AGU member since 1978. Ralph J. Cicerone Distinguished University Professor of Atmospheric Science, University of Michigan, Ann Arbor.

Volunteer experience includes vice president, International Association of Meteorology and Atmospheric Science (2011–2015); chair-elect, chair, and retiring chair, American Association for the Advancement of Science section on atmospheric and hydrospheric sciences (2005–2008); chair/member, AGU Macelwane Award Selection Committee (2008–2012); member, AGU Publications Committee (2004–2008); review editor, technical summary, Intergovernmental Panel on Climate Change (IPCC) Working Group I Fifth Assessment Report; review editor, Chapter 7: Clouds and Aerosols, IPCC Working Group I Fifth Assessment Report.