Earth system models have contributed significantly to improving the understanding of the dynamics of the global water cycle. However, these models indicate limitations due to the uncertainty of input data, boundary conditions of the model, parameterisation for model simplifications, and imperfect model structure.

DATA ASSIMILATION AND MODEL PARAMETER CALIBRATION TECHNIQUES

Earth Observation (EO) satellite missions provide invaluable estimates of atmospheric, hydrological, and biophysical variables, which often cover the entire globe.

From these EO missions, the Gravity Recovery and Climate Experiment (GRACE) and its follow-on mission (GRACE-FO) measurements can be used to estimate Terrestrial Water Storage Changes (TWSC), i.e. a vertical summation of surface and sub-surface water storage changes.

In addition, various satellite missions provide multi-decadal Surface Soil Moisture (SSM) estimates, as well as Land Surface Temperature. These missions include SMOS, SMAP, MODIS, and Sentinel, which typically measure electromagnetic radiance emitted by the Earth surface or sample waveforms returned from radar pulses. However, the relationship between the measured radiance or waveforms and the quantities of interest might be incredibly complex.

Therefore, a strategic step for the Earth sciences involves merging remote sensing data and models via data assimilation and model parameter calibration techniques.

CALCULATION AND PREDICTION OF THE TOTAL WATER SUPPLY

The aim of AssimEO is the calculation and prediction of the total water supply for plant production through assimilation of EO data into a hydrological model. Details on the temporal and spatial dynamic of water supply in the

1. Few upper centimeters of the soil
2. Root-zone layer of the soil
3. Groundwater storage, as well as
4. Summary of all components will be provided

The project is a collaboration between Assistant Professor Maike Schumacker from Aalborg University, Dr. Carsten Montzka from Forschungszentrum Jülich GmbH and Dr. Thomas Jagdhuber from German Aerospace Center (DLR).