Anne Felsberg, Katholieke Universiteit Leuven, Department of Earth and Environmental Sciences, Leuven, Belgium, Gabrielle De Lannoy, KU Leuven, Department of Earth and Environmental Sciences, Heverlee, Belgium, Manuela Girotto, UC Berkeley, Berkeley, CA, United States, Rolf H Reichle, NASA Goddard Space Flight Center, Greenbelt, MD, United States and Jean William Poesen, Katholieke Universiteit Leuven, Leuven, Belgium