# Presentation: 888172

## 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

## 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."

## 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 http://www.hycom.org

- 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

**Objectives and Goals**

## 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

**(nested inside 1/6****°**** Pacific HYCOM)**

**North-south velocity cross-section along 124.5°E, upper 400 m**

**red=eastward flow**

**blue=westward flow**

- 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

**Notes:**
Note the sharp feature in the bottom topography near 25°N.  It is shallow, rising to about 125m, and is only a few grid points wide. It could not be accurately represented by sigma coordinates. However, in the top panel it is associated with a sharp density front (sharp rise in isopycnal depth above the lip topography) and the location of the Kuroshio.

This provides a good example of all three vertical coordinates within HYCOM: z-levels in the mixed layer, isopycnals in the deeper ocean but also over the shelf, and sigma coordinates in the shallow water. Note the adaptive vertical coordinate that changes from isopycnal in shallow water in October to sigma and z levels in April when the water is less stratified.

## Slide 6

## 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.

## Configuration of the Basin-Scale Prediction Systems

-            NRL                         NOAA/NCEP

**http://www.hycom.org**

## 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 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

- 		- 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

**Present NRL**
**nowcast/forecast systems**

**Notes:**
Present near real-time system, Atlantic Ocean, run since July of 2002. Only gridded full field surface observations are assimilated in this system. 
Running on kraken on 28 nodes, 224 cpus. Results on the hycom consortium web page and there is a LAS server where the data can be obtained.

## 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: using SLA from JASON GFO (not activated) 
T,S: from ARGOS, XBT, CTD (not activated) 

- 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: using SLA from JASON GFO (not activated)
- T,S: from ARGOS, XBT, CTD (not activated)

**Present NCEP **
**nowcast/forecast system**

**Notes:**
Present near real-time system, Atlantic Ocean, run since July of 2002. Only gridded full field surface observations are assimilated in this system. 
Running on kraken on 28 nodes, 224 cpus. Results on the hycom consortium web page and there is a LAS server where the data can be obtained.

## 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 σ2* 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

-  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 σ2* 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

**Notes:**
Mainly climatological simulation so far. A couple of interannual forced cases.

## Free Running Global HYCOM (Metzger et al.)

**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 σ2* with
- climatological wind and
- thermal forcing

## Mean Sea Surface Evaluation

**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)

**Notes:**
1992-2002 Mean Dynamic Ocean Topography calculated using satellite altimeter data, near-surface drifters, NCEP wind and GRACE output.

Improved global mean sea level is obtained by combining two datasets: large-scale mean sea level based on measurements of twin-satellite mission GRACE and mesoscale sea level tilt derived from the momentum balance as seen in drifter, satellite altimeter and wind data. Hybrid product reveals complex structures of main currents even after averaging over 10 years and shows their places in the large-scale near-surface circulation. 

Areal mean of 1.1 cm (over ±70°) subtracted here.

## Mean Sea Surface Evaluation

**Mean Sea Surf****ace**** 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

**Notes:**
Areal mean of 8.7 cm (over ±70°) subtracted here.

## 1/12 Global HYCOM Monthly Mean Mixed 

**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 

**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 42040
- south of Mobile Bay

- RMS = .67°C
- R = .89

- NDBC buoy 42036
- 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)

## Data Assimilation  via NCODA

**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.)**

- 29 June 2006

**Notes:**
NCODA proof of concept working in global HYCOM. Multi variate optimal interpolation scheme, that can assimilate surface observations from satellite, altimetry, mcsst, and also profile data like xbts, palace floats. The forecast fields from HYCOM are used as a first guess for the NCODA analysis. These increments are then nudged into HYCOM.

