GLEAM


GLEAM (Global Land Evaporation Amsterdam Model) is a set of algorithms that separately estimate the different components of land evaporation (or '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.

At NCI we replicated GLEAM V3 as part of the CABLE benchmarking collection (project wd9). The development of V3 started in 2017, since then 3 subversions were made available:  v3.1, v3.2 and v3.3, each one composed of two datasets, usually referred to as "a" and "b".

The GLEAM v3 includes:

  1. A new data assimilation scheme that has been validated for Australia (Martens et al., 2016) and that has been optimised to work at the global scale.
  2. An updated water balance module that describes the infiltration rates as a function of the vertical gradient in soil moisture.
  3. Updated evaporative stress functions that combine the vegetation optical depth and the root-zone soil moisture estimates.

This version is described in detail by Martens et al. (2017, GMD), listed in the acknowledgements section.

The most recent is v3.3, the key differences between the new datasets and v3.2 are:

  1. The v3.3a dataset is now produced using surface radiation and near-surface air temperature from the latest reanalysis of ECMWF, ERA5 (as opposed to ERA-Interim in v3.2a).
  2. Both GLEAM datasets are now produced using dynamic land cover information based on the MEaSUREs Vegetation Continuous Fields dataset (as opposed to a static map based on MODD44B v52 in the v3.2 datasets).
  3. All forcing datasets have been updated to their last versions and extended until the end of 2018. Due to the latency in CERES radiation data, GLEAM v3.3b only runs until September 2018.
  4. 4. Next to the daily-resolution data, both monthly and yearly datasets are available as well.

For more information refer to the GLEAM website

GLEAM on raijin

GLEAM datasets are part of the CABLE benchmarking collection and are part of the wd9 project, for each version # files are in:

/g/data/wd9/BenchMarking/GLEAM_v3-#/v3-#{a/b}

where the specific datasets are called "a" or "b" and in case of v1 also "c" .

To access this data currently you need to be part of the cable group, access for the cable group can be requested as for other group on https://my.nci.org.au, you might be asked though also to agreed to the cable group terms and conditions.

Access for the wd9 collection will change on the next few months following NCI re-organization of dataset projects.

License

Acknowledgements

Whenever GLEAM datasets are used in a scientific publication, the following references should be cited:

  1. Martens, B., Miralles, D.G., Lievens, H., van der Schalie, R., de Jeu, R.A.M., Fernández-Prieto, D., Beck, H.E., Dorigo, W.A., and Verhoest, N.E.C.: GLEAM v3: satellite-based land evaporation and root-zone soil moistureGeoscientific Model Development10, 1903–1925, doi: 10.5194/gmd-10-1903-2017, 2017.
  2. Miralles, D.G., Holmes, T.R.H., de Jeu, R.A.M., Gash, J.H., Meesters, A.G.C.A., Dolman, A.J.: Global land-surface evaporation estimated from satellite-based observationsHydrology and Earth System Sciences15, 453–469, doi: 10.5194/hess-15-453-2011, 2011.

Scientific use

GLEAM datasets will not be used for commercial purposes.

Feedback

Any feedback about the datasets and/or website are highly appreciated and can be sent through email to brecht.martens@ugent.be or diego.miralles@ugent.be.