European scale, satellite-based irrigation water use estimates at 1 km spatial resolution

Irrigation is the most impactful yet less monitored human activity altering the natural hydrological cycle. In recent years, an ever-increasing number of studies have shown the potential of Earth Observation (EO) in tracking human dynamics along with natural ones, including estimates of irrigation water use (IWU). Particularly, the SM-Inversion method, a soil-water-balance approach adapted for quantifying IWU from satellite soil moisture, proved its skills across various scales of application. In this contribution, main results from the Irrigation-EU project will be presented. Its main objective is the development of the first ever European-scale, EO-based IWU data set. To do this, the SM-inversion algorithm has been optimized and implemented as operational Python processor. Features of the resulting IWU product include spatial and temporal resolutions equal to 1 km and 14-day, respectively. The temporal coverage spans from 2016 onwards. Operational input data has been leveraged for developing IWU estimates, i.e., Sentinel-1 soil moisture estimates delivered by the CLMS (Copernicus Land Monitoring Service) and total precipitation and potential evaporation from ERA5-Land (European ReAnalysis v5 – Land). Validation against reference irrigation volumes collected in several European case studies (mainly located in Spain, Italy, Greece, and Germany) will be presented. Moreover, the validation will benefit from the recently launched initiative which invites the scientific community to collaborate in developing the first database of in-situ IWU observations.