U.S. GODAE: Global Ocean Prediction with

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U.S. GODAE Global Ocean Prediction with
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
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GODAE The vision

• "A global system of observations, communications,
  modeling and assimilation, that will deliver
  regular, comprehensive information on the state
  of the oceans in a way that will promote and
  engender wide utility and availability of this
  resource for maximum benefit to society."

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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.

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Objectives and Goals

• 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 http//www.hycom.org

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The hybrid coordinate in HYCOM is one that is
isopycnal in the open, stratified ocean, but
smoothly reverts to a terrain-following
coordinate in shallow coastal regions, and to
pressure coordinate in the mixed layer and/or
unstratified seas
1/25 East Asian Seas HYCOM (nested inside 1/6
Pacific HYCOM)
North-south velocity cross-section along 124.5E,
upper 400 m
bluewestward flow
redeastward flow
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Roadmap

• Basin-scale
• FY04 to FY07 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.
• The NOAA/NCEP Pacific configuration will become
  operational in FY08.

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Configuration of the Basin-Scale Prediction
Systems
http//www.hycom.org

• NRL NOAA/NCEP

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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

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Present NRL nowcast/forecast systems

• 1/12º Atlantic near real-time system
• - Running once a week since July 2002
• - Assimilation gridded surface observations
  only
• - 10 day hindcast, 14 day forecast
• 1/12º Global real time system
• - Running since December 2006
• - Assimilation NCODA
• - 5 day hindcast, 5 day forecast
• 1/25º Gulf of Mexico real time system
• - Running since November 2006
• - Assimilation NCODA
• - 5 day hindcast, 7 day forecast

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Present NCEP nowcast/forecast system

• 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
• TidesM2, 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 using SLA from JASON GFO (not
  activated)
• T,S from ARGOS, XBT, CTD (not activated)

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Global HYCOM configuration

• 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 79S to 47N, then Arctic dipole patch
• 32 s2 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

216,000 CPU hrs/model year on 784 IBM Power 4
CPUs 7.2 TB/model year for daily 3-D output
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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 s2
with climatological wind and thermal forcing
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Mean Sea Surface Evaluation
1992-2002 Mean dynamic ocean topography (0.5)
Mean ocean dynamic topography data has been
obtained from Nikolai Maximenko (IPRC) and Peter
Niiler (SIO)
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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
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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 )
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SST Response in 1/12 Global HYCOM to Hurricanes
Katrina and Rita
NDBC buoy 42040 south of Mobile Bay
NDBC buoy 42036 SE of Pensacola
RMS .67C R .89
RMS .56C R .95
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.
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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)

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Data Assimilation via NCODA (Cummings et al.)

Ocean obs
Sequential Incremental Update Cycle
Analysis-Forecast-Analysis
Ocean data QC
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
Ocean data Analysis 3D MVOI Cooper-Haines
Increments
Ocean model HYCOM
Forecast Fields Prediction Errors
First Guess
MVOI - simultaneous analysis 5 ocean variables
temperature, salinity, pressure, velocity (u,v)
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with assimilation (GLBa0.08-60.4)
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without assimilation (GLBa0.08-05.8)
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Overall increase in variability - largest changes
occur in the western boundary currents
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Eddy Kinetic Energy Comparison
Surface EKE in the Gulf Stream



Observations from Fratantoni (2001) Based on
1990-99 surface drifters
NCOM - 2004
HYCOM - 2004
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Eddy Kinetic Energy Comparison
EKE at 700 m in the Gulf Stream



Observations from Schmitz (1996)
HYCOM - 2004
NCOM - 2004
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Mixed Layer Depth Comparison
2004 MLD difference HYCOM minus unassimilated
MEDS profiles



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



4232 Profiles Mean error -2.1 m RMSE 41.6 m
MLD negative temperature difference of 0.5C
between the surface and depth data averaged in
0.5 bins
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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
os) 1, 20, 40, 60, 80, 100, 120, 140, 180, 300,
500 m. Set 2 (denoted by xs) 1, 25, 50, 75,
100, 125, 150, 200, 250, 300, 500 m.
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Temperature Structure Comparison




