GODAE Final Symposium, 12 – 15 November 2008, Nice, France Global High Resolution Analyses and Forecasts at the Mesoscale H. Hurlburt 1, Y. Drillet 2, G. Brassington 3, M. Benkiran 4, E. Chassignet 5, J. Cummings 6, M. Drevillon 7, H. Etienne 4, O. Le Galloudec 2, E.J. Metzger 1, P. Oke 8, T. Pugh 3, A. Schiller 8, J.F. Shriver 1, O.M. Smedstad 9, B. Tranchant 7, A. Wallcraft 1, G. Warren 10 1 Naval Research Laboratory, Stennis Space Center, MS, USA 2 Mercator-Océan, Ramonville Saint Agne, France 3 Centre for Australian Weather and Climate Research, BoM, Melbourne, Australia 4 CLS, Ramonville Saint Agne, France 5 Florida State University, COAPS, Tallahassee, FL, USA 6 Naval Research Laboratory, Monterey, CA, USA 7 CERFACS, Toulouse, France 8 Center for Australian Weather and Climate Research, CSIRO, Hobart, Australia 9 Planning Systems Inc., Stennis Space Center, MS, USA 10 Bureau of Meteorology, Melbourne, Australia

Sea Surface Height (SSH) Variability From satellite altimetry (CLS) From a 1/12  Mercator Océan simulation without data assimilation (using the NEMO model) (in m 2 )

SSH Variability in the Gulf Stream Region 45  N 40  N 35  N 30  N 45  N 40  N 35  N 30  N 80  W70  W60  W50  W40  W 4 years from 1/12  global HYCOM with climatological forcing and no data assimilation Along altimeter tracks in 4 orbits spanning From Hurlburt and Hogan (2008, DAO) courtesy Gregg Jacobs (NRL).

MODIS Ocean Color vs 10-day Gulf Stream Region Current Speed Forecasts from 3 Mercator-Océan Systems on 23 April 2008 MODIS 1/12  global 1/4  global 1/12  Atlantic All the Mercator Océan systems use the NEMO model and SEEK data assimilation

East Australian Current System on 8 March /10  Operational BLUElink Nowcast1/10  BRAN 2.2 Reanalysis ± 2-day drifter trajectories overlaid on sea level anomalies and ocean currents Both are global with 1/10  resolution in the Australian region (90  E-180  E, 75  S-16  N) and use MOM4 with multivariate EnOI data assimilation

GODAE Final Symposium, 12 – 15 November 2008, Nice, France 1/10  Operational BLUElink Nowcast 15 Feb 2007 – 30 Apr 2007

Eddies in Ocean Model Nowcasts vs SeaWiFS Ocean Color in the Northwestern Arabian Sea and Gulf of Oman on 6 Oct Adapted from Hurlburt et al. (2008; AGU Monograph 177)

Eddies in Ocean Model Nowcasts vs SeaWiFS Ocean Color in the Northwestern Arabian Sea and Gulf of Oman on 6 Oct Adapted from Hurlburt et al. (2008; AGU Monograph 177) Prediction System Resolution at 20  N 1/16  NLOM 8 km 1/32  NLOM 4 km 1/8  NCOM 18 km 1/12  HYCOM 8km 1/32  NLOMn No Assim % of Eddies Present in the Model All eddies Large eddies, Small eddies, Median Eddy Center Position Error, km All eddies Large eddies Small eddies

Eddies in Ocean Model Nowcasts vs SeaWiFS Ocean Color in the Northwestern Arabian Sea and Gulf of Oman on 6 Oct Adapted from Hurlburt et al. (2008; AGU Monograph 177)

(in cm) 24°N 22°N 20°N 18°N 16°N 26°N 24°N 22°N 20°N 18°N 16°N 26°N 56°E58°E60°E62°E 56°E 58°E60°E62°E 56°E 58°E60°E62°E 29 Sept Oct Sept /32  NLOM Nowcast SSH and Currents with Altimeter Tracks Overlaid  Altimeter track data from ERS-2 (red), GFO (black), and JASON-1 (white) were assimilated daily using a 3-day data window and the model as a first guess  Altimeter tracks are overlaid with the most recent seven days as solid lines  Daily MODAS SST analyses are also assimilated  Atmospheric wind and thermal forcing is from FNMOC/NOGAPS Adapted from Hurlburt et al. (2008; AGU Monograph 177)

1/12  Global HYCOM forecasts vs. Verifying Analyses  20 Forecasts included in statistics * Reverts toward climatology at end of atmospheric forecast. Atmospheric analysis forcing operational forcing* persistence World Ocean Gulf StreamNW Arabian Sea and Gulf of Oman Equatorial Pacific Kuroshio Yellow and Bohai Seas north of 30  N Forecast length (days) Median SSH anomaly correlation Partly from Hurlburt et al. (2008; AGU Monograph 177)

Verification of 30-day Forecasts of SSH vs Unassimilated Tide Gauge Data 1/12  HYCOM, with analysis quality forcing 1/12  HYCOM, with operational forcing 1/32  NLOM1/16  NLOM Adapted from Hurlburt et al. (2008; AGU Monograph 177) Open Ocean IslandsCoastal Both A 13-day moving average was applied to filter time scales not resolved by the altimeter data

CC Mercator Océan Atlantic SST Forecast Error vs SST Analysis 1-day RMS Error 7-day RMS Error Length of Forecast (days) RMS Error (  C) persistence forecast

Strong Coastal Upwelling Event off Southern Australia Observed SST Organisations Bonney coast off South Australia is a location of frequent coastal upwelling The upwelling in Feb 2008 was one of the largest events ever recorded 10 Feb 2008 BLUElink SST 10 Feb 2008 MODIS ocean color 30 Mar 08 Australia 15 Jan – 15 Feb mean winds

Organisations South Australia non tidal sea level exceeded 0.6m, 29 th October 2007 Tasmania, Derwent River, non tidal signal ~0.4m, 9 th August 2007 Hobart Mercury, 10 th August 2007 “WILD weather and huge downpours continue to flood three major valleys in Tasmania, triggering car crashes, fires and a dangerous landslide.” Sea Level Anomaly BLUElink Prediction of Coastal Trapped Wave Events around Australia

Organisations Non-tide residual (m) South Australia, Thevenard coastal tide gauge Comparison of OceanMAPs (  ) and non tidal sea level CTG (  ) BLUElink Coastal Trapped Wave Nowcast Accuracy at the Thevenard, Australia Coastal Tide Gauge Thevenard

RMSE (m) Forecast period (days) BLUElink Coastal Trapped Wave Forecast Accuracy around Australia