 Observations feed into NCODA that performs a QC check.
 NCODA performs an ocean data analysis (MVOI of 5 ocean variables)
 Provides increments to the model initial state (nudged in)
 Model runs forward in time
 Model forecast is used as a 1st guess for the next ocean data analysis

What gets assimilated? SSHA from altimeters, SST from various sources, profile data

## with assimilation (GLBa0.08-60.4)

## without assimilation (GLBa0.08-05.8)

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

## Eddy Kinetic Energy Comparison

**Eddy Kinetic Energy Comparison**

- Surface EKE in the Gulf Stream

- NCOM - 2004

- Observations from
- Fratantoni (2001) –
- Based on 1990-99
- surface drifters

- HYCOM - 2004

**Notes:**
Observations based on 15m drougued drifters over the period 1990-1999.

## Eddy Kinetic Energy Comparison

**Eddy Kinetic Energy Comparison**

- EKE at ~700 m in the Gulf Stream

- Observations from
- Schmitz (1996)

- HYCOM - 2004

- NCOM - 2004

## Mixed Layer Depth Comparison

**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

**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

**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

## Temperature Structure Comparison

**Temperature Structure Comparison**

- HYCOM vs. non-assim HYCOM – Mean error
- 47 TAO/PIRATA buoys 2004

## Forecast verification statistics 

**World**
**Ocean**

**Gulf Stream**

**NW Arabian Sea and Gulf of Oman**

**Equatorial**
**Pacific**

**Kuroshio**

**Gulf of Mexico**

- 1.0

- 0.9

- 0.8

- 0.7

- 1.0

- 0.9

- 0.8

- 0.7

- 0.6

**Median SSH anomaly correlation**

- 0

**Forecast length (days)**

**Forecast verification statistics **
**from .08******** global HYCOM**

- 4 Forecasts included in statistics

## 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

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

**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

## Slide 33

## West Florida Shelf Modeling

**Barth et al. (USF****)**

**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)**

## Regional model for South Florida seasSoFLA-HYCOM(South Florida Hybrid Coordinate Ocean Model)

- Nested boundaries

**Surface temperature and velocity **

**Kourafalou et al. (U. of Miami)**

## Nested South Atlantic Bight Finite Element Model

**Blanton et al. (UNC)**

**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.**

## Boundary conditions for the CARIACO basin

**Boundary conditions for the CARIACO basin**

- Figures show the 2004 temperature average (space and time) for HYCOM and climatology (based on Levitus data) at northern model boundary

- Atlantic HYCOM

- Global NCODA HYCOM

- (Alvera-Azcarate and Weisberg)

**Notes:**
Correction of boundary values from HYCOM: top panel, NAT HYCOM used previously, bottom panel, new NCODA global HYCOM

## US West Coast HYCOM with Biology Nested in 1/12° Global HYCOM Basin

**Kindle et al. (NRL)**

**Notes:**
Basin-wide currents and gyre systems realistically represented.  Kuroshio that easily transitions between meander and straight path modes.

Boxes and lines are locations where model-data comparisons will be shown.

## COMPARISONS (Global Models)

- Global NCOM with SeaWIFS Chlorophyll: June 16 2004

- Global HYCOM with SeaWIFS Chlorophyll: June 16 2004

- Global NCOM SSH Anomaly
- June 16 2004

- Global HYCOM SSH Anomaly
-  June 16 2004

- Gridded Altimeter SSH-June 16 AVISO Product

- r= .8

- r= .76

- Gridded Altimeter SSH-June 16 NAVO Product

- Global NCOM SSH Anomaly
- June 16 2004

- Global HYCOM SSH Anomaly
-  June 16 2004

- (Kindle and deRada)

**Notes:**
Upwelling/Relaxation wind events well captured by atm forcing

## COMPARISONS (Global Models)

- Global NCOM with SeaWIFS Chlorophyll: June 16 2004

- Global HYCOM with SeaWIFS Chlorophyll: June 16 2004

- (Kindle and deRada)

**Notes:**
Upwelling/Relaxation wind events well captured by atm forcing

## Model Evaluation: Tide Gauges

**Global NCOM and HYCOM**

**Regional NCOM: Forced by NCOM  and HYCOM**

**Global HYCOM and NCOM nest represent Coastal Kelvin Wave Pulses More Accurately**

**Notes:**
Upwelling/Relaxation wind events well captured by atm forcing

## Model Evaluation: Tide Gauges

**Global NCOM and HYCOM**

**Regional NCOM: Forced by NCOM  and HYCOM**

**Global HYCOM and NCOM nest represent Coastal Kelvin Wave Pulses More Accurately**

**Notes:**
Upwelling/Relaxation wind events well captured by atm forcing

## Wetting and Drying in HYCOM

**Wetting and Drying ****in HYCOM**

## Wetting and Drying in HYCOM

**0 meter**
**layer **
**thickness**

**Baraille et al. (SHOM)**