A comparative study of carbon fluxes measured at two different heights over an alpine steppe
- 1Deutsches GeoForschungs Zentrum, Geodesy, Potsdam, Germany
- 2Agrosphere Institute (IBG-3), Forschungszentrum Jülich, Jülich, Germany
- 3Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
- 4CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, China
- 5University of Chinese Academy of Sciences, Beijing, China
- 6Institute of Geosystems and Bioindication, Technische Universität Braunschweig, Braunschweig, Germany
Being the most accurate, direct, and defensible method available to date for studying the ecosystem scale gas exchange, the eddy covariance (EC) method was used to examine the net carbon exchange over an alpine steppe ecosystem near the Nam Co Station for Multi-sphere Observation and Research (NAMORS) on the Tibetan Plateau. EC measurements are site-specific and the values represent the total sum of the relative contribution of fluxes from all the components within the footprint over the measurement time. The scattered and uneven distribution of EC towers and their small footprint demand upscaling of the flux observations to a regional scale for improving understanding of the net exchange of CO2 between the terrestrial biosphere and the atmosphere. Regional scale carbon estimates are highly variable and not fully explored as compared to carbon balance studies at extreme ends of the spatial scale spectrum (large continental scale and small vegetation stand scale). Translating the spatially sparse measurements into consistent, gridded flux estimates at the regional scale is a prerequisite for quantifying the current terrestrial carbon cycle. But the uncertainties caused by the representativeness error in the model grids while quantifying the regional estimates of carbon exchange are not fully investigated due to limited data availability as well as knowledge of flux variability at the grid scale. Rather than extrapolating the point scale and/or site-specific scale measurements by fitting any statistical model to predict ecosystem or earth system processes, a systematic upscaling approach is vital for refining mathematical models and accounting for the grid-scale uncertainties for better policy decisions. As an initial step to this, the net ecosystem exchange (NEE) of carbon estimated at two different measurement heights of 3 m and 19 m, in the early growing period of 2019 were used to quantify and analyze the interdependencies in the flux measurements at two heights and the influence of heterogeneity within the footprint in the measured fluxes.
Keywords: Eddy covariance, Carbon flux, Net ecosystem exchange, Tibetan Plateau
How to cite: Pillai, N. D., Wille, C., Nieberding, F., Ma, Y., and Sachs, T.: A comparative study of carbon fluxes measured at two different heights over an alpine steppe, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-13582, https://doi.org/10.5194/egusphere-egu23-13582, 2023.
