Ice Surface Velocity in the Eastern Arctic from Historical Satellite SAR Data

Abstract. Knowledge on ice surface velocity of glaciers and ice caps contributes to a better understanding of a wide range of processes related to glacier dynamics, mass change and response to climate. Based on the recent release of historical SAR data from various space agencies we compiled nearly complete mosaics of winter ice surface velocities for the 1990’s over the Eastern Arctic (Novaya Zemlya, Franz-Josef-Land, Severnaya Zemlya and Svalbard), a region with sparse optical velocity records from these years. We mainly applied offset-tracking to JERS-1 SAR data and filled data gaps using SAR interferometry and offset-tracking from ERS-1/2 SAR data. We studied the long-term variability of winter ice surface velocity by comparing our 1990’s results to 2008–2011 velocity maps from ALOS-1 PALSAR-1 and 2020–2021 maps from Sentinel-1. A general increase of winter velocities from the 1990’s to present along with a retreat of glacier fronts is obsverved. Exceptions to this general pattern are surges, which are widespread over Svalbard but rarely found in the other three regions. The dense time series of ice surface velocity from Sentinel-1 since 2015 were also considered to infer the representativeness of winter data with respect to mean annual values. We found that for non-surging glaciers short-term seasonal fluctuations are relatively small and winter ice surface velocities are a good representative of mean annual velocities with an underestimation of less than 10 %. Together with consistent datasets of glacier ice thickness and terminus position, the ice surface velocities in the Eastern Arctic provide the basis to quantify the regional decadal average calving flux during the 1990’s. The ice surface velocity data set for the 1990’s over the Eastern Arctic from satellite SAR data can be downloaded from https://doi.pangaea.de/10.1594/PANGAEA.938381 (Strozzi et. al., 2021).