- June 2013 – current: Full Professor of Earth and Environmental Sciences, Vanderbilt University. Affiliate Professor at the University of Wisconsin – Madison’s Department of Atmospheric and Oceanic Sciences and at the UW-Madison Space Science and Engineering Center.
- December 2011 – May 2013: Full Professor at the Department of Atmospheric and Oceanic Sciences and Principal Investigator Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin – Madison.
- June 2007 – November 2012: Associate Professor at the Department of Atmospheric and Oceanic Sciences and Principal Investigator Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin – Madison.
- September 2002 – May 2007: Assistant Professor at the Department of Atmospheric and Oceanic Sciences, University of Wisconsin – Madison.
- January 2001 – August 2002: Assistant Professor at the Department of Physics and Astronomy, University of Kansas. Associate Scientist at Free University of Berlin, Institute for Space Sciences.
- June 1997 – December 2000: Research Scientist at the Institute for Space Sciences, Free University of Berlin, Germany.
- University of Cologne, Germany, Undergraduate studies in Atmospheric Sciences, 1988-1990
- University of Hamburg/Max-Planck-Institute für Meteorologie, Hamburg, Germany. Diploma (equiv. M.S. degree) in Meteorology obtained at the Subject: A simulation study on cloud/radiation interaction in stratocumulus clouds. April 1994
- The Free University of Berlin, Institute for Space Sciences. Ph.D. at. Subject: Retrieval of rain, cloud, and humidity parameters from passive microwave data in coastal regions. May 1997.
- Expert Reviewer Intergov. Panel on Climate Change, Working Group 1, 5th Assessment Report
- Member American Meteorological Society Radiation Committee
- Editor of the Journal of Applied Meteorology and Climatology (JAMC). 2006 – 2010.
- Chair, JCSDA Working Group on Cloud and Precipitation Data Assimilation 2011-2015
- Chair of workshop series ‘International Workshop on Space-based Snowfall Measurements’, 2007,2009, 2011,2013.
- Member of various international scientific working groups and science teams, including the International Tyros Operational Vertical Sounder (TOVS) Working Group (ITWG), International Precipitation Working Group (IPWG).
- NASA Precipitation Measurement Mission (PMM), CloudSat, and OCO-2 Science Team Member, GEWEX Water Vapor Assessment G-VAP, ESA Arctic Product Validation and Evolution (APVE) program.