|Paper title||Above ground biomass and above ground carbon fluxes of the tundra permafrost landscape in the Lena River Delta, Siberia (Russia)|
|Form of presentation||Poster|
Vegetation biomass is a globally important climate-relevant terrestrial carbon pool. In tundra permafrost lowland landscapes North of the treeline, the vegetation low-level structure poses a challenge for the derivation of the plant biomass both, from optical and SAR satellite remote sensing. Still, a range of tundra types have some spectral or structural characteristics for land cover classification. Higher vegetation, such as high-growing shrubs occur in small patch sizes. In this study we investigate to which extent data from Sentinel-2 and Sentinel-1 missions provide a landscape-level opportunity to upscale tundra vegetation communities and biomass for high latitude terrestrial environments.
We assessed the applicability of landscape-level remote sensing for the low Arctic Lena Delta region in Northern Yakutia, Siberia, Russia. The Lena Delta is the largest delta in the Arctic and is located North of the treeline and the 10 °C July isotherm at 72° Northern Latitude in the Laptev Sea region. Vegetation and biomass field data from Elementary Sampling Units ESUs (30 m x 30 m plot size) and shrub samples for dendrology were collected during a Russian-German expedition in summer 2018 in the central Lena Delta.
We evaluated circum-Arctic harmonized ESA GlobPermafrost land cover and vegetation height remote sensing products covering subarctic to Arctic land cover types for the central Lena Delta. The products are freely available and published in the PANGAEA data repository under https://doi.org/10.1594/PANGAEA.897916, and https://doi.org/10.1594/PANGAEA.897045.
We also produced a regionally optimized land cover classification for the central Lena Delta based on the in-situ vegetation data and a summer 2018 Sentinel-2 acquisition that we optimized on the biomass and wetness regimes and extended the land cover classification for the full Lena Delta with consistent Google Earth Engine aggregated Sentinel-2 reflectance covering the summer 2018 period. We also produced biomass maps derived from Sentinel-2 at a pixel size of 20 m investigating several techniques. The final biomass product for the central Lena Delta shows realistic spatial patterns of biomass distribution, and also showing smaller scale patterns. However, patches of high shrubs in the tundra landscape could not spatially be resolved by all of the landscape-level land cover and biomass remote sensing products.
Biomass is providing the magnitude of the carbon flux, whereas stand age is irreplaceable to provide the cycle rate. We found that high disturbance regimes such as floodplains, valleys, and other areas of thermo-erosion are linked to high and rapid above ground carbon fluxes compared to low disturbance on Yedoma upland tundra and Holocene terraces with decades slower and in magnitude smaller above ground carbon fluxes.