Abstract
Abstract. Estimating the long-term mass balance of the high-Arctic Svalbard archipelago is difficult due to the incomplete geodetic and direct glaciological measurements, both in space and time. To close these gaps, we use a coupled surface energy balance and snow pack model to analyse the mass changes of all Svalbard glaciers for the period 1957–2014. The model is forced by ERA-40 and ERA-Interim reanalysis data, downscaled to 1 km resolution. The model is validated using snow/firn temperature and density measurements, mass balance from stakes and ice cores, meteorological measurements, snow depths from radar profiles and remotely sensed surface albedo and skin temperatures. Overall model performance is good, but it varies regionally. Over the entire period the model yields a climatic mass balance of 8.2 cm w. e. yr−1, which corresponds to a mass input of 175 Gt. Climatic mass balance has a linear trend of −1.4 ± 0.4 cm w. e. yr−2 with a shift from a positive to a negative regime around 1980. Modelled mass balance exhibits large interannual variability, which is controlled by summer temperatures and further amplified by the albedo feedback. For the recent period 2004–2013 climatic mass balance was −21 cm w. e. yr−1, and accounting for frontal ablation estimated by Błaszczyk et al.(2009) yields a total Svalbard mass balance of −39 cm w. e. yr−1 for this 10-year period. In terms of eustatic sea level, this corresponds to a rise of 0.037 mm yr−1. Refreezing of water in snow and firn is substantial at 22 cm w. e. yr−1 or 26 % of total annual accumulation. However, as warming leads to reduced firn area over the period, refreezing decreases both absolutely and relative to the total accumulation. Negative mass balance and elevated equilibrium line altitudes (ELAs) resulted in massive reduction of the thick (> 2 m) firn extent and an increase in the superimposed ice, thin (< 2 m) firn and bare ice extents. Atmospheric warming also leads to a marked change in the thermal regime, with cooling of the glacier mid-elevation and warming in the ablation zone and upper firn areas. On the long-term, by removing the thermal barrier, this warming has implications for the vertical transfer of surface meltwater through the glacier and down to the base, influencing basal hydrology, sliding and thereby overall glacier motion.
Highlights
Glaciers are widely acknowledged as good indicators of climate change (e.g. AMAP, 2011), but the relationship between atmosphere, surface energy balance and glacier mass balance is complex
For the recent period 2004–2013 climatic mass balance was −21 cm w.e. yr−1, and accounting for frontal ablation estimated by Błaszczyk et al (2009) yields a total Svalbard mass balance of −39 cm w.e. yr−1 for this 10-year period
The modelled mean annual Bclim averaged over the entire domain for the period 1957 to 2014 is positive (8.2 cm w.e. yr−1), which corresponds to a mass gain of 3.1 Gt yr−1 using the current glacier mask of each year
Summary
Glaciers are widely acknowledged as good indicators of climate change (e.g. AMAP, 2011), but the relationship between atmosphere, surface energy balance and glacier mass balance is complex. Glaciers are widely acknowledged as good indicators of climate change AMAP, 2011), but the relationship between atmosphere, surface energy balance and glacier mass balance is complex. Glaciers and ice caps are currently among the major contributors to current sea level rise (Church et al, 2011), despite their relative small volume compared to the ice sheets of Greenland and Antarctica, and are assumed to be important throughout the 21st century (Meier et al, 2007). The high-Arctic archipelago Svalbard has an estimated total eustatic sea level rise potential of 17–26 mm
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
