Martin Wahlen

One: Reconstruction of paleoatmosperes from ice core records in Greenland and Antarctica; main emphasis is to reconstruct atmospheric CO2 and d13CO2. Two: Global biogeochemical cycles of radiatively important green house gases; biosphere-atmosphere interactions. Three: Stable isotopes in atmospheric CO2 (d13 CO2 and d18CO2) to arrive at an improved global carbon cycle budget (in collaboration with C. D. Keeling). Four: Stable isotope process-oriented studies to determine the role of 18O in atmospheric CO2. Five: Stable isotopes of Cl and Br in aerosols to determine if Cl and Br radicals are produced in the troposphere. Six: Stable isotope investigations of CO2, CH4, 85 Kr, and N2O in the stratosphere to determine the troposphere/stratosphere air exchange rate.