U.S. GODAE: Global Ocean Prediction with Community Effort: Community Effort: NRL, U. of Miami, FSU, NASA-GISS, NOAA/NCEP, NOAA/AOML, NOAA/PMEL, PSI, FNMOC, NAVOCEANO, SHOM, LEGI, OPeNDAP, UNC, Rutgers, USF, Fugro-GEOS, Orbimage, Shell, ExxonMobil

Objectives and Goals A broad partnership of institutions that collaborate in developing and demonstrating the performance and application of eddy- resolving, real-time global and basin-scale ocean prediction systems using HYCOM. To be transitioned for operational use by the U.S. Navy at NAVOCEANO and by NOAA at NCEP.

Strong participation of the coastal ocean modeling community in using and evaluating boundary conditions from the global and basin- scale ocean modeling prediction systems Efficient data distribution (100 Terrabytes Storage Area Network) The data are available to the community at large within 24 hours via Live Access Server (LAS), ftp, and OPeNDAP at Objectives and Goals

Roadmap Basin-scale –FY04 to FY08: Evaluation of data assimilation schemes [MVOI(NCODA), EnOI, SEEK and ROIF]. Improvements to the present near real time NOAA/NCEP North Atlantic configuration. Overlap in FY07 of the near real time NRL North Atlantic configuration and of the global configuration for assessment of the global system in the Atlantic. –Development of a NOAA/NCEP Pacific configuration (to become operational in FY08).

Configuration of the Basin-Scale Prediction Systems NRL NOAA/NCEP

Roadmap Global configuration –Development has been taking place since FY04. –Transition to NAVOCEANO (1/12º) with MvOI (NCODA) in FY07. –Operational testing in year FY08. –Increase to 1/25° resolution globally (~3-4 km mid-latitude) by the end of the decade

1/12º Atlantic near real-time system - Running once a week since July Assimilation: gridded surface observations only - 10 day hindcast, 14 day forecast 1/12º Global real time system - Running since December Assimilation: NCODA - 5 day hindcast, 5 day forecast 1/25º Gulf of Mexico real time system - Running since November Assimilation: NCODA - 5 day hindcast, 7 day forecast Present NRL nowcast/forecast systems

Atlantic real-time system Orthogonal grid (1200 x 1684 points) 25 vertical coordinates (18 isopycnal, 7 z-level) Forcing fields from 3-hour NCEP (GDAS/GFS) model Tides: M2, S2, N2, K1, P1, O1, K2, Q1 tidal modes Rivers from daily USGS data and RIVDIS climatology Data Assimilation –SST: from GOES AVHRR and in-situ –SSH, T, S: SLA from JASON GFO; T, S from ARGO, XBT, CTD Present NCEP nowcast/forecast system

Horizontal grid: 1/12° equatorial resolution – 4500 x 3298 grid points, ~6.5 km spacing on average, ~3.5 km at pole, 5 m minimum depth Mercator 79°S to 47°N, then Arctic dipole patch 32 σ 2 * vertical coordinate surfaces: GISS or KPP mixed layer model Thermodynamic sea-ice model Surface forcing: wind stress, wind speed, thermal forcing, precipitation, weak relaxation to climatological SSS Monthly river runoff (986 rivers) Initialized from January climatology (GDEM3) T and S Global HYCOM configuration 216,000 CPU hrs/model year on 784 IBM Power 4+ CPUs 7.2 TB/model year for daily 3-D output

A.Large scale circulation features Determine correct placement of large scale features B.Sea Surface Height (SSH) variability / Eddy Kinetic Energy (EKE) Determine if the system has a realistic level and distribution of energy at depths C.Mixed layer depth / sonic layer depth / deep sound channel Compare simulated vs. observed for non-assimilated buoys D.Vertical profiles of T&S Quantitative comparison of simulated vs. observed for non- assimilated buoys E.Sea surface temperature Evaluate whether the models are producing acceptable nowcasts and forecasts of sea surface temperature F.Coastal sea level Assess the model’s ability to represent observed sea surface heights FY07 Validation Tasks

Free Running Global HYCOM (Metzger et al.) 1992 – 2005 SSH variability based on T/P, ERS-1, and ERS-2 altimeters (Courtesy CLS) SSH variability from 1/12° global HYCOM σ 2 * with climatological wind and thermal forcing

Mean Sea Surface Evaluation Mean dynamic ocean topography (0.5°) Mean ocean dynamic topography data has been obtained from Nikolai Maximenko (IPRC) and Peter Niiler (SIO)

Mean Sea Surface Evaluation 1/12° global HYCOM – Exp year model mean using climatological ECMWF wind and thermal forcing Std dev (HYCOM - Maximenko-Niiler) = 9.3 cm and the bias = 7.1 cm

Mean Sea Surface Evaluation 2004 Mean sea level from 1/12° global HYCOM/NCODA From the 1/12° global HYCOM/NCODA hindcast simulation Mean shifted by 8.7 cm; standard deviation of difference = 9.6 cm

1/12  Global HYCOM Monthly Mean Mixed Layer Depth Evaluation (Kara et al.) HYCOM MLD – MLD based on the GDEM3 climatology Annual Mean Bias in m RMS difference in m HYCOM was forced by an ECMWF ERA15 Climatology (with 6-hrly submonthly fluctuations added )

