Variability in surface water extent in northeastern Arctic Siberia in response to climatic extremes

Abstract:

Climate change is causing Arctic air temperatures to increase at least twice as fast as the rest of the planet on average. Along with the rising temperatures, extreme climate, such as heavy snow and spring heat waves, resulting in flooding and drought, have the potential to release more carbon dioxide and methane due to thawing permafrost and vegetation changes, furthering the climate change feedback loop. Climate models may be parameterized with water extent estimated from low spatial resolution data to estimate emission changes in response to water extent. Depending on the heterogeneity of the landscape, these data may underestimate water surface area due to the inability to detect small ponds, thus potentially underestimating greenhouse gas emissions. We compare high spatial resolution drone imagery (5 cm), Sentinel-2 images (10 m), and data from the Global Surface Water Explorer (30 m) to examine if current methods may be underestimating surface water extent in Kytalyk, northeastern Yakutia, Siberia. The study site is located within the Kytalyk Nature Reserve within the continuous permafrost zone and is representative of an area with no large lakes, but with many small lakes and ponds which are difficult to detect with medium resolution satellite imagery. We present results on the variability of surface water extent in this highly heterogeneous Arctic landscape. We focus on 2017 and 2019, years of flooding and spring drought respectively, to understand surface water dynamics at the site in response to extreme climate. This research aims to highlight the importance of monitoring similar landscapes in the Arctic to gain improved understanding of surface water dynamics and related climate feedback through energy, water, and carbon fluxes.