Earth Explorer 10 Candidate Mission Hydroterra, Report for Assessment

Satellites are part of daily life, so it's surprising to realise that there are still important gaps in the services they provide. Hydroterra will pioneer continuous radar imaging over Europe and Africa so that rapid weather and land surface processes can be imaged to reveal new science and enable important new services. Hydroterra is a novel mission concept which offers a remarkable range of capabilities and which could have a significant impact on the sciences of weather forecasting, hydrology, and the mountain cryosphere, as well as providing direct benefits to society. The mission focusses on capturing and understanding relatively rapid land-atmosphere processes related to the water cycle and the solid Earth. Hydroterra is designed to help scientists unravel details of the daily water cycle. Some of the main challenges come from processes which occur over periods of a few hours and at local, kilometre, scale. Current satellites may provide only 1-2 images per week, or have such large footprints that details of the local weather patterns are difficult to resolve. These challenges led to the definition of the following science goals for the Hydroterra mission: - Capture and understand these fast processes for improving the modelling capability for intense rainfall and related flooding and landslides, - Improve understanding of the diurnal water cycle related to soil moisture and snow melt/re-freeze, - Enable near real-time acquisition and analysis of ground motion (and response management) for landslides, earthquakes and volcanoes.