9321420 Albert The proposed project is a field study of the physical processes that affect the manner in which atmospheric constituents are incorporated into polar snow and firn at the surface of the Greenland ice sheet. These processes are an important component in reconstructing the characteristics of paleoatmospheres from the observation of inclusions in deep ice cores, and consist of the direct transport by the flow of air within the snow (advection), the molecular scale dispersion (diffusion), and the effects of solar radiation penetrating into the snow. The air-to-snow transfer of atmospheric constituents is filtered and potentially altered by such processes. The objectives are to define the magnitude and extent in space and time of these transfer processes, and to develop a process-level understanding and a capability to model these processes. Field studies will be conducted in central Greenland in the summer of 1994 to determine the spatial and temporal variability of key parameters, and to observe boundary conditions needed to constrain the model. An existing multidimensional numerical model will be extended and verified to simulate the advection, diffusion, and radiation transmission/absorption processes. ***
