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You are here: GES DISC Home Hydrology Data Holdings NLDAS Parameters TOTAL EVAPOTRANSPIRATION


Other Names



Total Evapotranspiration (ET) is the sum of evaporation and plant transpiration. Evaporation accounts for the movement of water to the air from various sources on earth surface such as soil, ocean, etc. Transpiration accounts for the movement of water within a plant and the subsequent loss of water as vapors through stomata in its leaves.

The evapotranspiration rate expresses the amount of water lost from a unit area of surface per unit time. The time unit can be an hour, day, month, year, and even decade.

There are four components of the total evapotranspiration in the NLDAS-2 model data. They are as follows (with PDS ID number, variable names, full description, and units):

    199:EVBSsfc:Direct evaporation from bare soil [W/m^2]
    200:EVCWsfc:Canopy water evaporation [W/m^2]
    198:SBSNOsfc:Sublimation (evaporation from snow) [W/m^2]
    210:TRANSsfc:Transpiration [W/m^2]

The components are also defined as positive in the downward direction, which means that the sum of these four components is equal to the negative of the latent heat flux for NLDAS-2 Mosaic and Noah models:

    121:LHTFL:Latent heat flux [W/m^2]

Additionally, another term for the total evapotranspiration (in mass units) can be found here:

057:EVP:Evaporation [kg/m^2]

Also see:


  1. Water cycle
  2. Energy cycle
  3. Weather forecast
  4. Climate prediction model

GES DISC Datasets

To access products that have a specific parameter click on the corresponding 'data access' links in the table below.

Parameter Units Platform /Instrument Data
Begin Date End Date Access Doc
Total Evapotranspiration kg/m^2 NLDAS Model 1979 present ftp Y

Other sources for data

  1. NLDAS


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Last updated: Jun 17, 2014 11:56 AM ET