青藏高原生态系统固碳释氧价值动态测评

本文旨在定量评价青藏高原生态系统的固碳释氧价值及其动态变化,为改善区域生态环境提供参考。基于MODIS/NDVI数据,利用光能利用率模型测算净第一性生产(NPP)物质量,并通过光合作用方程式换算成固定CO₂和释放O₂的物质量,以此为基础,采用造林成本法和工业制氧法对青藏高原固碳释氧价值量进行估算。结果表明:2000年、2005年和2010年固定CO₂的价值分别为384.36×10⁹元、393.23×10⁹元和356.41×10⁹元,释放O₂的价值分别为408.31×10⁹元、415.02×10⁹元和378.61×10⁹元。2000-2005年固碳释氧价值增加了15.58×10⁹元,2005-2010年下降了73.23×10⁹元,而2000-2010年下降了57.65×10⁹元。固碳释氧价值在空间上呈现出从东南向西北递减的趋势,这与青藏高原的水热条件分布基本一致。在价值构成中,草原>森林>草甸>其它类型>灌丛>农田。2000-2010年青藏高原生态系统固碳释氧价值呈现减小趋势,表明近年来气候变化和人类活动导致青藏高原的生态环境出现了退化趋势。

Dynamic assessment of the values of CO2 fixation and O2 release in Qinghai-Tibet Plateau ecosystem

This article aims to quantitatively evaluate the values of fixing CO₂ and releasing O₂,and their dynamic changes in Qinghai-Tibet Plateau ecosystem.Light energy utilization model was used to estimate Net Primary Productivity(NPP) based on MODIS/NDVI data,and through photosynthesis equation we converted NPP to amount of CO₂ fixation and O₂ releasing.Based on this,forestation cost method and industrial oxygen generation method were used to compute the values of CO₂ fixation and O₂ releasing in Qinghai-Tibet Plateau ecosystem.The results show that the values of CO₂ fixation were 384.36×10⁹ yuan,393.23×10⁹ yuan and 356.41×10⁹ yuan in 2000,2005 and 2010,respectively,while those of O₂ releasing were 408.31×10⁹ yuan,415.02×10⁹ yuan and 378.61×10⁹ yuan in 2000,2005 and 2010,respectively.The values of fixing CO₂ and releasing O₂ increased by 15.58×10⁹ yuan from 2000 to 2005,while they decreased by 73.23×10⁹ yuan between 2005 and 2010.The values of fixing CO₂ and releasing O₂ reduced by 57.65×10⁹ yuan from 2000 to 2010.In terms of spatial distribution,the values of fixing CO₂ and releasing O₂ present a decreasing trend from southeast to northwest,which is consistent with the distribution of heat and water conditions.The values of CO₂ fixation and O₂ releasing are listed in the order of grassland forest meadow other types shrub farmland.The values of fixing CO₂ and releasing O₂ in the Qinghai-Tibet Plateau ecosystem present a decreasing trend from 2000 to 2010,which shows that the climate change and human activities lead to a worsening eco-environment in the Qinghai-Tibet Plateau.