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About the Atlantic RTOFS GRiB

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Atlantic RTOFS produces a number of different GRiB files. Surface fields are produced every hour and full-volume fields are produced every 24 hours. A 24-hour nowcast, or analysis, is run and is followed by forecasts out to 120 hours.

For the full-volume gribs we produce two distinctly different types. The first type contain the model data referenced to the native horizontal grid and the vertical hybrid coordinates. The second type is also referenced on the native horizontal grid but the vertical coordinates have been interpolated to 40 fixed depths.

For the surface gribs we produce two different types as well. The first type are the surface values on the native horizontal grid while the second type are gribs that have been interpolated to a rectangular (or standard) latitude-longitude grid. Finally, some of the standard lat/lon GRiB files have been subsetted, or reduced to a smaller domain. The subdomain is indicated with an abbreviation as part of the file name.

More information on the model grids defined in the Atlantic RTOFS GRiB files can be found in the NCO Master List of NCEP Storage Grids.

Atlantic RTOFS GRiB file name conventions

  • ofs_atl.t00z.[lnnn].[3d].[region1].grb - hybrid curvilinear coord. system grid
  • ofs_atl.t00z.[lnnn].[region2].grb.std - interpolated to standard lat-lon grid

  • where
  • l = nowcast/forecast and surface/volume indicator:
    • n - nowcast surface fields only
    • N - nowcast full volume fields
    • f - forecast surface fields only
    • F - forecast full volume fields
  • nnn = the forecast hour. For nowcasts, these numbers start at -23 and go forward to 000 (n-23, n-22, n-21, ... n-02, n-01, n000).
  • 3d = if present then the grib file contains all the fields and on the native grid.
  • region1 = the files are subsetted to a smaller region (if no region is specified in the filename then it the grib is the full Atlantic basin). The subdomain abbreviations are as follows:
    • g_mx - Gulf of Mexico
    • nw_atl_north - Northwest northern Atlantic
    • nw_atl_mid - Northwest middle Atlantic
    • nw_atl_south - Northwest southern Atlantic
  • region2 =
    • atl - full basin
    • gm - Gulf of Mexico
    • gma - Gulf of Maine
    • gs - Gulf Stream region

GRiB file name examples

GRiB file name Description
ofs_atl.t00z.F024.grb24 hour forecast, full volume at Z-levels
ofs_atl.t00z.F024.3d.grb24 hour forecast, full volume at native levels
 
ofs_atl.t00z.F024.3d.g_mx.grb24 hour forecast, full volume, gulf of mexico region at native levels
ofs_atl.t00z.F024.3d.nw_atl_mid.grb24 hour forecast, full volume, middle Atlantic region at native levels
ofs_atl.t00z.F024.3d.nw_atl_north.grb24 hour forecast, full volume, northern Atlantic region at native levels
ofs_atl.t00z.F024.3d.nw_atl_south.grb24 hour forecast, full volume, southern Atlantic region at native levels
 
ofs_atl.t00z.f001.grb1 hour surface, partial set
ofs_atl.t00z.f001.3d.grb1 hour surface, all fields
 
ofs_atl.t00z.f001.3d.g_mx.grb1 hour forecast, surface, Gulf of Mexico region
ofs_atl.t00z.f001.3d.nw_atl_mid.grb1 hour forecat, surface, middle Atlantic region
ofs_atl.t00z.f001.3d.nw_atl_north.grb1 hour forecat, surface, northern Atlantic region
ofs_atl.t00z.f001.3d.nw_atl_south.grb1 hour forecat, surface, southern Atlantic region
 
ofs_atl.t00z.f001.atl.grb.std1 hour forecast, lat-lon grid, Atlantic basin
ofs_atl.t00z.f001.gm.grb.std1 hour forecast, lat-lon grid, Gulf of Mexico region
ofs_atl.t00z.f001.gma.grb.std1 hour forecast, lat-lon grid, Gulf of Maine region
ofs_atl.t00z.f001.gs.grb.std1 hour forecast, lat-lon grid, Gulf Stream region

Atlantic RTOFS GRiB Parameter Names and Definitions

Daily full-basin volumetric fields, native horizontal coordinates, fixed-depth vertical coordinates
(ofs_atl.t00z.N000.grb, ofs_atl.t00z.F024.grb)

Parameter Name Definition [units]
DZDTGeometric vertical velocity [m/s] - 40 Z-levels
SSHGSea Surface Height Relative to Geoid [m]
MIXHTMixed layer depth [m]
UOGRDu of current [m/s] - 40 Z-levels
VOGRDv of current [m/s] - 40 Z-levels
WTMPCIn-situ Temperature [C] - 40 Z-levels
SALINSalinity [psu] - 40 Z-levels
LOUVLongitude of U wind component of velocity [deg]
LAUVLatitude of U wind component of velocity [deg]
LOVVLongitude of V wind component of velocity [deg]
LAVVLatitude of V wind component of velocity [deg]
LOPPLongitude of pressure point [deg]
LAPPLatitude of pressure point [deg]

