Combining Landsat and Sentinel-2 Data in High Spatial and Temporal Resolution Time Series Analysis –For A Comprehensive Assessment of Retrogressive Thaw Slumps in High Latitude Permafrost Regions

• Main Authors: Runge, Alexandra, Grosse, Guido
• Format: Conference Object
• Language: unknown
• Published: 2020
• Subjects: Ice; permafrost; Polar Science
• Online Access: https://epic.awi.de/id/eprint/53243/; https://hdl.handle.net/10013/epic.b75792f0-8bb4-4c48-bf8a-d2c27cc506bc

Permafrost is warming globally, which leads to widespread permafrost-thaw, inducing highly dynamic local thaw disturbances impacting their direct surrounding and ultimately resulting in widespread permafrost degradation and loss on local to regional scales. Permafrost-thaw disturbances range from local, rapid single events to regional-scale gradual processes, pulse and press disturbances, respectively. Both disturbance types directly affect the surrounding landscape, ecosystems and infrastructure and further impact hydrological systems, soil carbon accumulation and decomposition and greenhouse gas emissions. Retrogressive thaw slumps (RTS) are highly dynamic pulse permafrost disturbance features. Although mainly locally occurring, they significantly impact the surrounding biogeochemistry, hydrology, and geomorphology. Moreover, RTS influence soil organic carbon stocks significantly as they erode ice-rich permafrost soils deeply and mobilise large volumes of soil and carbon on an annual scale. Previous studies focused on mapping RTS at local sites and deriving dynamic information from individual time snapshots but a continuous and high temporal assessment of the disturbance dynamics as well as the number and distribution of RTS on a pan-arctic scale are still missing. Hence, mapping and monitoring of permafrost disturbance dynamics is essential for assessing and quantifying their impacts and further incorporating the dynamics in large-scale climate models. Remote sensing offers a wide range of assessments possibilities and especially the Landsat archive has been used extensively for high spatial, large-scale land cover changes, as it contains the longest, continuous image archive with data for more than 48 years. However, optical remote sensing is restricted in northern high latitudes due to persistent cloud cover and specific environmental factors such as frequent snow and ice cover, short growing season length, and challenging solar geometry. Despite the continuous acquisition scheme of the Landsat missions, we ...