yang 1, Eugene Wei 1, Aijun Zhang 2, Richard Patchen 1 and Frank Aikman 1 1 Coast Survey Development Laboratory, NOAA/NOS, Silver Spring, MD 2 Center for Operational Oceanographic Products and Services (CO-OPS), NOAA/NOS, Silver Spring, MD

2. Northern GOM - Maritime navigational safety: water level, velocity and T/S - Support NOS Port OFS development: open boundary conditions - Ecosystem related modelings: HAB, Hypoxia, etc Introduction NGOFS domain NGOFS - NOAA/NOS Northern Gulf of Mexico Nowcast/Forecast System - Scheduled to start operational runs on April 1, 2012!

3. Outline -Numerical Methods -Setup of Hindcast simulations -Results -Model-data comparisons -Summary & Future work

4. Methods -Finite Volume Coastal Ocean Model (FVCOM) Unstructured, 3-D prognostic, hydrostatic -Forcing  Open ocean boundary  Meteorological forcing  River discharge - Model grid  Horizontal resolution: 150 m–11 km  Vertical co-ordinate: 41 sigma levels H < 200 m: evenly spaced H > 200 m: top/bottom 5 layers: constant 5-m spacing middle layers: evenly spaced Nodes: 90,267 Elements: 174,474 Bathymetry

5. Forcing Terms Period 1 (July’ 08-Sept’09) Period 2 (Sept.’ 10-March’ 11) Open ocean boundary (wl, T, S, u, v) (Tidal + nontidal) Tidal: ADCIRC EC2001 tidal database Subtidal: one-way coupling with NOAA/NOS NGOM Tidal: ADCIRC EC2001 tidal database Subtidal: one-way coupling with Navy G-NCOM (Region 1) Surface forcing (U 10, T air, P atm, RH, SW, LW) NARR - 3 hourly - 30-km resolution NAM - 3 hourly - 10-km resolution River discharges USGS river gauge data daily averaged discharge rate, T, S USGS river gauge data - daily averaged discharge rate, T, S Two periods of Hindcast Simulations

6. Coupling with Regional Ocean Models - NOAA/NOS NGOM - 1 st hindcast Period: July’ 08-Sept’ 09 - Bathymetry on open ocean boundary - Non-tidal water level, u, v, and T/S - Navy Global NCOM (region 1) - 2 nd hindcast Period : Sept.’ 08-March’ 11

7. Results -Consistency with coupled NGOM/NCOM results -Data-model comparisons -Data: TABS, NWLON, C-MIST -Time series: water level, (u,v), and T/S TABS - Texas Automated Buoy System NWLON - NOAA/NOS National Water Level Observation Network C-MIST – NOAA/NOS Currents Measurement Interface for the Study of Tides

8. T (deg C) (10-m depth) Consistency with NGOM Results 2008-09-01 T00:00 S (psu) (10-m depth) NGOMNGOFS 2009-04-01 T00:00 NGOMNGOFS 2008-09-01 T00:00 NGOMNGOFS 2009-04-01 T00:00 NGOMNGOFS

9. T (deg C) (10-m depth) Consistency with NCOM Results 2010-11-01 T00:00 NCOMNGOFS NCOMNGOFS 2011-03-01 T00:00 S (psu) (10-m depth) 2010-11-01 T00:002011-03-01 T00:00 NCOMNGOFS NCOMNGOFS

10. 1 st Hindcast – Water Levels & Currents C-1 C-2 Wl-1 Water level Wl-2 Wl-3 Sta: wl-2 Sta: wl-3 Sta: wl-1 b: obs r: ngofs Sta: C-1 Sta: C-2 Speed (m/s) b: obs r: ngofs C-1 C-2 C-1 C-2 Currents Speed (m/s) Dir (deg from N.)

11. T Sta A Sta B Sta C S Sta A: A Sta B Sta C AB C 1 st Hindcast – T/S Blue: observations Red: NGOFS

12. 2 nd Hindcast - Water Level & Currents Sta A Sta B Sta C Sta D C D A B B A Sta A Sta B black: obs red: NGOFS Speed (m/s) Direction (deg from N.) Speed (m/s) Direction (deg from N.)

13. 2 nd Hindcast: Temperature (deg C) C D A B Sta B Sta C Sta D Sta E Sta F EF Sta A black: obs r: NGOFS

14. 2 nd Hindcast: Salinity (psu) C B A D Sta A Sta C Sta B Sta D black: obs red: NGOFS

15. Summary - Two hindcast simulations  1 period: July’ 08-Sept’ 09 coupled with NOAA NGOM  2 period: Sept.’ 10-March’ 11 coupled with Navy NCOM - Successful coupling with basin-scale models - Favorable model-data agreement

16. Future Work -Continue skill assessments TABS, NWLON, C-MIST, CTD Satellite SST -Optimize model parameter setup Questions ?