This is one of four coordinated projects that will make use of the camp facilities established on the ice sheet in the interior of Greenland as part of the GISP-2 ice core drilling effort, in order to investigate how atmospheric trace elements are deposited on the ice and what kind of changes they undergo as they are being incorporated into the ice. An understanding of such processes is necessary in order to properly interpret the proxy climate data that can be recovered from ice cores. While significant progress has been made recently in extracting and analyzing ice cores, progress in understanding the air to snow transfer process for reactive chemical species has lagged behind. The goal of this project is to determine the atmosphere to snow transfer function for chemical species whose deposition is reversible, i.e. ones that can move from the snow back into the atmosphere to be removed or redeposited elsewhere. The two species to be investigated are hydrogen peroxide and formaldehyde. Based on measurements of their concentration in the free atmosphere, in the air within the snow, as well as in snow, and ice, a transfer model will be developed. Concurrent laboratory studies will be done to determine and constrain model parameters such as chemical equilibrium coefficients and mass transfer coefficients. The model will be generalized to other reactive species, such as nitric acid, and organic acids.