Daily volumetric fields, native horizontal coordinates, hybrid vertical coordinates
(ofs_atl.t00z.N000.3d.grb, ofs_atl.t00z.F024.3d.grb, ofs_atl.t00z.F024.3d.[region1].grb)

Parameter Name Definition [units]
EMNPEvaporation - Precipitation [cm/day]
LHTFLLatent heat flux [W/m^2]
SHTFLSensible heat flux [W/m^2]
SSHGSea Surface Height Relative to Geoid [m]
MNTSFMontgomery stream function [m^2/s^2]
UMLUU Velocity in mixed layer [m/s]
UMLVV Velocity in mixed layer [m/s]
MIXHTMixed layer depth [m]
OMLTMixed Layer Potential Temperature [C]
OMLSSalinity [psu]
OMLPOTDENOcean Mixed Layer Potential Density (Referenced to 2000m) [kg/m^3]
UBAROBarotropic U Velocity [m/s]
VBAROBarotropic V Velocity [m/s]
UOGRDu of current [m/s] - native levels
VOGRDv of current [m/s] - native levels
LAYTHLayer Thickness[m] - native levels
WTMPCPotential Temperature [C] - native levels
SALINSalinity [psu] - native levels
DENDensity [kg/m^3] - native levels
LOUVLongitude of U wind component of velocity [deg]
LAUVLatitude of U wind component of velocity [deg]
LOVVLongitude of V wind component of velocity [deg]
LAVVLatitude of V wind component of velocity [deg]
LOPPLongitude of pressure point [deg]
LAPPLatitude of pressure point [deg]

Hourly full basin surface fields, native horizontal coordinates, fixed depth vertical coordinates
(ofs_atl.t00z.n-23.grb, ofs_atl.t00z.n000.grb, ofs_atl.t00z.f001.grb)

Parameter Name Definition [units]
SSHGSea Surface Height Relative to Geoid [m]
MNTSFMontgomery stream function [m^2/s^2]
MIXHTMixed layer depth [m]
UBAROBarotropic U Velocity [m/s]
VBAROBarotropic V Velocity [m/s]
UOGRDu of current [m/s]
VOGRDv of current [m/s]
WTMPCIn-situ Temperature [C]
SALINSalinity [psu]
LOUVLongitude of U wind component of velocity [deg]
LAVVLatitude of U wind component of velocity [deg]
LOVVLongitude of V wind component of velocity [deg]
LAVVLatitude of V wind component of velocity [deg]
LOPPLongitude of pressure point [deg]
LAPPLatitude of pressure point [deg]

Hourly surface fields, native horizontal coordinates, hybrid vertical coordinates
(ofs_atl.t00z.f001.3d.grb, ofs_atl.t00z.f001.3d.[region1].grb)

Parameter Name Definition [units]
EMNPEvaporation - Precipitation [cm/day]
LHTFLLatent heat flux [W/m^2]
SHTFLSensible heat flux [W/m^2]
SSHGSea Surface Height Relative to Geoid [m]
MNTSFMontgomery stream function [m^2/s^2]
OMLUU Velocity in mixed layer [m/s]
OMLVV Velocity in mixed layer [m/s]
MIXHTOcean Mixed layer depth [m]
OMLTOcean Mixed Layer Potential Temperature [C]
OMLSOCean Mixed Layer Salinity [psu]
OMLPOTDENOcean Mixed Layer Potential Density (Referenced to 2000m) [kg/m^3]
UBAROBarotropic U Velocity [m/s]
VBAROBarotropic V Velocity [m/s]
UOGRDu of current [m/s]
VOGRDv of current [m/s]
LAYTHLayer Thickness[m]
WTMPCPotential Temperature [C]
SALINSalinity [psu]
DENDensity [kg/m^3]
LOUVLongitude of U wind component of velocity [deg]
LAUVLatitude of U wind component of velocity [deg]
LOVVLongitude of V wind component of velocity [deg]
LAVVLatitude of V wind component of velocity [deg]
LOPPLongitude of pressure point [deg]
LAPPLatitude of pressure point [deg]

Daily surface fields, rectangular lat/lon horizontal coordinates
(ofs_atl.t00z.f001.[region2].grb.std)

Parameter Name Definition [units]
WTMPPotential Water Temp. [K]
DSLMDeviation of sea level from mean [m]
SALTYSalinity [kg/kg]
UOGRDu of current [m/s]
VOGRDv of current [m/s]

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Page last modified: Friday, 05-Oct-2012 19:15:13 UTC