Investigation of three different river systems and floodplain areas in Arctic permafrost regions.

Circumpolar permafrost landscapes are undergoing rapid transition and are strongly affected by climate warming. In these high latitude regions, the rising temperatures are disrupting the thermal equilibrium of the ground, influencing the Arctics moisture levels (wetting / drying) which is driving significant changes in hydrological regimes. The Arctic is a water-rich region with abundant freshwater systems. An important feature of large rivers is their discharge of globally significant quantities of freshwater, dissolved organic carbon, and other materials into the Arctic Ocean, while lakes and rivers also contribute to the global emission of carbon dioxide and methane to the atmosphere.

For this study, three different Arctic river systems were investigated: the Mackenzie (Canada), the Ob (Russia) and the Lena (Russia). We mapped river systems at different levels of detail and localized floodplain-related areas by combining Digital Elevation Model (DEM) analysis with land cover maps (CALU). The floodplain areas are described by the fraction distribution of different land cover units. For example, the majority of the detected units showed water as the dominant unit. After filtering out the water areas, the remaining floodplain areas primarily consisted of wetland. We also separated the areas according to their bioclimate subzones (CAVM) which showed no significant differences in wet/dry units between the subzones; in all cases, wet areas were the majority.

This work contributes to the mapping and characterization of rivers in the Arctic, with a focus on identifying, describing, and analyzing floodplains in relation to river systems. The results will enhance the understanding of Arctic hydrology, providing a foundation for further analysis of the wetting and drying in the Arctic which is the focus of the ERC project Q-Arctic.

Datasets:

• CALU: Bartsch, A., Khairullin, R., Efimova, A., Widhalm, B., Muri, X., von Baeckmann, C., Bergstedt, H., Ermokhina, K., Hugelius, G., Heim, B., Leibman, M., & Gruber, C. (2024). Circumarctic Landcover Units (2.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.14235736
• CAVM: Walker, D. A., Raynolds, M. K., Daniëls, F. J., Einarsson, E., Elvebakk, A., Gould, W. A., Katenin, A. E., Kholod, S. S., Markon, C. J., Melnikov, E. S., Moskalenko, N. G., Talbot, S. S., Yurtsev, B. A., and other members of the CAVM Team (2005). The Circumpolar Arctic vegetation map, J. Veg. Sci., 16, 267–282, https://doi.org/10.1111/j.1654-1103.2005.tb02365.x