Perennial snow patch detection based on remote sensing data on Tröllaskagi Peninsula, northern Iceland

Abstract

The understanding of permafrost distribution in Iceland is still limited and current knowledge is mainly based on small scale observations and regional modelling using temperature data. In the Alps Perennial Snow Patches have been considered to protect permafrost from solar radiation and are used as an indicator for the occurrence of local permafrost. In this study perennial snow fields are detected and classified based on aerial and satellite images. Effects of climatic and topographic factors on the snow field occurrence are investigated aiming to provide insight into the distribution of local permafrost in northern Iceland. Multi-temporal optical satellite images (Landsat-5/-7/-8 and Sentinel-2, 1984–2017) have revealed a time-variable distribution of perennial snow patches as possible permafrost indicators on the Tröllaskagi Peninsula in northern Iceland. Calculated normalized difference snow index in combination with different threshold values at the end of summer season within six selected study areas show that several snow patches are present in a time period of over 30 years. Perennial snow patches in the study areas exhibit strong fluctuations in extent due to different local characteristics, e.g. elevation, aspect or topography (plateau/open slopes vs. valleys/cirques). In three of the six study areas snow patches have a high probability of occurrence and the pattern of the distribution is very similar in each time period. Comparison with climate data from nearby weather stations indicates that perennial snow patches can be used in combination with mean annual air temperatures as indicators for local permafrost distributions.

Decline of Late Spring and Summer Snow Cover in the Scottish Highlands from 1984 to 2022: A Landsat Time Series

“…A field survey in the Snowy Mountains of Australia [14] found that winter snowfall, wind direction and summer warmth all influenced snow patch duration. An Icelandic satellite survey [13] also showed winter snowfall and mean annual temperature to be important factors.…”

“…Perennial snow patches are a widespread feature of montane and arctic landscapes worldwide, and recent years have seen studies on this feature in Scotland [11], the Canadian arctic [12], Iceland [13], Australia [14] and Scandinavia [15]. Snow patch duration and survival is related to climatic factors such as winter snowfall and seasonal temperatures [11][12][13][14][15].…”

“…Perennial snow patches are a widespread feature of montane and arctic landscapes worldwide, and recent years have seen studies on this feature in Scotland [11], the Canadian arctic [12], Iceland [13], Australia [14] and Scandinavia [15]. Snow patch duration and survival is related to climatic factors such as winter snowfall and seasonal temperatures [11][12][13][14][15]. Declines in summer snow cover have been suggested in some regions such as the Snowy Mountains of Australia [14], but high interannual variability and issues with consistent monitoring can obscure potential trends.…”

“…Landsat has sufficient spatial resolution (30 m) for use in the detection of even small snow patches and has an archive of uninterrupted imagery dating back to 1984. [13] used this Landsat archive to map perennial snow patches in northern Iceland, with the results validated by aerial photography and field surveys. [15] used Landsat imagery from 2000, 2004, 2006 and 2009 to map late summer snow patches in northern Finland.…”

The impact of ground-ice thaw on landslide geomorphology and dynamics: two case studies in northern Iceland

“…(Andrés et al 2016). Perennial snow patches (Tussetschläger et al 2020), active rock glaciers and stable ice-cored moraines are abundant in the region (Farbrot et al 2007a;Lilleøren et al 2013), with the latter two being used to calibrate numerical models of mountain permafrost (Farbrot et al 2007b;Etzelmüller et al 2007). The lower mountain permafrost limits in Tröllaskagi have been modelled at 600-900 m a.s.l.…”