CURRENT RESEARCH

Our goal is to better understand the chemical composition of the atmosphere, its perturbation by human activity, and the implications for life on Earth. We use advanced global models of atmospheric composition to interpret observations from satellites, aircraft, ground networks, and other sources. We view our models as part of an integrated observing system bridging the information from different data sets to increase our understanding of atmospheric composition in a way that serves both fundamental knowledge and the need to address pressing environmental issues.

GLOBAL MODELS. A central tool in our research is the GEOS-Chem global 3-D model of atmospheric composition, developed by a large grass-roots research community at Harvard and elsewhere and applied to a very wide range of problems. See the GEOS-Chem web site for more details. We also work with the NASA/GISS general circulation model for simulations of climate change, including coupling with GEOS-Chem for study of chemistry-climate interactions and of past and future atmospheres.	AIRCRAFT MISSIONS. Aircraft provide a critical sampling platform for atmospheric chemistry. They enable detailed chemical characterization of atmospheric composition from the surface to the stratosphere and over the scale of the globle. We have been engaged in a large number of aircraft missions over the past 20 years in different regions of the world. We are presently involved in the NASA ARCTAS mission to the Arctic and the NSF HIPPO pole-to-pole mission. Our role in these missions includes overall mission design, flight planning, forecasting, and post-mission data analysis.	SATELLITE MISSIONS. Satellite observations are revolutionizing atmospheric chemistry research by providing global and continuous data sets of atmospheric composition. These data sets require advanced models for interpretation and we are in the thick of it. We serve on the Science Teams of the TES, MOPITT, and OCO instruments, and are also engaged in the analysis of data from MODIS, MISR, GOME, SCIAMACHY, and OMI. Our activities involve direct retrievals of satellite spectra using radiative transfer models, chemical data assimilation, inverse model analyses,and other data interpretation.