A. Data are integrated within GLDAS as static parameter fields, as meteorological forcing, and through the process of data assimilation. Parameter fields include vegetation type and properties derived from AVHRR and MODIS, soil properties from the USDA, and elevation from GTOPO30 (see GLDAS vegetation page). Meteorological forcing datasets include downscaled Global Precipitation Climatology Project (GPCP) precipitation, Air Force Weather Agency solar radiation, and NOAA Global Data Assimilation System (GDAS) air temperature, surface pressure, wind speed, land specific humidity (see GLDAS forcing page).
Currently, the only data that GLDAS integrates through data assimilation is GRACE terrestrial water storage in the 0.25 degree Catchment LSM simulation in GLDAS-2.2. We assimilate GRACE data into a separate simulation of the Catchment model which is then used to diagnose drought. For more information, see the NDMC website.