NCEP Pacific Ocean Analysis

One-Line Description:

Hindcast results derived from a model based ocean analysis system.

Temporal Coverage:

Weekly means for 1992/08/02 - present.
Monthly means for 1980/01 - 2000/01.

Spatial Coverage:

1.0 degree latitude x 1.5 degree longitude global grid (81x112).
45.0N - 35.0S, 122.25E - 288.75E.

Levels:

Depth in centimeters at 500, 1500, 2500, 3500, 4500, 5500, 6500, 7500, 8500, 9500, 10625, 12000, 13625, 15500, 17750, 20500, 24000, 28500, 34500, 43000, 55000, 72000, 96750, 132750, 182100, 244350, 312650
Sea Surface

Update Schedule:

Weekly
Static

Download/Plot Data:

Variable	Statistic	Level	Download File
Ocean Temperature	Mean	Multiple	otemp.wkmean.nc otemp.mnmean.nc
Salinity	Mean	Multiple	salt.wkmean.nc salt.mnmean.nc
E-W Ocean Current	Mean	Multiple	ucur.wkmean.nc ucur.mnmean.nc
N-S Ocean Current	Mean	Multiple	vcur.wkmean.nc vcur.mnmean.nc
E-W Wind Stress	Mean	Surface	taux.wkmean.nc taux.mnmean.nc
N-S Wind Stress	Mean	Surface	tauy.wkmean.nc tauy.mnmean.nc
Surface Pressure Variation	Mean	Surface	ps.wkmean.nc ps.mnmean.nc
Short Wave Heat Flux	Mean	Surface	swfx.wkmean.nc
Heat Flux	Mean	Surface	hflx.wkmean.nc
Average Temperature Correction	Mean	Multiple	tc.wkmean.nc tc.mnmean.nc
Land Sea Depth	Mask	Surface	mask.wk.nc mask.mn.nc

Usage Restrictions:

None

Detailed Description:

The hindcast results are derived from a model based ocean analysis system. Observed surface and subsurface ocean temperatures as well as satellite altimetry sea-level data from TOPEX/POSEIDON are assimilated into a Pacific basin ocean general circulation model. The model is forced with weekly mean NCEP operational atmospheric analyses of surface winds and heat fluxes.

The analysis contains weekly and monthly means for temperature, salinity, u and v velocity components of ocean current all at multiple depths. Also included are weekly means for the surface variables east-west wind stress, north-south wind stress, surface pressure variation, short wave flux from NCEP's GDAS analysis and the heat flux. For the monthly means the surface variables east-west wind stress and north-south wind stress are included. Both monthly and weekly means includes the average temperature correction due to data assimilation. The monthly means are from the ocean reanalysis ra6.

Also included is a mask variable for both weekly and monthly means. The mask can vary with time to indicate values are available at a certain depth at some times and not at others. In the land mask array, value at each grid point indicates number of vertical levels of ocean at this grid point. Thus, a value of 0 indicates a land point, a value of 27 indicates this is an ocean point, and it has full ocean depth; a value of 10 indicates that this is an ocean point, but only the top 10 levels are in active ocean, the lower 17 levels are part of an under ocean mountain. Data variables at grid points shown to be invalid by the mask variable have been set to the missing value.

For more information see http://www.emc.ncep.noaa.gov/research/cmb/pac_analysis/.

Caveats:

Valid times are a week before the times in the NetCDF files.
Temperature correction from 1996/07/07 (valid time) on.
The date of record in the netCDF file is at the start of the average period.
Currently available week may be as much as a month behind the current date.
TOPEX altimitry data were used in the analysis after 1997.
(Short Wave Heat Flux) + (Heat Flux) = net heat flux

Related File Naming & Structure Information:

File Names:

var.time stat.nc (In directory: /Datasets/ncep.pac.ocean/)

Dataset Format and Size:

PSD standard NetCDF >350 Mbyte file for each multiple level weekly file (packed).
PSD standard NetCDF >13 Mbyte file for each single level weekly file (packed).
PSD standard NetCDF 118 Mbyte file for each multiple level monthly file (packed).
PSD standard NetCDF 4 Mbyte file for each single level monthly file (packed).
PSD standard NetCDF >26 Mbyte file for each pressure weekly file.
PSD standard NetCDF 9 Mbyte file for each pressure monthly file.

Missing Data:

Missing data is flagged with a value of 32767s.
Missing data is flagged with a value of -9.96921e+36f.

Citation:

Please note: If you acquire NCEP_Pac_Ocean data products from PSD, we ask that you acknowledge us in your use of the data. This may be done by including text such as NCEP_Pac_Ocean data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site at http://www.cdc.noaa.gov/ in any documents or publications using these data. We would also appreciate receiving a copy of the relevant publications. This will help PSD to justify keeping the NCEP_Pac_Ocean data set freely available online in the future. Thank you!

References:

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.
Ji, M., A. Leetmaa, and J. Derber, 1995: An ocean analysis system for seasonal to interannual climate studies. Mon. Wea. Rev., 123, 460-481.
Ji, M., and T. M. Smith, 1995: Ocean model response to temperature data and varying surface wind stress: Intercomparisons and Implications for climate forecast. Mon. Wea. Rev., 123, 1811-1821.

Original Source:

NOAA/NCEP/Environmental Modeling Center/Climate Modeling Branch Washington, D.C.

Contact:

Physical Sciences Division: Data Management
NOAA/ESRL/PSD
325 Broadway
Boulder, CO 80305-3328
esrl.psd.data@noaa.gov