Recent retreat of major outlet glaciers on Novaya Zemlya, Russian Arctic, influenced by fjord geometry and sea-ice conditions

Substantial ice loss has occurred in the Russian High Arctic during the past decade, predominantly on Novaya Zemlya, yet the region has been studied relatively little. Consequently, the factors forcing mass loss and the relative contribution of ice dynamics versus surface melt are poorly understood. Here we evaluate the influence of atmospheric/oceanic forcing and variations in fjord width on the behaviour of 38 glaciers on the northern ice cap, Novaya Zemlya. We compare retreat rates on landversus marine-terminating outlets and on the Kara versus Barents Sea coasts. Between 1992 and 2010, 90% of the study glaciers retreated and retreat rates were an order of magnitude higher for marine-terminating outlets (52.1 m a–1) than for land-terminating glaciers (4.8 m a–1). We identify a post-2000 acceleration in marine-terminating glacier retreat, which corresponded closely to changes in sea-ice concentrations. Retreat rates were higher on the Barents Sea coast, which we partly attribute to lower sea-ice concentrations, but varied dramatically between individual glaciers. We use empirical data to categorize changes in along-flow fjord width, and demonstrate a significant relationship between fjord width variability and retreat rate. Results suggest that variations in fjord width exert a major influence on glacier retreat. DOI: https://doi.org/10.3189/2014JoG13J122 Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-97195 Published Version Originally published at: Carr, J Rachel; Stokes, Chris R; Vieli, Andreas (2014). Recent retreat of major outlet glaciers on Novaya Zemlya, Russian Arctic, influenced by fjord geometry and sea-ice conditions. Journal of Glaciology, 60(219):155-170. DOI: https://doi.org/10.3189/2014JoG13J122 Recent retreat of major outlet glaciers on Novaya Zemlya, Russian Arctic, influenced by fjord geometry and sea-ice conditions J. Rachel CARR, Chris STOKES, Andreas VIELI Department of Geography, Durham University, Durham, UK E-mail: [email protected] Department of Geography, University of Zürich, Zürich, Switzerland ABSTRACT. Substantial ice loss has occurred in the Russian High Arctic during the past decade, Substantial ice loss has occurred in the Russian High Arctic during the past decade, predominantly on Novaya Zemlya, yet the region has been studied relatively little. Consequently, the factors forcing mass loss and the relative contribution of ice dynamics versus surface melt are poorly understood. Here we evaluate the influence of atmospheric/oceanic forcing and variations in fjord width on the behaviour of 38 glaciers on the northern ice cap, Novaya Zemlya. We compare retreat rates on landversus marine-terminating outlets and on the Kara versus Barents Sea coasts. Between 1992 and 2010, 90% of the study glaciers retreated and retreat rates were an order of magnitude higher for marine-terminating outlets (52.1ma) than for land-terminating glaciers (4.8ma). We identify a post-2000 acceleration in marine-terminating glacier retreat, which corresponded closely to changes in sea-ice concentrations. Retreat rates were higher on the Barents Sea coast, which we partly attribute to lower sea-ice concentrations, but varied dramatically between individual glaciers. We use empirical data to categorize changes in along-flow fjord width, and demonstrate a significant relationship between fjord width variability and retreat rate. Results suggest that variations in fjord width exert a major influence on glacier retreat.