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Abstract:
The mass balance of coastal Antarctica is significantly affected by warming in low-elevation areas. Summer melting in Antarctica can be a major concern in the warming climate scenario, but very few records exist for the coastal region. We present a 250-year ice core record of snow accumulation and summertime melting history from an ice core drilled at the summit of the Djupranen Ice Rise in coastal Dronning Maud Land, East Antarctica. Water-stable isotopes, visual stratigraphy, and major ion profiles were used to establish chronologies constrained by non-sea salt sulphate and tritium anomaly records. The melt index is calculated as the water-equivalent ratio of all melt layers in a year to total annual accumulation. The yearly average accumulation rate is 0.32 ± 0.14 m w.e. a-1, while the yearly mean melt rate is 1 ± 1.25 %. The ice core record shows a significant decrease in snow accumulation rates in recent decades. Accumulation rates show high variability, with a significant decline since the 1980s. Annual melt was surprisingly higher in the pre-industrial era (before 1850 CE), averaging 1.3 % compared to 0.9 % in the present. We observed melting events in 184 out of 248 years, with the lowest melting period being 1796–1809. There is no correlation between ERA5 2m temperature and annual melt or δ18O. In contrast, the ERA5 total precipitation trend is the opposite of annual snow accumulation from the ice core, suggesting a complex mechanism affecting the region's seasonal melting and snow accumulation rates.
