09:15 〜 09:30
[MIS01-02] Application of a 3D process-based mathematical model to describe the spatial heterogeneity of vertical CO2 and CH4 fluxes in non-uniform forest and peatland landscapes
キーワード：process-based mathematical model , fluxes of greenhouse gases , forest and peatland landscapes
The modern rapid increase in global temperature by most experts of climate change attributed to the rapid growth of greenhouse gases (GhG) concentrations in the atmosphere from anthropogenic sources. Natural ecosystems also influence the changes in atmospheric concentrations of GhG, releasing carbon dioxide (CO2) into the atmosphere through respiration and absorbing CO2 from the atmosphere during photosynthesis. Modern experimental methods for estimating GHG fluxes have many limitations and requirements that make their application for estimation of atmospheric fluxes very difficult, for example, over non-uniform landscapes. Application of process-based mathematical models can be very useful for describing the GHG exchange between land surface and the atmosphere in those cases when the reliable flux measurements are not possible due to existed methodological constrains.
The main goal of the study is to describe the spatial variability of wind and CO2 fluxes over non-uniform forest and peatland landscapes using a 3D process-based hydrodynamic model, as well as to assess the possibility of the model application for regional flux up-scaling.
The 3D hydro-dynamical model of atmospheric transfer is based on the 1.5 closure scheme of the averaged Navier-Stokes and continuity equations. The exchange of CO2 and CH4 between soil, vegetation and atmosphere within the atmospheric surface layer is described using the equation "diffusion - advection".
The Roshni-Chu forest site in the Chechen Republic at the foothills of the Greater Caucasus Ridge and the ombrotrophic peatland "Staroselsky Moch" at the south-western part of Valdai Hills in Tver region of Russia was selected for our numerical experiments. The model was validated using field flux measurements. Input parameters describing emission and uptake of CO2 and CH4 by soil surface, as well as photosynthesis and respiration rates of leaves were obtained during field studies.
The modeling results showed significant effects of surface topography and vegetation heterogeneity on spatial pattern of vertical and horizontal wind components and vertical and horizontal CO2 fluxes. Maximum air flow disturbances were detected in the near-surface layer at the windward and leeward forest edges, as well as on the hilltops and troughs. The spatial patterns of CO2 and CH4 fluxes vary depending on the prevailing wind direction and the height above the ground.
Field measurement at Roshni-Chu forest site and modeling experiments was supported by state assignment of Grozny State Oil Technical University (Project Reg. No. FZNU-2021-0012). The modeling study in Tver region conducted by I. Mukhartova was supported by Lomonosov Moscow State University (grant number AAAA-A16-116032810086-4) and performed within the Development program of the Interdisciplinary Scientific and Educational School of M.V.Lomonosov Moscow State University "Future Planet and Global Environmental Change".
The main goal of the study is to describe the spatial variability of wind and CO2 fluxes over non-uniform forest and peatland landscapes using a 3D process-based hydrodynamic model, as well as to assess the possibility of the model application for regional flux up-scaling.
The 3D hydro-dynamical model of atmospheric transfer is based on the 1.5 closure scheme of the averaged Navier-Stokes and continuity equations. The exchange of CO2 and CH4 between soil, vegetation and atmosphere within the atmospheric surface layer is described using the equation "diffusion - advection".
The Roshni-Chu forest site in the Chechen Republic at the foothills of the Greater Caucasus Ridge and the ombrotrophic peatland "Staroselsky Moch" at the south-western part of Valdai Hills in Tver region of Russia was selected for our numerical experiments. The model was validated using field flux measurements. Input parameters describing emission and uptake of CO2 and CH4 by soil surface, as well as photosynthesis and respiration rates of leaves were obtained during field studies.
The modeling results showed significant effects of surface topography and vegetation heterogeneity on spatial pattern of vertical and horizontal wind components and vertical and horizontal CO2 fluxes. Maximum air flow disturbances were detected in the near-surface layer at the windward and leeward forest edges, as well as on the hilltops and troughs. The spatial patterns of CO2 and CH4 fluxes vary depending on the prevailing wind direction and the height above the ground.
Field measurement at Roshni-Chu forest site and modeling experiments was supported by state assignment of Grozny State Oil Technical University (Project Reg. No. FZNU-2021-0012). The modeling study in Tver region conducted by I. Mukhartova was supported by Lomonosov Moscow State University (grant number AAAA-A16-116032810086-4) and performed within the Development program of the Interdisciplinary Scientific and Educational School of M.V.Lomonosov Moscow State University "Future Planet and Global Environmental Change".