This award will support collaborative research between US and French scientists on the topic of the air-snow transfer function in Greenland. The participants are: Drs. Jean- Luc Jaffrezo, Cliff Davidson and Jack Dibb, Carnegie Mellon University, and Dr. Michel Legrand, Laboratoire de Glaciologie et Geophysique de l'Environment, St. Martin d'Here, France. The US (GISP II) and European (GRIP) deep drilling projects involve acquisition of two deep cores to bedrock from the Summit region of Greenland over the next two years. The cores will provide a detailed record of about 200,000 years, yielding information on the earth's geologic history, climate change and variations in the chemical composition of atmospheric constituents. One important component of the GISP II and GRIP projects is a program in atmospheric sciences, which is designed to help relate the ice core data to atmospheric conditions in previous times. There are three objectives to this program: 1) Source regions and atmospheric pathways for the chemical constituents reaching the Summit will be identified; 2) Incorporation of these species into precipitation at the Summit will be investigated, in order to determine the mechanisms and rates of deposition during snowstorms; and 3) Changes in the chemical composition of the icesheet will be quantified. These objectives will be achieved by a multicomponent program that incorporates field work, laboratory analyses, and computer modelling. This award will support collaboration between US and French researchers for the purpose of carrying out laboratory work, data interpretation and joint publications related to the above projects. This effort will benefit from the complementary expertise of the US and French teams in the geochemistry of gases and aerosols, of tracers of natural and anthropogenic emissions and of transport and deposition mechanisms. The results of this research are expected to improve greatly the ability of the scientific community to retrieve information from deep ice.