SST Response in 1/12° Global HYCOM to Hurricanes Katrina and Rita HYCOM reproduces the deterministic SST response to the wind forcing. Implies realistic upwelling and mixing of subsurface waters as well as realistic atmospheric wind and heat flux forcing. NDBC buoy south of Mobile Bay RMS =.67°C R =.89 NDBC buoy SE of Pensacola RMS =.56°C R =.95

1/12° HYCOM/NCODA/PIPS (Smedstad et al.) Progress: 1/12° global HYCOM/NCODA running in real- time in the NAVOCEANO operational queues; validation testing has begun. Issues: – Complete coupling of HYCOM/PIPS via ESMF (NRL) – Get NCODA working in curvilinear part of grid (NRL) – Need OcnQC running operationally (NAVOCEANO)

29 June 2006 Sequential Incremental Update Cycle Analysis-Forecast-Analysis MVOI - simultaneous analysis 5 ocean variables temperature, salinity, pressure, velocity (u,v) Ocean model HYCOM Ocean data QC Ocean data Analysis 3D MVOI & Cooper-Haines Ocean obs SST: GAC/LAC MCSST, GOES, Ship, Buoy Profile: XBT, CTD, T & S profiling Floats (ARGO), Fixed Buoy, Drifting Buoy Altimeter SSHA SSM/I Sea Ice Innovations Increments Forecast Fields Prediction Errors First Guess Data Assimilation via NCODA (Cummings et al.)

with assimilation (GLBa )

without assimilation (GLBa )

Overall increase in variability - largest changes occur in the western boundary currents

Eddy Kinetic Energy Comparison Surface EKE in the Gulf Stream 3000 cm 2 /s NCOM Observations from Fratantoni (2001) – Based on surface drifters HYCOM

Eddy Kinetic Energy Comparison EKE at ~700 m in the Gulf Stream Observations from Schmitz (1996) HYCOM NCOM

Mixed Layer Depth Comparison 2004 MLD difference: HYCOM minus unassimilated MEDS profiles MLD = negative temperature difference of 0.5°C between the surface and depth; data averaged in 0.5° bins Mean error: -3.0 m RMSE: 43.7 m

Mixed Layer Depth Comparison 2004 MLD difference: HYCOM minus unassimilated MEDS profiles MLD = negative temperature difference of 0.5°C between the surface and depth; data averaged in 0.5° bins 4232 Profiles Mean error: -2.1 m RMSE: 41.6 m

Temperature Structure Comparison Locations of TAO and PIRATA buoys used in this evaluation Buoys are divided into two sets based on the vertical sampling and continuity of the time series over calendar year 2004 Set 1 (denoted by o’s): 1, 20, 40, 60, 80, 100, 120, 140, 180, 300, 500 m. Set 2 (denoted by x’s): 1, 25, 50, 75, 100, 125, 150, 200, 250, 300, 500 m.

Temperature Structure Comparison 2004 subsurface temp at 140°W, 2°N Buoy / HYCOM / nonassim HYCOM Temperature difference Buoy - HYCOM / Buoy - nonassim HYCOM Significant impact of temperature profile assimilation via NCODA

Set 2 Temperature Structure Comparison HYCOM vs. non-assim HYCOM – Mean error 47 TAO/PIRATA buoys 2004 Set 1

24 April th HYCOM Consortium Meeting 2004 subsurface temp at 140°W, 2°NTemperature difference Vertical Temperature Structure Buoy V2.5 V3.0 HYCOM/NCODA - Buoy NCOM - Buoy

Basin-wide mean error: 0°C, RMSE:.2°C Mean error – HYCOM/NCODA vs. MODAS white area = ±.25°C Over 2004 from the V3.0 hindcast simulation Sea Surface Temperature

Over 2004 from the V3.0 hindcast simulation Basin-wide skill score:.90 Skill score – HYCOM/NCODA vs. MODAS Sea Surface Temperature

Over 2004 from the V3.0 hindcast simulation and operational V2.5 V3.0V2.5 ME-.1°C.2°C RMSE.9°C2.2°C R SS Unassimilated MEDS SST vs. HYCOM vs. NCOM Sea Surface Temperature

World Ocean Gulf Stream NW Arabian Sea and Gulf of Oman Equatorial Pacific Kuroshio Gulf of Mexico Median SSH anomaly correlation Forecast length (days) Forecast verification statistics from.08  global HYCOM 4 Forecasts included in statistics

HYCOM RMS errors for M 2 tide vs satellite altimetry.72  resolution.08  resolution Adding tidal capability to global HYCOM  Collaboration with tide model expert, Brian Arbic, U. Texas  For use in.04  global HYCOM with R&D starting in FY09 with state-of-the-art scientific foundation and accuracy RMS error = 9.9 cm RMS error = 6.7 cm Average RMS error over all 102 pelagic tide guages = 12.3 cm HYCOM with 8-component tide vs tide guage.72  HYCOM tide model tide guage Example with typical error: 89.6% of variance explained

Wetting and Drying in HYCOM Mont St Michel

Wetting and Drying in HYCOM 0 meter layerthickness Baraille et al. (SHOM)