Air-snow exchange investigations at Summit, Greenland: An overview

The Greenland Ice Sheet Project 2 (GISP2) and Greenland Ice Core Project (GRIP) deep drilling programs at Summit, Greenland included support (both logistical and scientific) of extensive investigation of atmospheric transport and air-snow exchange processes of gases and particles relevant to the interpretation of the ice-core records. Much of the sampling for the air-snow exchange investigations was conducted at a unique 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 expertise and analytical capabilities of the 20-plus investigators participating in these studies has provided important insight into the meteorological, physical, and chemical processes which interact to determine the composition of snow and firn at Summit. Evolving understanding of this system will allow improved reconstruction of the composition of the atmosphere over Greenland in the past from the detailed Summit ice-core records. This Paper provides an overview of air-snow exchange investigations at Summit, including their development through the course of the drilling programs (1989-1993), significant findings related to both air-snow exchange issues and the present state of the Arctic free troposphere, as well as the major outstanding questions which are being addressed in ongoing experiments at Summit.