中国东北地区玉米农田生态系统生长季碳交换研究

利用中国气象局锦州农田野外观测站的碳通量观测数据分析玉米农田生态系统生长季CO2通量变化.结果 表明,2008～2011年生长季的夜间呼吸速率、白天净碳交换速率年际差异不大,8天累积净碳交换量呈U型分布,碳吸收强度在生长季中期最大.夜间呼吸作用Reco与EVIs×Ws(EVIs和Ws分别为增强型植被指数EVI、陆地表面...

Study on Carbon Exchange of a Maize Agroecosystem during Growing Seasons in Northeast China

Based on the carbon flux data over an agroecosystem in Jinzhou field station of China Meteorological Administration, the changes of CO₂ flux in the growing seasons of the maize farmland ecosystem was analyzed. There was little interannual difference in night respiration rate and daytime net carbon exchange rate in the growing season from 2008 to 2011. The cumulative net carbon exchange in 8 days showed a U-shaped distribution, and the carbon absorption intensity was the largest in the middle of the growing season.The nocturnal ecosystem respiration is linear correlated with EVI_s×W_s(EVI_s and W_s are the functions of enhanced vegetation index and land surface water index on photosynthesis, respectively), and its response to land surface temperature follows L-T equation. The results showed that the respiration model based on remote sensing data was effective in estimating ecosystem respiration, which play an important role in carbon budget assessment of maize farmland ecosystem in Northeast China. In the four years, the growth season of the ecosystem showed carbon sink, and the proportion of carbon consumed by respiration to carbon fixed by photosynthesis was not different. The cumulative carbon exchange capacity was -513.37, -489.86, -482.06, -398.67 g/m² respectively, and the carbon exchange capacity was relatively stable.