Global Land Evaporation Amsterdam Model
The Global Land Evaporation Amsterdam Model (GLEAM) is a set of algorithms that separately estimate the different components of land evaporation (often referred to as 'evapotranspiration’): transpiration, bare-soil evaporation, interception loss, open-water evaporation and sublimation. Additionally, GLEAM provides surface and root-zone soil moisture, potential evaporation and evaporative stress conditions.
The rationale of the method is to maximize the recovery of information on evaporation contained in current satellite observations of climatic and environmental variables.
The Priestley and Taylor equation in GLEAM calculates potential evaporation based on observations of surface net radiation and near-surface air temperature. Estimates of potential evaporation for the land fractions of bare soil, tall canopy and short canopy are converted into actual evaporation using a multiplicative evaporative stress factor based on observations of microwave Vegetation Optical Depth (VOD) and estimates of root-zone soil moisture. The latter are calculated using a multi-layer running-water balance. To try to correct for random forcing errors, observations of surface soil moisture are also assimilated into the soil profile. Interception loss is calculated separately in GLEAM using a Gash analytical model. Finally, estimates of actual evaporation for water bodies and regions covered by ice and/or snow are based on a modified Priestley and Taylor equation.
Extensive use of microwave observations, which provides an advantage under cloudy conditions.
Since its development in 2011, GLEAM has been continuously revised and updated. In 2017, a third version of the model (GLEAM v3) was published.
The GLEAM v3 includes:
This version is described in detail by Martens et al. (2017, GMD).
Version 3.5 datasets
Two datasets (v3.5a and v3.5b) which include the following 10 products:
These two datasets differ only in their forcing and temporal coverage:
Key differences between v3.5 and the previous (v3.3) release:
For more detailed information, users are directed to the readme file on the server or the FAQ.
The datasets described in the above section are freely available.
Whenever GLEAM v3 datasets are used in a scientific publication, the following references should be cited:
GLEAM datasets cannot be used for commercial purposes.
Selected publications using GLEAM data
Teuling, A.J., Taylor, C.M., Meirink, J.F., Melsen, L.A., Miralles, D.G., van Heerwaarden, C.C., Vautard, R., Stegehuis, A.I., Nabuurs, G.-J., de Arellano, J.V.-G.: Observational evidence for cloud cover enhancement over western European forests, Nature Communications, 8, 14065, 2017.
Zhang, Y., Peña-Arancibia, J.L., McVicar, T.R., Chiew, F.H.S., Vaze, J., Liu, C., Lu, X., Zheng, H., Wang., Y., Liu, Y.Y., Miralles, D.G., Pan M.: Multi-decadal trends in global terrestrial evapotranspiration and its components, Scientific Reports, 5, 19124, 2016.
. . . from the GLEAM front
GLEAM v3.5 datasets available
Why not 'evapotranspiration'?
Frequently Asked Questions