ALBERT

Description: Uncertainty in carbon cycling in terrestrial ecosystems contributes to overall uncertainty in Earth System Models. In particular, polar terrestrial ecosystems are understudied. Here, we focus on optical and radar remote sensing approaches to understand above-ground carbon dynamics related to vegetation as primary producers in tundra permafrost landscapes. In the ongoing Russian-German research cooperation and joint field expeditions we evaluate the applicability of remote sensing for assessing vegetation stocks and short-term fluxes in the Lena River Delta in the Siberian Arctic. New spaceborne satellite missions such as Sentinel-1, Sentinel-2 and ESA Data User Element DUE Permafrost provide useful services and data for this investigation. i) We evaluated and ground-truthed circumarctic-harmonized geospatial products of land cover and vegetation height from the ESA GlobPermafrost program for the Lena Delta region. The remote sensing products were derived from radar Sentinel-1 and optical Sentinel-2 satellite data. They are findable in the Arctic Permafrost Spatial Center (APGC) (apgc.awi.de) and are published under 10.1594/PANGAEA.897916, [Titel anhand dieser DOI in Citavi-Projekt übernehmen] and 10.1594/PANGAEA.897045 [Titel anhand dieser DOI in Citavi-Projekt übernehmen] . ii) We classified land cover using Sentinel-2 data based on in-situ vegetation data and optimized on biomass and wetness regimes. iii) We investigated the applicability of different land cover products for upscaling in-situ field-based biomass estimates to landscape-scale above-ground vegetation carbon stocks. iv) We investigated how disturbances enhance above-ground vegetation carbon cycling using in-situ data on vegetation community, biomass, and stand age and including remote sensing observations. Our research suggests that subarctic land cover needs to show biomass and moisture regimes to be applicable. Sentinel-1 and Sentinel-2 satellite missions provide adequate spatial high resolution to upscale vegetation communities and biomass in permafrost tundra landscapes. Biomass is providing the magnitude of the carbon flux, whereas stand age is irreplaceable to provide the cycle rate. High disturbance regimes such as floodplains, valleys, and other areas of thermo-erosion are linked to high and rapid carbon fluxes compared to low disturbance on Yedoma upland tundra and holocene terraces with polygonal tundra.