REMOTE SENSING OF RAPIDLY CHANGING SNOW REGIMES IN NORTHERN SCANDINAVIA

摘要: The Arctic climate is warming at twice the global rate, and winter temperatures are increasing even faster. Snow is one of the most important determinants of biogeosystem functions in arctic and alpine tundra, where snow dominates the landscape for most of the year. Snow has a strong regulatory effect on local hydrology, soil temperature, permafrost, carbon and nutrient cycling, primary production and the distribution of vegetation types (Bokhorst et al. 2016). Snow cover thickness and duration are sensitive indicators of climate change (Callaghan et al. 2011), but snow data provided by climate stations are biased towards flat areas and close proximity to human settlements. Therefore, a wide range of snow accumulation regimes, especially in the sparsely populated arctic tundra, are not represented in climate station data. Remote sensing provides repeated information on the cryosphere at multiple scales of space and time. However, most snow-related remote sensing studies have used satellite instruments with a very coarse resolution (1–35 km), which is not suitable for detecting the distinct local heterogeneity of snow accumulation.Here, we present results on recent (from 1984 to 2016) snow regime changes in northern Scandinavia by using relatively fine resolution (30 m) Landsat satellite imagery. While snow persistence has not changed in naturally early melting sites, earlier melting has been dramatic in late-melting regions and snowbeds. Hydrological conditions will be disturbed in catchments where latelaying snowbeds have previously provided meltwater until late summer. Changing snow patterns will also alter the distribution of …