Recent glacier change (1965 - 2021) and identification of surge-type glaciers on Severnaya Zemlya, Russian High Arctic

Abstract

Glaciers in the Russian High Arctic are rapidly losing mass due to strong atmospheric and oceanic warming of the Barents-Kara Sea region. However, most studies have concentrated on Novaya Zemlya, despite a 29% acceleration in mass loss on Severnaya Zemlya (SZ) in the past decade (2003-2009 to 2010-2017). Research on SZ has formerly been hindered by its inaccessibility and limited data availability, with long-term trends in glacier change largely unknown. Moreover, records of glacier change on SZ may be complicated by evidence of surging, rather than solely due to climatic perturbations. In this thesis, an assessment of recent glacier change (1965 to 2021) on SZ is presented, along with a new inventory of surge-type glaciers from a high-resolution digital elevation model (Arctic DEM), declassified spy-satellite photography (KH-7/9 Hexagon), and optical satellite imagery (Sentinel 2, ASTER & Landsat 8 & TM). A total of 190 glaciers were mapped at five dates and surveyed for glaciological and geomorphological criteria indicative of former or active surging (e.g., thrust-block moraines and looped medial moraines). The results show that the glacierised area reduced from 17,053 km² in 1965 to 16,275 in 2021 (-778 km²) and retreat rates accelerated post-1997. There is no evidence of summer air temperature warming on northern SZ, with most glacier retreat occurring in the south of SZ where land-terminating glaciers have retreated (some up to 30%), attributed to emerging summer air temperature warming trends. Further north, glacier retreat is attributed to rising ocean temperatures and strong annual atmospheric warming which has likely lengthened the melt season. Additionally, four glaciers are classified as surge-type, seven as likely and nine as possible, comprising 11% of SZ’s glaciers. These glaciers occupy larger basins and are more likely to be marine or lake terminating.