Restrictions | Details | Caveats | File Naming | Citation | References | Original Source | Contact
NCEP Global Ocean Data Assimilation System (GODAS)
- 5, 15, 25, 35, 45, 55, 65, 75, 85, 95, 105, 115, 125, 135, 145, 155, 165, 175, 185, 195, 205, 215, 225, 238, 262, 303, 366, 459, 584, 747, 949, 1193, 1479, 1807, 2174, 2579, 3016, 3483, 3972, 4478 m depth.
- 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 231, 250, 282, 334, 412, 521, 665, 848, 1071, 1336, 1643, 1990, 2376, 2797, 3249, 3727, 4225, 4736 m depth (for geometric vertical velocity only).
- Sea Surface
|Variable||Statistic||Level||Download File||Create Plot/Subset|
|Total downward heat flux at surface||Monthly Mean||Surface||List of thflx.*.nc files|
|Salt Flux||Monthly Mean||Surface||List of sltfl.*.nc files|
|Sea Surface Height Relative to Geoid||Monthly Mean||Surface||List of sshg.*.nc files|
|Geometric Depth Below Sea Surface||Monthly Mean||Isothermal Layer||List of dbss_obil.*.nc files|
|Geometric Depth Below Sea Surface||Monthly Mean||Mixing Layer||List of dbss_obml.*.nc files|
|Momentum flux, u component||Monthly Mean||Surface||List of uflx.*.nc files|
|Momentum flux, v component||Monthly Mean||Surface||List of vflx.*.nc files|
|Salinity||Monthly Mean||Multiple||List of salt.*.nc files|
|u-component of current||Monthly Mean||Multiple||List of ucur.*.nc files|
|v-component of current||Monthly Mean||Multiple||List of vcur.*.nc files|
|Geometric vertical velocity (dz/dt)||Monthly Mean||Multiple||List of dzdt.*.nc files|
|Potential temperature||Monthly Mean||Multiple||List of pottmp.*.nc files|
A detailed description can be found
here (pdf) from CPC. GODAS is a real-time ocean analysis and a reanalysis. It is used for monitoring, retrospective analysis as well as for providing oceanic initial conditions for the CFS. Both temperature and synthetic salinity profiles are assimilated in a 3DVAR scheme designed by Derber and Rosati (1989). 40 vertical levels are in the model together with 1x1 data values (enhanced in resolution to 1/3x1/3 degrees latitude within 10 degrees of the equator).
The data is provided at 1/3x1/3 degrees for all latitudes.
The GODAS is forced by the momentum flux, heat flux and fresh water flux
from the NCEP atmospheric Reanalysis 2. It appears to reproduce observations quite well (see the references).
In the GODAS/MOM3 archive distribution there are two fields having to do with vertical mixing, a "mixed layer depth", dbss_obml, and a "boundary layer depth", hblt. Both parameters are products of the KPP mixing scheme. The mixed layer depth is the depth where the buoyancy difference with respect to the surface level is equal to 0.03 (cm/s2). The boundary layer depth is the depth where the bulk richardson number is equal to the critical value of 0.3. In the GRIB distribution the boundary layer depth is mislabeled as an isothermal layer, which is, unfortunately, confusing.
- var.yyyy.nc (In directory: /Datasets/godas)
OpenDap File Names:
Dataset Format and Size:
- PSL standard NetCDF 3.6 Mbyte file for each yearly single layer monthly mean file (packed).
- PSL standard NetCDF ~144 Mbyte file for each yearly multi-level monthly mean file (packed).
- Missing data is flagged with a value of 32767s.
- Behringer, D.W., and Y. Xue, 2004: Evaluation of the global ocean data assimilation system at NCEP: The Pacific Ocean. Eighth Symposium on Integrated Observing and Assimilation Systems for Atmosphere, Oceans, and Land Surface, AMS 84th Annual Meeting, Washington State Convention and Trade Center, Seattle, Washington, 11-15.
- Please note: If you acquire GODAS data products from PSL, we ask that you acknowledge us in your use of the data. This may be done by including text such as GODAS data provided by the NOAA/OAR/ESRL PSL, Boulder, Colorado, USA, from their Web site at / in any documents or publications using these data. We would also appreciate receiving a copy of the relevant publications. This will help PSL to justify keeping the GODAS data set freely available online in the future. Thank you!
- Behringer, D.W., M. Ji, and A. Leetmaa, 1998: An improved coupled model for ENSO prediction and implications for ocean initialization. Part I: The ocean data assimilation system. Mon. Wea. Rev., 126, 1013-1021.
- Behringer, D.W., and Y. Xue, 2004: Evaluation of the global ocean data assimilation system at NCEP: The Pacific Ocean. Eighth Symposium on Integrated Observing and Assimilation Systems for Atmosphere, Oceans, and Land Surface, AMS 84th Annual Meeting, Washington State Convention and Trade Center, Seattle, Washington, 11-15. Derber, J.C., and A. Rosati, 1989: A global oceanic data assimilation system. J. Phys. Oceanogr., 19, 1333-1347.
- Ji, M., A. Leetmaa, and J. Derber, 1995: An ocean analysis system for seasonal to interannual climate studies. Mon. Wea. Rev., 123, 460-481.
- S. Saha, S. Nadiga, C. Thiaw, J. Wang, W. Wang, Q. Zhang, H. M. van den Dool, H.-L. Pan, S. Moorthi, D. Behringer, D. Stokes, M. Peľa, S. Lord, G. White, W. Ebisuzaki, P. Peng, P. Xie , 2006 : The NCEP Climate Forecast System. Accepted J. Climate.
- NOAA Climate Prediction Center from http://www.cpc.ncep.noaa.gov/products/GODAS/.
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