Stefania Camici¹, Luca Brocca², Christian Massari², Gabriele Giuliani³, Nico J Sneeuw⁴, Hassan Hashemi Farahani⁵, Marco Restano⁶ and Jérôme Benveniste⁷, (1)CNR-IRPI National Research Council, Bari, Italy, (2)Research Institute for Geo-Hydrological Protection National Research Council CNR, Perugia, Italy, (3)CNR IRPI, Perugia, Italy, (4)University of Stuttgart, Stuttgart, Germany, (5)Institute of Geodesy, University of Stuttgart, Stuttgart, Germany, (6)European Space Agency, Frascati, Italy, (7)European Space Agency (ESA-ESRIN), Earth Observation Programmes, Frascati, Italy