Active and passive airborne microwave remote sensing for soil moisture retrieval in the Rur catchment, Germany. - Carsten Montzka; Sayeh Hasan; Heye Bogena; Irena Hajnsek; Ralf Horn; Thomas Jagdhuber; Andreas Reigber; Normen Hermes; Christoph Rüdiger; Harry Vereecken (IGARSS, 2012)