[BBC03-P06] China’s terrestrial ecosystem carbon balance during the 20th century: An analysis with a process-based biogeochemistry model
キーワード：China, Terrestrial Ecosystem Model, Carbon cycle, Climate change, Land use, Hu Huanyong line
China’s terrestrial ecosystems play a pronounced role in the global carbon cycle. Here we combine spatially-explicit information on vegetation, soil, topography, climate and land use change with a process-based biogeochemistry model to quantify the responses of terrestrial carbon cycle in China during the 20th century. We find that that the regional soil thermal and moisture regimes have dramatically changed. Specifically, evapotranspiration increased due to rising temperature and soils were drying in the last two decades of the 20th century. At a century scale, China’s terrestrial ecosystems have acted as a carbon sink averaging at 0.09 Pg C yr-1, with large inter-annual and decadal variabilities. The regional sink has been enhanced due to the rising temperature and CO2 concentration, with a slight increase trend in carbon sink strength along with the enhanced net primary production in the century. Meanwhile, the heterotrophic respiration increased in response to warming. The spatial and temporal variabilities of carbon balance in China are due to multiple controlling factors including temperature and precipitation and changing atmospheric CO2 concentrations. Land-use changes including reforestation and afforestation during the late 20th century partially contributed to the increase in carbon sink at the national scale.