Snow Depth on Sea Ice and on Land in the Canadian Arctic from Long-Term Observations

Intra-annual and decadal observations of snow depth on sea ice and on terrestrial land are examined within the Canadian Arctic. In situ snow depth measurements at 11 study sites spanning 1955-2019 form the basis of the analysis. Ice chart data acquired via the Canadian Ice Service are used to establish sea ice break-up and freeze-up dates and assess their impact on snow depth evolution. We find that on-ice and on-land snow accumulation in autumn differ due to the lag between the freeze-up and the first snow of the season. Once sea ice consolidates, on-ice and on-land snow depth become positively correlated in winter (p < 0.05). The mean seasonal rate of snow accumulation on sea ice from September to April is 3.2 +/- 0.6 cm month(-1) across the Canadian Arctic. Snow depth on terrestrial land is generally higher than on sea ice in the southern Canadian Arctic by up to 20-30 cm; but snow depth on sea ice tends to exceed that on land in the northern Canadian Arctic from winter to spring. Four sites (Eureka, Resolute, Cambridge Bay and Hall Beach) with continuous long-term records are selected for interannual analysis. Decadal trends in on-ice snow depth are mostly negative from autumn to spring. Autumn and spring snowfall have increased at three of the four sites. The Canadian Arctic experiences warming on a decadal scale, especially in autumn, by 0.5 to 0.8 degrees C decade(-1). Sea ice freeze-up is delayed by up to 2.5 days decade(-1) in the southern Canadian Arctic, whereas break-up occurs earlier by about 3 days decade(-1) in the northern Canadian Arctic.