Top-ranked geoscientist in the world according to the Institute for Scientific Information (ISI) based on 1997-2007 citations (2009); IGAC Keynote Lecture (2008); Ranked 16th "hottest researcher in the world" by the Institute for Scientific Information (ISI) on the basis of frequently cited papers (2005); NCAR Thompson Lecturer (2004); NASA Distinguished Public Service Medal (2003) "for outstanding seminal contributions to the understanding of fundamental physical and chemical processes in the lower atmosphere of the Earth"; NASA H. Julian Allen Award (1999) Editor's Citations for Excellence in Refereeing, Geophys. Res. Lett. (1999), J. Geophys. Res. (1991, 1998); James B. Macelwane Medal, American Geophysical Union (1994) "for significant contributions to the geophysical sciences by a young scientist of outstanding ability"; Fellow, American Geophysical Union (1994); Packard Fellowship for Science and Engineering (1989); Presidential Young Investigator Award (1988).