Flying expeditions supplements satellite images
Measurements taken from aircraft ensure improved monitoring of the changes in inland and sea ice. However, this method will soon be supplemented by the use of large drones with the capacity to deal with the tough conditions.
DTU Space has recently sent a team of researchers to Greenland, where they took on the challenging autumn weather to fly back and forth across the country, measuring the properties of the inland ice. It is the first time that such flights have been performed since 1998 and Henriette Skourup, Researcher, took part in 15 expeditions.
“It may seem strange, because we have access to a constant stream of satellite data. However, it is difficult to allow for how deeply the satellite radar signals penetrate the top layers of snow on the inland ice, especially given that the snow cover on the ice varies during the year. That’s why we collect supplementary information from the fly-overs,” relates Henriette Skourup, who was in charge of the autumn activities.
The aircraft is fitted with the same laser and radar instruments as the satellites, and by comparing data from the fly-overs and incorporating knowledge from samples bored from the ice itself, researchers can correct the satellite data and present a more accurate picture of the extent of climate change. This is knowledge that is sure to become increasingly relevant in the context of the rapid changes currently taking place in the Arctic.
“It’s the first time I’ve been to Greenland this late in the year. We arrived at the same time as winter, which meant that the days quickly became shorter, robbing us of hours of daylight. What is more, the weather conditions at this time of year can be so bad that we can’t fly at all, but fortunately, we were only grounded for two days,” says Henriette Skourup.
The collection of data by flying over the inland ice and the sea ice around Greenland takes place at such a low altitude that is is possible to see the differences in height of the ice and spot fissures in the ice floes, for example.
The data are subsequently analysed and compared with information gathered from flights in the spring—when the snow coverage after the winter months is deepest—to produce recommendations. These recommendations are used to correct satellite measurements of the ice on and around Greenland in relation to the different seasons and snow volumes. They are published on the European Space Agency’s (ESA) website together with data from the ESA satellite Cryosat, so they can be used by researchers and other organizations around the world to keep track of changes in how the inland ice is melting.
Henriette expects the number of flights to be cut in the future.
“DTU Space is working to develop large drones with the capacity to handle the tough climatic conditions on Greenland. The first of these should be ready for test flights as early as 2017, so monitoring from aircraft could be phased out completely in the long term.”
source: Technical University of Denmark