My research focuses on the use models and observations to understand the roles of atmospheric aerosols in the Earth system, with specializations in modeling and remote sensing of aerosols. I lead the NASA GSFC Chemistry-Climate Modeling group and am a co-chair of the International Cooperative for Atmospheric Prediction (ICAP). I have participated on the science teams and as a forecaster and flight planner in a number of NASA airborne missions including: SOLVE, CRYSTAL-FACE, CR-AVE, TC4, ARCTAS, GloPac, HS3, FIREX-AQ, and CPEX-CV. I have been a PI of NASA MAP, ACMAP, Aura, and New Investigator Progfram awarded proposals, and have led development of new instrument and measurement concepts under NASA GSFC internal IRAD and SIF funding. I have mentored over a dozen graduate students and post doctoral researchers, including a number of NASA Postdoctoral Program fellows and graduate student fellowship recipients.