模拟蒙古栎林生态系统碳收支对非对称性升温的响应  

Simulating the response of the Quercus mongolica forest ecosystem carbon budget to asymmetric warming

作　　者：苏宏新[1] 李广起[1] 

机构地区：[1]中国科学院植物研究所,植被与环境变化国家重点实验室,北京100093

出　　处：《科学通报》2012年第17期1544-1552,共9页Chinese Science Bulletin

基　　金：国家自然科学基金(30900188)资助

摘　　要：夜间最低气温与白天最高气温的非对称性升高现象普遍存在于北半球.应用BIOME-BGC模型模拟了北京东灵山地带性植被蒙古栎林生态系统碳收支在多种气候变化情景下的变化趋势,通过协方差分析探讨非对称性升温对暖温带落叶阔叶林生态系统固碳的潜在效应.结果表明,当大气CO2浓度不变时,对称性升温对GPP和NPP影响不大,但促进了Rh;蒙古栎林生态系统为一个较强的碳源,而非对称性升温则显著地提高了GPP,NPP和Rh,只是Rh的变化幅度较小,碳源功能随着升温不对称性的不断加强而减弱.当大气CO2浓度和气温同时升高时,两者的正交互作用显著地提高了GPP,NPP和Rh,但Rh的变化幅度较小,蒙古栎林生态系统转变为一个较强的碳汇,且随着升温幅度及其不对称性的不断加强,各通量变化幅度增大,碳汇功能不断加强.总之,非对称性升温较对称性升温更有利于蒙古栎林生态系统的碳吸收.鉴于此,推测基于平均气温变化的估算都可能在一定程度上高估了暖温带落叶阔叶林生态系统对气候变暖的正反馈.但该模型模拟的结果还没有得到相应观测和实验的证实.强调今后只有采用协同方法,充分考虑最低气温、最高气温和平均气温各自的生态效应及其与其他生态因子的交互作用,才能更加真实地评价非对称性升温现实世界中森林生态系统的碳源/汇功能.It has been found that nighttime minimum temperature has increased more rapidly than daytime maximum temperature at locations around the Northern Hemisphere in recent years.It is therefore important to understand the differential responses of terrestrial ecosystems to asymmetrical vs.symmetrical diurnal warming,and their consequent influences on ecosystem carbon cycling.We used a well-established,process-based ecosystem model（BIOME-BGC） combined with climate change scenarios,to examine effects of asymmetric temperature change on a Quercus mongolica forest ecosystem carbon budget in North China.Two mean temperatures increases（3°C and 4°C） are applied to baseline daily climate data（1961-1990）.The effects of three different scenarios of temperature change are analyzed（minimum and maximum temperatures raised equally;minima increased two or three times as much as maxima）,under both current and elevated CO2 concentrations.Carbon sequestration was consistently negative under temperature change and current CO2 concentration,and negative effects of temperature declined when minima were increased more than maxima.Sequestration changed to positive under temperature change and elevated CO2 concentration,and positive effects of temperature increased when minima were increased more than maxima.Our results indicate that the potential effects of global change on Quercus mongolica forest ecosytem productivity（GPP and NPP） may be less severe with equal day-night warming than with asymmetric day-night warming.In this view,we suggest that estimates based only on average temperature change may to some extent overestimate the positive feedback of warm temperate deciduous broad-leaf forest ecosystems to climate warming.However,the model simulation results have not been confirmed by corresponding observation and experiment.Only by giving full consideration to minimum,maximum and average temperatures and their respective ecological effects via coordinated approaches,can we more realistically assess forest ecosystem

关 键 词：东灵山地区 暖温带落叶阔叶林 气候变化 BIOME-BGC模型 

分 类 号：X502[环境科学与工程—环境工程]