AIR-SNOW EXCHANGE INVESTIGATIONS AT SUMMIT, GREENLAND - AN OVERVIEW

The Greenland Ice Sheet Project 2 (GISP2) and Greenland Ice Core Proje ct (GRIP) deep drilling programs at Summit, Greenland included support (both logistical and scientific) of extensive investigation of atmosp heric transport and air-snow exchange processes of gases and particles relevant to the interpretation of the ice-core records. Much of the s ampling for the air-snow exchange investigations was conducted at a un ique solar-powered camp 30 km southwest of the GISP2 drill camp (even further from the GRIP camp) and was characterized by a high degree of international collaboration and cooperation. The wide range of experti se and analytical capabilities of the 20-plus investigators participat ing in these studies has provided important insight into the meteorolo gical, physical, and chemical processes which interact to determine th e composition of snow and firn at Summit. Evolving understanding of th is system will allow improved reconstruction of the composition of the atmosphere over Greenland in the past from the detailed Summit ice-co re records. This Paper provides an overview of air-snow exchange inves tigations at Summit, including their development through the course of the drilling programs (1989-1993), significant findings related to bo th air-snow exchange issues and the present state of the Arctic free t roposphere, as well as the major outstanding questions which are being addressed in ongoing experiments at Summit.