CHIRPS Precipitation, Copernicus DEM, (Ag)ERA5 Meteorological Data, GEOS-5 Meteorological Data, IMERG Precipitation, Landsat satellites, MODIS sensors, MSG satellites, Sentinel-2 satellites, VIIRS sensors and WorldCover Land Cover

GEOS-5

The Goddard Earth Observing System Model, Version 5 (GEOS-5) uses the Earth System Modeling Framework (ESMF). The GEOS-5 Data Assimilation System (GEOS-5 DAS) integrates the GEOS-5 Atmospheric Global Climate Model (GEOS-5 AGCM) with the Gridpoint Statistical Interpolation (GSI) atmospheric analysis developed jointly with NOAA/NCEP/EMC.

Purpose of data

This data is used to produce Weather data input to create NRT NPP and relative soil moisture content for Level 1, 2 and 3. For the final data processing the meteorological data is derived from (Ag)ERA5. Furthermore specific GEOS-5 parameters are used for atmospheric corrections, to estimate shortwave radiation at L1 (and as back up for level 2 and level 3), and to provide the precipitation data feeding into the Interception calculations for level 1 (and as backup for level 2 and level 3).

Approach

The GEOS-5 systems are being developed by the Global Modeling and Assimilation Office (GMAO) to support NASA's earth science research. The data are sourced from the NASA NCCS Dataportal. Data is freely available with a time-step of 6 hours. GEOS-5 data is available from 21 February 2014.

GEOS-5 parameters used are:
- Air temperature at 2m (t2m)
- Surface pressure is derived from sea level pressure [slp] and corrected for altitude using the DEM.
- Relative humidity is derived from actual vapor pressure and saturated vapor pressure calculated using GEOS-5 specific humidity at 2 m above the displacement height [qv2m], GEOS-5 sea level pressure [slp], and air temperature at 2m [t2m].
- Wind speed is derived from eastward [u10m] and northward [v10m] wind speed components.
- For atmospheric correction we use clear-sky radiation derived using GEOS5 total column water vapor [tqv], atmospheric water vapor [wv_i] and aerosol optical depth at 550nm [aod550_i] - Shortwave radiation is derived from the surface incident shortwave flux (swgdn).

Challenges

The coarse resolution of the data makes it impossible to obtain location-specific meteo data. In mountainous regions corrections are made for elevation (lapse-rate correction of temperature) using a digital elevation model.

Alternative sources

• MERRA for the period spanning 1979 to February 2016
• ERA5 and AgERA5 from 1979 to present (not yet available at the start of WaPOR version 2)