The overarching objective of 4DMED-Hydrology is to develop an advanced, high-resolution, and consistent reconstruction of the Mediterranean terrestrial water cycle through the use of high-resolution ESA satellite products. In particular, the project aims at: (i) describing and resolving the Mediterranean water cycle in its main components to better understand their relative contribution; (ii) advancing the Earth’s system science by investigating the strength of the land-atmosphere interactions, the human disturbance on the water cycle and the availability of water resources (e.g. groundwater) in the Mediterranean; and (iii) provide science-based tools compatible with decision making processes in order to strengthen the link between science and society, and in doing so improve water resources management.