This data set contains a series of land surface parameters simulated from the Catchment model experiment 001, for Version 2 of the Global Land Data Assimilation System (GLDAS-2). The data are in 1.0 degree resolution and range from January 1948 to the present. The temporal resolution is 3 hourly.
The model simulation was initialized on simulation date January 1, 1948, using soil moisture and ... other state fields from the LSM climatology for that day of the year. The simulation was forced by the global meteorological forcing data set from Princeton University (Sheffield et al., 2006). The simulation used the common GLDAS data sets for land cover (UMD: Hansen, 2000), soil texture (Reynolds, 1999), and elevation (GTOPO30).
The main objective for Version 2 is to create more climatologically consistent data sets using the Princeton forcing data sets extending from 1948. In Version 1, forcing sources switched several times throughout the record from 1979 to present, which introduced unnatural trends and exhibited highly uncertain forcing fields in 1995-1997. Other enhancements made in Version 2 include initialization of soil moisture over desert and bottom layer temperature.
WGRIB or other GRIB reader is required to read the files. The data set applies a user-defined parameter table to indicate the contents and parameter numbers. The following table shows a list of parameters, their Product Definition Section (PDS) IDs and units.
PDS_IDs Full_Name Unit
1 Surface pressure Pa
11 Near surface air temperature K
32 Near surface wind speed m/s
51 Near surface specific humidity kg/kg
57 Total Evapotranspiration kg/m^2/s
65 Snow water equivalent kg/m^2
85 Soil temperature K
86 Average layer soil moisture content kg/m^2
99 Snowmelt kg/m^2/s
111 Net shortwave radiation W/m^2
112 Net longwave radiation W/m^2
121 Latent heat flux W/m^2
122 Sensible heat flux W/m^2
148 Average surface temperature K
155 Ground heat flux W/m^2
161 Snowfall rate kg/m^2/s
162 Rainfall rate kg/m^2/s
204 Surface incident shortwave radiation W/m^2
205 Surface incident longwave radiation W/m^2
223 Plant canopy surface water kg/m^2
234 Subsurface runoff kg/m^2/s
235 Surface runoff kg/m^2/s
There are three vertical levels for the Soil Moisture (PDS 086) and six vertical levels for Soil Temperature (PDS 085) in the GRIB file. For more information, please see ftp://hydro1.gsfc.nasa.gov/data/s4pa/GLDAS/README.GLDAS-2.pdf