Abstract
Nearly 25% of all lakes on earth are located at high latitudes. These lakes are formed by a combination of thermokarst, glacial, and geological processes. Evidence suggests that the origin of periglacial lake formation may be an important factor controlling the likelihood of lakes to drain. However, geospatial data regarding the spatial distribution of these dominant Arctic and subarctic lakes are limited or do not exist. Here, we use lake-specific morphological properties using the Arctic Digital Elevation Model (DEM) and Landsat imagery to develop a Thermokarst lake Settlement Index (TSI), which was used in combination with available geospatial datasets of glacier history and yedoma permafrost extent to classify Arctic and subarctic lakes into Thermokarst (non-yedoma), Yedoma, Glacial, and Maar lakes, respectively. This lake origin dataset was used to evaluate the influence of lake origin on drainage between 1985 and 2019 in northern Alaska. The lake origin map and lake drainage datasets were synthesized using five-year seamless Landsat ETM+ and OLI image composites. Nearly 35,000 lakes and their properties were characterized from Landsat mosaics using an object-based image analysis. Results indicate that the pattern of lake drainage varied by lake origin, and the proportion of lakes that completely drained (i.e., >60% area loss) between 1985 and 2019 in Thermokarst (non-yedoma), Yedoma, Glacial, and Maar lakes were 12.1, 9.5, 8.7, and 0.0%, respectively. The lakes most vulnerable to draining were small thermokarst (non-yedoma) lakes (12.7%) and large yedoma lakes (12.5%), while the most resilient were large and medium-sized glacial lakes (4.9 and 4.1%) and Maar lakes (0.0%). This analysis provides a simple remote sensing approach to estimate the spatial distribution of dominant lake origins across variable physiography and surficial geology, useful for discriminating between vulnerable versus resilient Arctic and subarctic lakes that are likely to change in warmer and wetter climates.
Highlights
Quaternary glaciations have left a large footprint on the global freshwater system.The highest densities of freshwater lakes are located at high latitudes (e.g., ~50 and 75◦ N), but concentrated within the limits of the Last Glacial Maximum in Canada, Scandinavia, Russia, and Alaska [1,2]
We mokarst and non-thermokarst lakes, as circular lakes typically integrated lake roundness into the Thermokarst lake Settlement Index (TSI) to improve the discrimination betweenare thermokarst associated with non-thermokarst lakeslakes difference in relief and non-thermokarst lakes, as circular
We focused on the potential resiliency of high-latitude lakes to the suite of geomorphological and climatological processes that can result in drainage and instead examined the linkage between spatiotemporal patterns of lake drainage and lake origin derived by the TSI index
Summary
The highest densities of freshwater lakes are located at high latitudes (e.g., ~50 and 75◦ N), but concentrated within the limits of the Last Glacial Maximum in Canada, Scandinavia, Russia, and Alaska [1,2]. Northern lakes have a variety of origins, including thermokarst (i.e., surface subsidence via ground ice melt), glacial activity that results in depressions (e.g., kettles, cirques) and dams (e.g., ice-dammed and moraine-dammed lakes), and/or hydrogeological processes (i.e., fluvial, floodplain, and coastal erosion) that shape and reshape land surfaces over millennial timescales. Lakes in northern Alaska have four principal lake origins: (i) non-yedoma thermokarst lakes, (ii) yedoma thermokarst lakes, (iii) glacial lakes, and (iv) volcanic origin lakes [3]. Thermokarst lakes (non-yedoma) form in closed depressions by the thaw and collapse of Remote Sens.
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