Spatial heterogeneity and temporal variability of greenhouse gas fluxes in permafrost landscapes
Work package 4 examines the spatiotemporal variability of the permafrost carbon cycle. Greenhouse gas fluxes obtained from of micrometeorological eddy-covariance data combined with field observational and remote sensing data will be used for spatial scaling and temporal extrapolation. The landscape characteristics, especially land cover, near surface carbon pools, and cryomorphological landscape dynamics, are needed for upscaling.
© J. Walz: The Arctic in bloom
The generated data allows for the capture of spatial heterogeneity as well as dynamic landscape changes and thus an explicit estimation of near-surface carbon pool in permafrost regions. This is an important requisite for the parametrization of the models in work package 2.
Goals and milestones:
- Survey of the large-scale land cover heterogeneity in northeast Siberia with a high resolution
- Development of transfer functions between field and remote sensing data for estimation of biomass and scaling of carbon pools in northeast Siberia
- Compilation of the temporal variability and analysis of trends of the land cover with high spatial and temporal resolution for the period 1999–2019
- Quantification and deduction of trends in near-surface carbon pools from land cover change
- High-resolution remote sensing of land cover and biomass on floodplains and river terraces
- Synthesis of observational field data about vegetation and near-surface carbon pools for validation of remote sensing data
- Characterization of the temporal evolution of cryomorphological landscape features (polygon types, thermokarst lakes) based on soil and sediments cores from the Lean River Delta
- Quantification of land-atmosphere greenhouse gas fluxes and comparison between floodplains and river terraces as well as synthesis of greenhouse gas measurements with Eddy covariance in other lowlands
- Quantification of the spatial heterogeneity of greenhouse gas fluxes with footprint modeling and high-resolution land cover classification maps of floodplains and river terraces
- Spatial upscaling of greenhouse gas fluxes with data on land cover, biomass, and carbon pools
- Temporal extrapolation of the carbon dioxide and methane fluxes of the river terrace with process-based models with meteorological and vegetation-specific divers to project interannual variability
- Prof. Dr. Ulrike Herzschuh (Alfred Wegener Institute Potsdam)
- Prof. Dr. Guido Grosse (Alfred Wegener Institute Potsdam)
- PD Dr. Julia Boike (Alfred Wegener Institute Potsdam)
- Dr. Lutz Schirrmeister (Alfred Wegener Institute Potsdam)
- Prof. Dr. Lars Kutzbach (Universität Hamburg)
- Dr. Norman Rößger (Universität Hamburg)
- Alexandra Runge (Alfred Wegener Institute Potsdam)
- Iuliia Shevtsova (Alfred Wegener Institute Potsdam)
- Prof. Dr. Dmitry Yu. Bolshiyanov (Saint Petersburg State University and Arctic and Antarctic Research Institute)
- Dr. Irina V. Fedorova (Saint Petersburg State University and Otto Schmidt Laboratory)
- Prof. Dr. Lyudmila Pestryakova (Ammosov North-Eastern Federal University Yakutsk)
- Dr. Mikhail N. Grigoriev (Melnikov Permafrost Institute Yakutsk, Siberian Branch Russian Academy of Sciences)
Book of abstracts
Reports on polar and marine research "Focus Siberian Permafrost – Terrestrial Cryosphere and Climate Change" International Online Symposium, Institute of Soil Science, Universität Hamburg, 24 – 25 March 2021 (Pfeiffer, Eva-Maria, Vybornova, Olga, Kutzbach, Lars, Fedorova, Irina, Knoblauch, Christian, Tsibizov, Leonid and Beer, Christian).
The overall objective was to assess the combination of Landsat and Sentinel-2 data in a mosaic workflow to create good quality annual mosaics for the growing season (July and August) as input for high temporal time series assessments in northern high permafrost latitudes. The combined Landsat and Sentinel-2 input database for mosaics reliably improves the mosaic results without data-gaps. Especially northern, coastal sites often affected by poor cloud conditions benefit from the combined Landsat+Sentinel-2 approach. This work lays the ground for effective and detailed spatio-temporal monitoring and quantification of disturbance dynamics such as thaw slumps and their potential carbon fluxes. (Runge and Grosse, 2020, Remote Sensing).
The decomposition of eddy covariance-based CO2 fluxes into respiration and photosynthesis was not only applied for the overall footprint as commonly carried out, but instead for each of two vegetation classes. In this way, a differing seasonality in the net uptakes of bushes and sedges could be unveiled. Therefore, the flux decomposition proved to be a useful tool for gaining insights into both the phenological dynamic of individual vegetation classes, plus their respective functional flux to flux driver relationships with the aid of ecophysiologically interpretable parameters (Rößger et al., 2019, Biogeosciences Discuss).
20 Years Lena Expedition
German and Russian scientists, technicians, and students will meet in Saint Petersburg from October 17-19 to celebrate 20 years of successful cooperation in the Lena River Delta and Laptev Sea region. Future expeditions and joint research strategies will also be discussed. The meeting is organized by the Arctic and Antarctic Research Institute in Saint Petersburg, the Alfred Wegener Institute in Potsdam, the Melnikov Permafrost Institute in Yakutsk, and the Institute of Soil Science in Hamburg.
© T. Eckhardt: The "old" research station on Samoylov Island
Partitioning of CO2 net ecosystem exchange on the microsite scale in the Lena River Delta shows that both polygon centers and polygon rims were sinks for atmospheric CO2 during a growing season, but the sink strengths varied between the two microsites. Furthermore, it was shown that autotrophic and heterotrophic respiration fluxes react differently to changing hydrologic conditions (Eckhardt et al. Biogeoscience Discuss. 2018)
Greenhouse gas production in degrading ice-rich permafrost deposits in northeast Siberia depends on the climate conditions during deposition. Late Pleistocene Yedoma deposits generally produced more CO2 than Holocene deposits. Thus, organic matter decomposability needs to be interpreted against the paleo-environmental background. However, organic matter decomposability cannot be generalized solely based on the stratigraphic position (Walz et al. Biogeoscience 2018)