Earth and Planetary Science

Professor Cohen's group addresses the connection between molecular reactions and regional or global scale atmospheric phenomena: What chemical reactions control whether ozone is locally produced or consumed in the urban and remote troposphere? How do these regional processes affect the oxidative capacity of the atmosphere on a global scale? What are the primary reactions controlling the rate of photochemical removal of ozone in the stratosphere? What are the natural and human induced variations in the concentrations of the free radicals that are rate limiting in these reactions? What is the molecular event during evaporation of water? These questions guide an interdisciplinary chemical/geophysical approach to exploring the structure and dynamics of the earth-ocean-atmosphere system. Cohen’s work emphasizes development of new technologies to obtain detailed observations of atmospheric composition and to validate and interpret large-scale records obtained from space-borne instruments.

A principal research activity of Inez Fung is the carbon dioxide cycle. Fung’s lab uses details of the atmospheric CO2 distribution (e.g. the difference in hemispheric loading, the changes in the seasonal amplitude over time), together with atmospheric transport models to deduce the location of the carbon sink. Fung hypothesizes that the terrestrial biosphere of the northern hemisphere may be as important as the oceans as a repository for anthropogenic CO2. Another research focus is the dust cycle. Fine dust particles lofted from arid surfaces are transported long distances. While airborne, they reflect sunlight, but may, depending on their sizes and composition, absorb terrestrial radiation. When deposited to the surface oceans, the iron in the dust may be the critical limiting micronutrient for marine productivity in some ocean regions. To tackle this problem, she is combining mineralogic information about soil particles, satellite and in-situ observations, atmospheric circulation models and ocean biology models to gain an appreciation of the many roles of dust.