Earth Observation integrated modelling tool for description of the water balance and runoff production of the Tibetan Plateau

Quantifying the spatial and temporal relationships between the different water balance terms for the entire Tibetan Plateau is a key-focus of the CEOP-AEGIS project funded by the 7th Framework Programme of the European Commission. One of the products of this project will be a prototype water balance observation system for the Tibetan Plateau, built as an integrated platform between Earth Observation products and a distributed water balance and runoff model. The prototype package will provide a quantification of the water yield being supplied to the downstream areas and it will be also used to evaluate the effects of climate change on the water yield of the Plateau. As a requirement, it will rely on an existing and expanding network of observatories and on space-borne observing systems for which data continuity is guaranteed. Earth Observation-based input will include evapotranspiration fluxes, precipitation, snowmelt and top soil moisture. Following a comparative analysis among different modelling approaches, the raster-based modelling environment PC-Raster, developed at Utrecht University, has been chosen to develop the prototype. The model PCR-GLOBWB of the Tibetan Plateau will be applied to an area of over 1.2 × 10⁶ km², between 27.20 and 36.70 degrees latitude and 78.20 and 99.10 degrees longitude, bordering India, Nepal and Bhutan. For a preliminary validation of PCR-GLOBWB, daily streamflow data for 2009 in a section of the Upper Yellow River have been considered, with actual evapotranspiration derived from MODIS and precipitation from TRMM.