Remote sensing of North Greenland glaciers from the 1970s to present

The Arctic is one of the fastest-warming regions in a rapidly warming world. Arctic glaciers are an important contributor to sea level rise, and their increased mass change and retreat has impacts ranging from local-scale ecosystems to regional-scale changes in ocean chemistry and circulation. Longer-term observations, especially of elevation and volume changes, are key for understanding and constraining predictions of future sea level change and other environmental impacts.

Over recent decades, peripheral glaciers in Greenland north of 79° latitude showed fairly steady rates of negative mass balance and small rates of area change, in spite of strongly increased regional warming. In this study, we combine a broad range of remotely sensed imagery and datasets to observe decade-scale changes to peripheral glaciers in the North of Greenland over a 50 year time period. We use historical aerial and declassified satellite imagery as well as Landsat and Sentinel-2 scenes to map glacier area across each decade through a semi-automated approach. To map accumulation area ratio (AAR) for each time period, we apply an albedo threshold approach that has been used to differentiate between snow and bare ice in other regions. Finally, we derive elevation changes using a combinaton of historic aerial and satellite-derived digital elevation models (DEMs) from the 1970s, the ArcticDEM, and ASTER and SPOT-5 derived DEMs to observe elevation and volume changes over the same time period. With the benefit of multiple glacier inventories, we also evaluate the impact of deriving geodetic mass balances from glacier outlines at different points in time.