Snowpatches are sensitive indicators of environmental change in mountain environments because their occurrence reflects interactions among topography, snow redistribution, and climate. Despite their ecological and geomorphological significance, snowpatches have never been systematically documented in the Gasp & eacute; Peninsula (eastern Canada). We combined Sentinel-2 imagery, a multi-year snowpatch recurrence inventory (2014-2025), GIS-derived topographic variables, Random Forest modeling, and climate projections to identify the factors controlling snowpatch distribution and evaluate their vulnerability to future climate change. Recurrent snowpatches were concentrated in a limited number of topographically favorable environments characterized by high elevation, reduced solar radiation, concave landforms, and predominantly east- to southeast-facing slopes. The relative importance of environmental factors associated with snowpatch occurrence differed between Mt. Albert and the McGerrigle Mountains, reflecting contrasts in landscape structure and vegetation cover. Climate projections indicate a substantial decline in regional snow-covered area during the twenty-first century under all future climate scenarios, with the strongest reductions occurring under high-emission pathways. These results demonstrate the strong dependence of recurrent snowpatch occurrence on nested topoclimatic controls and suggest that these features may become increasingly vulnerable under continued climatic warming.
Permafrost regions are vulnerable to forest fires that are increasing under global warming. This study presents the results of field experiments and mathematical modeling of short-term (one hour) forest fires. The experimental site Levaya Shestakovka (Central Yakutia, Russia) has been used as example. Three fire experiments were conducted using logs of Siberian larch and Scots pine which serve as a basis for the mathematical model. The model is based on solving the one-dimensional Stefan problem with unsaturated soil filtration and accounting for snow cover. The lower boundary condition is the geothermal heat flux, while the upper boundary condition is the heat exchange with the atmosphere. The field experiments show that only 8 percent of the heat from the fire has penetrated into the soil, which is supported by our model that indicates no significant effect on heat and mass transfer processes from short-term forest fires into permafrost. The research indicates that the contribution of short-lived forest fires to ground temperature changes is negligible; the heatwave penetrated only 0.5 m into the ground. Modeling showed that short-term forest fires have no significant effect on heat and mass transfer processes in permafrost. Thus, the research results indicate that low-severity forest fire regimes are not significant for permafrost thawing processes.
The stabilization and persistence of organic carbon (OC) in soils and sediments is thought to be governed in large part by association with mineral matrices, especially reactive iron (Fe) phases. However, the role of these organo-mineral interactions has not been fully evaluated in lake sediments that are typically more OC rich. Here, we conducted detailed analyses of three sediment cores collected along a lake-depth gradient from a small clearwater lake in the Swedish Arctic to explore variability in sediment geochemistry and the role of mineral protection in OC preservation. While mineralogy of the two shallower, littoral cores was similar, mostly consisting of (alumino)silicates, sediments in the deepest part also included Fe-oxides and had 6-7 times higher specific surface area, indicating a greater potential for organo-mineral interactions. Higher specific surface area was strongly associated with more thermally-labile OC (rho = -0.71, p = 0.01), but not with OC stocks (rho = 0.05, p = 0.89). Multiple independent proxies indicated that deep-basin OC was more aliphatic, less degraded, and likely of planktonic algal origin compared to shallower regions. We suggest that the spatial pattern in OC quality is not simply a function of different OC sources or hydrodynamic sorting, but it is also regulated by differential capacity for organo-mineral stabilization.
