Increased Ice Thinning over Svalbard Measured by ICESat/ICESat-2 Laser Altimetry

Lukas Sochor,Matthias H Braun,Thorsten Seehaus

doi:10.3390/rs13112089

Abstract

A decade-long pronounced increase in temperatures in the Arctic, especially in the Barents Sea region, resulted in a global warming hotspot over Svalbard. Associated changes in the cryosphere are the consequence and lead to a demand for monitoring of the glacier changes. This study uses spaceborne laser altimetry data from the ICESat and ICESat-2 missions to obtain ice elevation and mass change rates between 2003–2008 and 2019. Elevation changes are derived at orbit crossover locations throughout the study area, and regional volume and mass changes are estimated using a hypsometric approach. A Svalbard-wide annual elevation change rate of −0.30 ± 0.15 m yr−1 was found, which corresponds to a mass loss rate of −12.40 ± 4.28 Gt yr−1. Compared to the ICESat period (2003–2009), thinning has increased over most regions, including the highest negative rates along the west coast and areas bordering the Barents Sea. The overall negative regime is expected to be linked to Arctic warming in the last decades and associated changes in glacier climatic mass balance. Further, observed increased thinning rates and pronounced changes at the eastern side of Svalbard since the ICESat period are found to correlate with atmospheric and oceanic warming in the respective regions.

Highlights

The estimated Svalbard-wide dh/dt value is −0.30 ± 0.15 m yr−1, including highest rates at South Spitsbergen with −0.80 ± 0.18 m yr−1 and lowest elevation change at Austfonna and northeast Spitsbergen with −0.07 ± 0.09 m yr−1 and
Hotspots of thinning are found at the margins of the archipelago and at some marine-terminating and surging glaciers
Findings of the ICESat/ICESat-2 comparison mostly agree with recent Svalbard-wide CryoSat-2 measurements in 2011–2017 [19] and likewise show increased elevation decrease rates in almost all regions, as well as a spread of pronounced thinning from the west coast to areas bordering the Barents-Sea compared to intra-ICESat acquisitions in 2003–2008 [20]

Summary

Introduction

Academic Editors: Tomislav Bašić and Marijan Grgić. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Several satellite-mounted laser and radar sensors have been used to continuously measure surface elevation change of glacier and ice caps in the last decades (e.g., [1,2,3,4,5]). While radar systems typically exhibit a large footprint of several meters to kilometers and can penetrate into ice, snow, and firn (e.g., [6]), the advantages of laser altimetry lie in a small footprint of cm to meters and in the measurement of precise surface heights with little subsurface penetration. Glacier topography investigations with laser altimeters were initially mainly conducted through aircraft campaigns (e.g., [7,8])

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Conclusion