Abstract
Snow is the dominant form of precipitation and the main cryospheric feature of the High Arctic (HA) covering its land, sea, lake and river ice surfaces for a large part of the year. The snow cover in the HA is involved in climate feedbacks that influence the global climate system, and greatly impacts the hydrology and the ecosystems of the coldest biomes of the Northern Hemisphere. The ongoing global warming trend and its polar amplification is threatening the long-term stability of the snow cover in the HA. This study presents an extensive review of the literature on observed and projected snow cover conditions in the High Arctic region. Several key snow cover metrics were reviewed, including snowfall, snow cover duration (SCD), snow cover extent (SCE), snow depth (SD), and snow water equivalent (SWE) since 1930 based on in situ, remote sensing and simulations results. Changes in snow metrics were reviewed and outlined from the continental to the local scale. The reviewed snow metrics displayed different sensitivities to past and projected changes in precipitation and air temperature. Despite the overall increase in snowfall, both observed from historical data and projected into the future, some snow cover metrics displayed consistent decreasing trends, with SCE and SCD showing the most widespread and steady decreases over the last century in the HA, particularly in the spring and summer seasons. However, snow depth and, in some regions SWE, have mostly increased; nevertheless, both SD and SWE are projected to decrease by 2030. By the end of the century, the extent of Arctic spring snow cover will be considerably less than today (10–35%). Model simulations project higher winter snowfall, higher or lower maximum snow depth depending on regions, and a shortened snow season by the end of the century. The spatial pattern of snow metrics trends for both historical and projected climates exhibit noticeable asymmetry among the different HA sectors, with the largest observed and anticipated changes occurring over the Canadian HA.
Highlights
The High Arctic (HA) terrestrial ecosystem is a remote and extremely cold biome often referred to as a polar desert [1]
Young et al [26] studied the variability of snow cover duration (SCD) in Bathurst and Cornwallis Island in the Canadian HA using a combination of in situ snow survey and snowmelt measurements, as well landscape-scale snow cover observations from remote sensing. They found no reduction in SCD at the point scale due to insufficient data, but they observed a shallower snowpack around ponds and plateau sites while they found deeper snow in incised valleys
Observational evidence from in situ and satellite data demonstrate that the snow cover has been modified across the Arctic [8,10,76] as a result of warming air temperatures during the last decades and is expected to continue doing so into the present century according to the Intergovernmental Panel on Climate Change (IPCC) six assessment report on climate change [66]
Summary
The High Arctic (HA) terrestrial ecosystem is a remote and extremely cold biome often referred to as a polar desert [1]. The snow cover is responsible for several interactions and feedbacks in the HA that influence the climate, hydrology and ecology [9,10] of the region, due to its effects on the surface energy balance. Trends in historical climate have affected key characteristics snow cover, such as its amount, timing and duration (e.g., [16,17,18]) These changing charof snow cover, such as its amount, timing and (e.g., consequences [16,17,18]). The present review is the first to provide an integrative review of both historical and projected changes in snow cover conditions for the High Arctic, a climatologically and projected changes in snow cover conditions for the High Arctic, a climatologically and and ecologically unique region that comprises the polar desert biome.
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