Two decades of glaciological investigations in South and Central Greenland

Abstract

This report is the first of two papers summarizing the glaciologal observations made on the southern and central parts of the Greenland Ice Sheet during two field campaigns conducted during the 1980s by scientists at The Ohio State University's Byrd Polar Research Center. Three large clusters of survey stations, as well as a strain grid leading to the Dye‐3 borehole, were deployed and surveyed in 1980, and resurveyed the next summer (1981). In 1987 and 1989, similar surveys were conducted in the Summit region as part of the GISP2 site selection. The primary objectives of these field campaigns were to measure absolute surface velocities and to obtain 20–30 year average accumulation rates from shallow firn cores. Velocities were determined using the U.S. Navy Navigational Satellite System, otherwise known as the TRANSIT system. To obtain accurate positions for survey stations on the ice sheet, the short‐arc method was used, in which satellite tracking stations at two stationary coastal stations were operated simultaneously with tracking stations on the ice sheet. Positions of the ice‐sheet tracking stations are calculated relative to the coastal stations and the fixed coordinates of these reference stations are determined from point positioning using the precise orbit parameters. Repeating this procedure at a later date allows ice sheet motion to be determined.