On the shoulders of giants

Research Notes

The shrinking Arctic ice cover is one of the most detectable signs of climate change, easy to observe by satellite. Detecting sea ice thickness is much harder. If the remaining ice is thin, it can disappear very fast. How much of this precious white substance that keeps our planet cool is still there?

By: Polona Itkin // UiT The Arctic University of Norway, Dmitry Divine and Adam Steer // Norwegian Polar Institute and Rolf-Ole Rydeng Jenssen // NORCE
Snow dunes/sastrugi on sea ice. Photo: Adam Steer / Norwegian Polar Institute

One of the biggest obstacles in our efforts to solve this puzzle is snow on sea ice. Snow is one of the best insulators and reflectors found in nature, but it is difficult to observe via satellite. The uncertainties of the satellite retrievals are high, but new methods are under development and new research missions are being organised. In this critical moment, sea ice researchers aspire to provide the best ground observations of Arctic sea ice cover – observations that can be used for calibration and validation of airborne and satellite observations.

Field training in Ramfjorden, calibration of multi frequency electromagnetic sensor (GEM-2) for sea ice thickness measurement. Photo: Andrea Schneider / UiT The Arctic University of Norway

Sea ice and snow data are scarce and therefore every expedition’s data set is precious. Getting into the Arctic and collecting data remain as major logistic challenges. Combinations of data sets that span a long period and cover large enough areas are most suitable for comparison with the satellite data. It is therefore essential to collect the data in as consistent a way as possible. At the same time we should use advances in technology to collect better data.

Standing on know-how of Arctic expeditions since the age of Fritjof Nansen, Fram Centre sea ice scientists, along with their international colleagues, are adopting and improving the standardised method developed for MOSAiC and bring it also to the Nansen Legacy  expeditions.

GEM-2 in action on a Nansen Legacy expedition in spring 2021 in the northern Barents Sea. Photo: Polona Itkin / UiT The Arctic University of Norway

IceTEC was an incentive project of the Fram Centre in 2021 that helped organise joint field work training on fjord ice in Ramfjorden at Tromsø and kick-started development of a lightweight radar system for snow and ice observations from small off-the-shelf drones. This will hopefully facilitate future collection of detailed data that can be used together with satellite data to resolve some of the uncertainties surrounding snow cover on sea ice.