README file for Global Forecast System (GFS) analysis files This directory contains global analysis fields from the NCEP operational Global Forecast System (GFS) model for the period preceding and during the START08 field program. The NCEP files are in GRIB format, compressed with bzip2. For easier access with user-developed software, selected variables were copied to netCDF files. Both GRIB and netCDF files are stored in the project archive. The files provided by NCEP are in pressure coordinates. Variables were interpolated by NCEP from the model's terrain following coordinate. Data properties Spatial coverage Global Start time 2008-03-01 00Z End time 2008-08-04 12Z Time interval 6 hours, 1 time step per file Grid dimensions (lon x lat x pressure) 1152 x 576 x 47 Gaussian grid Grid resolution (lon x lat x pressure) 0.3125 deg x ~0.3125 deg x ~25 hPa GRIB file size (compressed) ~310 MB GRIB file size (uncompressed) ~555 MB NetCDF file size (uncompressed) 863.2 MB For further information contact: Prof. Kenneth P. Bowman Department of Atmospheric Sciences 3150 TAMU Texas A&M University College Station, TX 77843-3150 k-bowman@tamu.edu NCDUMP of sample file stretch> ncdump -h gfs_20080301T00Z.ncd netcdf gfs_20080301T00Z { dimensions: Longitude = 1152 ; Latitude = 576 ; Altitude = 47 ; date_string = 20 ; Time = UNLIMITED ; // (1 currently) variables: float Longitude(Longitude) ; Longitude:delta = 0.3125 ; Longitude:long_name = "Longitude" ; Longitude:units = "degrees" ; float Latitude(Latitude) ; Latitude:delta = -0.3096085f, -0.3114395f, -0.3118515f, ... -0.3114395f, -0.3096085f ; Latitude:long_name = "Latitude" ; Latitude:units = "degrees" ; float Altitude(Altitude) ; Altitude:delta = -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -25.f, -30.f, -20.f, -20.f, -10.f, -10.f, -3.f, -2.f, -2.f, -1.f, -1.f ; Altitude:long_name = "Pressure" ; Altitude:units = "hPa" ; char Time(Time, date_string) ; Time:delta = 0 ; Time:long_name = "Date and time in ISO 8601 long UTC format" ; Time:units = "YYYY-MM-DD 00:00:00Z" ; char Analysis_time(Time, date_string) ; Analysis_time:delta = 0 ; Analysis_time:long_name = "Analysis date and time in ISO 8601 long UTC format" ; Analysis_time:units = "YYYY-MM-DD 00:00:00Z" ; float u(Time, Altitude, Latitude, Longitude) ; u:long_name = "U-component of the velocity" ; u:units = "m s^-1" ; float v(Time, Altitude, Latitude, Longitude) ; v:long_name = "V-component of the velocity" ; v:units = "m s^-1" ; float w(Time, Altitude, Latitude, Longitude) ; w:long_name = "W-component of the velocity" ; w:units = "hPa s^-1" ; float Z(Time, Altitude, Latitude, Longitude) ; Z:long_name = "Geopotential height" ; Z:units = "m" ; float T(Time, Altitude, Latitude, Longitude) ; T:long_name = "Temperature" ; T:units = "K" ; float vor(Time, Altitude, Latitude, Longitude) ; vor:long_name = "Vorticity" ; vor:units = "s^-1" ; float RH(Time, Altitude, Latitude, Longitude) ; RH:long_name = "Relative humidity" ; RH:units = "%" ; float Z_trop(Time, Latitude, Longitude) ; Z_trop:long_name = "Geopotential height of the tropopause" ; Z_trop:units = "m" ; float T_trop(Time, Latitude, Longitude) ; T_trop:long_name = "Temperature at the tropopause" ; T_trop:units = "K" ; float p_trop(Time, Latitude, Longitude) ; p_trop:long_name = "Pressure at the tropopause" ; p_trop:units = "Pa" ; float u_trop(Time, Latitude, Longitude) ; u_trop:long_name = "Zonal wind at the tropopause" ; u_trop:units = "m s^-1" ; float v_trop(Time, Latitude, Longitude) ; v_trop:long_name = "Meridional wind at the tropopause" ; v_trop:units = "m s^-1" ; float Z_sfc(Time, Latitude, Longitude) ; Z_sfc:long_name = "Surface geopotential height" ; Z_sfc:units = "m" ; float T_sfc(Time, Latitude, Longitude) ; T_sfc:long_name = "Surface temperature" ; T_sfc:units = "K" ; float lftx_sfc(Time, Latitude, Longitude) ; lftx_sfc:long_name = "4-layer Surface lifted index" ; lftx_sfc:units = "K" ; float mslp(Time, Latitude, Longitude) ; mslp:long_name = "Sea level pressure" ; mslp:units = "Pa" ; float pwat(Time, Latitude, Longitude) ; pwat:long_name = "Precipitable Water" ; pwat:units = "kg/m^2" ; float u_sfc(Time, Latitude, Longitude) ; u_sfc:long_name = "Surface u" ; u_sfc:units = "m s^-1" ; float v_sfc(Time, Latitude, Longitude) ; v_sfc:long_name = "Surface v" ; v_sfc:units = "m s^-1" ; }