Freshwater input to the Arctic fjord Hornsund (Svalbard)

Abstract

Glaciers draining to the Hornsund basin (southern Spitsbergen, Svalbard) have experienced a significant retreat and mass volume loss over the last decades, increasing the input of freshwater into the fjord. An increase in freshwater input can influence fjord hydrology, hydrodynamics, sediment flux and biota, especially in a changing climate. Here, we describe the sources of freshwater supply to the fjord based on glaciological and meteorological data from the period 2006 to 2015. The average freshwater input from land to the Hornsund bay is calculated as 2517 ± 82 Mt a −1 , with main contributions from glacier meltwater runoff (986 Mt a −1 ; 39%) and frontal ablation of tidewater glaciers (634 Mt a −1 ; 25%). Tidewater glaciers in Hornsund lose ca. 40% of their mass by frontal ablation. The terminus retreat component accounts for ca. 30% of the mass loss by frontal ablation, but it can vary between 17% and 44% depending on oceanological, meteorological and geomorphological factors. The contribution of the total precipitation over land excluding winter snowfall (520 Mt a −1), total precipitation over the fjord area (180 Mt a −1) and melting of the snow cover over unglaciated areas (197 Mt a −1) to the total freshwater input appear to be small: 21%, 7% and 8%, respectively.

Quality Assessment and Glaciological Applications of Digital Elevation Models Derived from Space-Borne and Aerial Images over Two Tidewater Glaciers of Southern Spitsbergen

“…In the end, we estimated geometry changes of Hansbreen and Hornbreen and compared the geodetic and climatic mass balance of Hansbreen. The main reason for selecting these glaciers was that they were the subject of ongoing field programs (e.g., [24,25,[27][28][29][30] and World Glacier Monitoring Service-https://wgms.ch/). The proximity of the Polish Polar Station Hornsund enabled wide-ranging field studies (mass balance, GPR and GPS measurements) to be carried out, which could be further used to investigate the accuracy and application of DEMs.…”

“…The volume of ice loss by frontal recession (q t ) was estimated from the bathymetry from Błaszczyk et al [29], the glacier surface elevation at the beginning of the period and the area of recession from the adequate orthoimages. The component of the retreated front area was converted to mass using ice density ρ = 900 kg m −3 .…”

“…where B s f c is surface mass balance calculated as linear regression of elevation and net mass balance from WGMS data and A f is total frontal ablation defined as sum of glacier retreat (q t ) and glacier ice flux (q f g ) [29,52]. H is the ice thickness along the flux gate, w is the width of the flux gate, and v is the velocity across the flux gate.…”

“…The estimation of q t is described in Section 3.6. The ice flux through a flux gate near the calving front (q fg ) used in this study was estimated by Błaszczyk et al [29] based on the TerraSAR-X velocity data from 2012. The error was estimated using the total differential function, as follows:…”

Role of discrete water recharge from supraglacial drainage systems in modeling patterns of subglacial conduits in Svalbard glaciers

“…Spatial distribution in the surface ablation model was generated based on the summer mass balance data provided by the World Glacier Monitoring Service (WGMS), relying on the mass balance stake network present on both glaciers ( Fig. 1) (Błaszczyk et al, 2019). WGMS provides data on accumulation and ablation points on the glaciers (WGMS, 2017).…”