The Greenland Crest as a Test laboratory for Iceshield-Air Interaction Processes

Automatic weather station (AWS) units were installed around the Greenland Crest in June 1992. Four AWS sites were approximately 100 km from and to the east, south, west, and north from the Greenland Crest. Two sites were located near the center of the outer array. The AWS unites measure wind speed and direction and air temperature at a nominal height of 3 meters. Air pressure is measured at the electronics enclosure at about 2 m above the surface at the time of nstallation. Three sites were equipped with acoustic depth gauges to measure snow accumulation. During June, July, August and September 1994 everything was working. Divergence and vorticity from three and four site arrays were calculated at hourly intervals using wind speed and direction observations at 10 minute intervals. Acoustic depth gauge measurements were made at one hour intervals. August and September 1994 generally had positive divergence and anticyclonic vorticity. The one significant exception occurred during the third week of September 1994 when cyclonic vorticity and convergence occurred for portion of two days in a row, 23 and 24 September 1994. On day 23 there was precipitation at two sites when the divergence and vorticity were negative. On day 24 the snow was removed by the wind and transported towards the Greenland Crest. The poster will illustrate the time series of the changes that occurred and the interrelationships of divergence, vorticity, snow accumulation and snow transport by the surface stress.