This June, Greenland Guidance joined the annual maintenance of weather stations high up on the Greenland ice sheet. One major difference with instrument maintenance closer to the ice sheet margin is that equipment in the interior of the ice sheet gradually gets buried by snow. In the higher parts melt is rare, and more snow accumulates in a year than that it melts. At low elevations summer melting is abundant, ablating winter snow and several meters of the underlying ice. Ice dynamics take care of the ice mass transfer from high to low elevations – otherwise the ice sheet would get taller and steeper each year.
A downside to working in the accumulation area is that one needs to shovel snow pits of 3 m deep to retrieve buried equipment, which is particularly challenging given the thin air at 2-3 km above sea level. Also travel distances are larger between the science site and the airport where you start the day, meaning that there is a larger chance of running into adverse weather delaying the operation. On the other hand the work can be done by a fixed-wing aircraft equipped with skis, as opposed to the helicopters required to land in low-elevation, uneven, or even crevassed terrain. These airplanes don’t worry as much about weather conditions as helicopters do. And they can carry a lot of equipment.
Not hampered by cloudy or windy conditions, we visited five measurement sites of the Greenland Climate Network (GC-Net) by Kenn Borek Air Twin Otter in six days. This year is the first year that GC-Net maintenance is done by the Geological Survey of Denmark and Greenland (GEUS). The network recently changed hands. The GC-Net got established by the Cooperative Institute for Research in Environmental Sciences (CIRES) in Boulder (US) in the 1990s and has since delivered large amounts of important climate data, contributing to many scientific studies and climate reports. Professor Konrad Steffen was a central person in all this, pushing the benefit of these measurements to climate science to great heights.