2004 subsurface temp at 140W, 2N Buoy / HYCOM
/ nonassim HYCOM
Temperature difference Buoy - HYCOM / Buoy -
nonassim HYCOM
Significant impact of temperature profile
assimilation via NCODA
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Temperature Structure Comparison
HYCOM vs. non-assim HYCOM Mean error 47
TAO/PIRATA buoys 2004
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Forecast verification statistics from .08?
global HYCOM
1.0
0.9
0.8
0.7
World Ocean
NW Arabian Sea and Gulf of Oman
Gulf Stream
Median SSH anomaly correlation
1.0
0.9
0.8
0.7
Equatorial Pacific
Kuroshio
Gulf of Mexico
0.6
0
Forecast length (days)
4 Forecasts included in statistics
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Product evaluation

• Assessment of the outputs by comparison to
  independent observations
• Comparison with other GODAE products (i.e. MERSEA
  collaboration)
• Strong involvement of coastal ocean modeling
  groups to use and evaluate boundary conditions
  provided by the global and basin HYCOM real time
  prediction system outputs

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Ivan Simulation (G. Halliwell, U. of Miami)

• Run within the 1/25 GOM Domain
• Initial and Boundary Conditions from NCODA
• GISS Vertical Mixing
• Atmospheric Forcing
• Very important - must resolve the inner core of
  the storm
• Start with the 0.5-degree NOGAPS forcing
• Problems
• Eye and eyewall poorly resolved
• Maximum winds underestimated by 30-40
• Blend NOGAPS wind field with HWIND gridded vector
  wind fields from NOAA/HRD
• Produce wind speed and wind stress forcing fields
  that resolve the inner core structure

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West Florida Shelf Modeling
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.

• Barth et al. (USF)

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• Barth et al. (USF)

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Regional model for South Florida
seasSoFLA-HYCOM(South Florida Hybrid Coordinate
Ocean Model)
Surface temperature and velocity
Nested boundaries
Kourafalou et al. (U. of Miami)
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Nested South Atlantic Bight Finite Element Model
UNC-SAB modeling system sequence that nests the
regional-scale QUODDY implementation (middle)
within the 1/12 near real-time HYCOM-GODAE model
(left). The limited-area QUODDY implementation
(right) includes the estuary and tidal inlets
along the Georgia/South Carolina coast and
extends to the shelf-break.
Blanton et al. (UNC)
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Boundary conditions for the CARIACO basin
(Alvera-Azcarate and Weisberg)
Atlantic HYCOM
Figures show the 2004 temperature average (space
and time) for HYCOM and climatology (based on
Levitus data) at northern model boundary



Global NCODA HYCOM
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US West Coast HYCOM with Biology Nested in 1/12
Global HYCOM Basin
Kindle et al. (NRL)
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COMPARISONS (Global Models)
(Kindle and deRada)
r .8
r .76
Gridded Altimeter SSH-June 16 AVISO Product
Gridded Altimeter SSH-June 16 NAVO Product
Global NCOM SSH Anomaly June 16 2004
Global HYCOM SSH Anomaly June 16 2004
Global NCOM SSH Anomaly June 16 2004
Global HYCOM SSH Anomaly June 16 2004
Global HYCOM with SeaWIFS Chlorophyll June 16
2004
Global NCOM with SeaWIFS Chlorophyll June 16 2004
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COMPARISONS (Global Models)
(Kindle and deRada)
Global HYCOM with SeaWIFS Chlorophyll June 16
2004
Global NCOM with SeaWIFS Chlorophyll June 16 2004
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Model Evaluation Tide Gauges
Regional NCOM Forced by NCOM and HYCOM
Global NCOM and HYCOM
Global HYCOM and NCOM nest represent Coastal
Kelvin Wave Pulses More Accurately
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Model Evaluation Tide Gauges
Regional NCOM Forced by NCOM and HYCOM
Global NCOM and HYCOM
Global HYCOM and NCOM nest represent Coastal
Kelvin Wave Pulses More Accurately
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Wetting and Drying in HYCOM
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Wetting and Drying in HYCOM
Baraille et al. (SHOM)

0 meter layer thickness