Vincenzo Levizzani is retired as Director of Research at the National Research Council of Italy. He has taught cloud physics at the University of Bologna for more than 20 years. His research focuses on the structure of precipitating systems, the physics of intense storms using radar and satellites, satellite precipitation estimation, severe weather analysis, and climatology of precipitation. He has led, as chairman, several expert groups at WMO, EUMETSAT and satellite planning groups for Meteosat Third Generation and EUMETSAT Polar Satellite Second Generation. He was co-founder of the International Precipitation Working Group, an international organisation with more than 500 members. He has also led several research projects of the European Commission. His publications consist of more than 200 papers in peer reviewed literature and several books. Christopher Kidd is a research scientist at the Earth System Science Interdisciplinary Center at the University of Maryland and at NASA’s Goddard Space Flight Center. Before moving to the US, he was a senior lecturer at the University of Birmingham in the UK where he taught applied meteorology and climatology and Earth observation. The focus of his research centres on the observation of precipitation from surface and satellite sensors, the intercomparison and validation of precipitation measurements and the development of new satellite systems for precipitation estimation. He has been a member of a number of advisory groups for EUMETSAT, ESA and NASA, has been a co-chair of the International Precipitation Working Group, is a co-lead for the Precipitation Virtual Constellation of the Committee on Earth Observation Satellites, and is a member of the National Academies Committee on Radio Frequencies. His research has been funded by NASA, NOAA, EUMETSAT, ESA, Natural Environment Research Council, and the European Commission. He has published over 100 papers, book chapters and books in internationally peer reviewed literature.