基于不同浓度变量的温带落叶阔叶林CO_2储存通量的误差分析  

Error analysis of CO2 storage flux in a temperate deciduous broadleaved forest based on different scalar variables

作　　者：王静[1] 王兴昌[1] 王传宽[1] 

机构地区：[1]东北林业大学生态研究中心,哈尔滨150040

出　　处：《应用生态学报》2013年第4期975-982,共8页Chinese Journal of Applied Ecology

基　　金：林业公益性行业专项(201104009-05);长江学者和创新团队发展计划项目(IRT1054);国家"十二五"科技支撑计划项目(2011BAD37B01);国家林业局重点项目(2006-77)资助

摘　　要：利用帽儿山温带落叶阔叶林通量塔8层CO2/H2O浓度廓线的测定数据,比较分析了基于不同浓度变量[密度(ρc)、摩尔分数(cc)和混合比(χc)]计算CO2储存通量(Fs)的误差.结果表明:通量观测的控制体积内部干空气储存量不为常数,其波动可引起CO2分子进出控制体积,即干空气储存通量调整项(Fsd)的变化.在夜间以及昼夜转换期,Fsd相对于涡动通量而言较大,忽略Fsd将为森林与大气之间净CO2交换量的计算带来误差.大气水热过程对Fs计算引起的误差包括3方面:空气温度变化引起的误差最大,比大气压强(P)的影响高1个数量级;水蒸气的影响在温暖湿润的夏季大于P的影响,但在寒冷干燥的冬季则相反;P的效应在全年均较低.基于ρc、cc和χc计算Fs分别平均高估CO2有效储存通量(Fs_E)8.5%、0.6%和0.1%.在通量计算过程中,建议选择对大气水热过程守恒的χc计算Fs.Using the measurement data from an 8-level vertical profile of C02/H2 0 in a temperate deciduous broadleaved forest at the Maoershan Forest Ecosystem Research Station, Northeast Chi- na, this paper quantified the errors of CO2 storage flux （ F, ） calculated with three scalar variables, i.e. , CO2 density （po）, molar fraction （cc ）, and molar mixing ratio relative to dry air （Xc）. The dry air storage in the control volume of flux measurement was not a constant, and thus, the fluctua- tion of the dry air storage could cause the CO2 molecules transporting out of or into the control vol- ume, i.e. , the variation of the dry air storage adjustment term （ Fsa ）. During nighttime and day- night transition periods, the relative magnitude of F,d to eddy flux was larger, and ignoring the Fsd could introduce errors in calculating the net CO2 exchange between the forest ecosystem and the at- mosphere. Three error sources in the F, calculation could be introduced from the atmospheric hydro- thermal processes, i. e. , 1 ） air temperature fluctuation, which could cause the largest error, with one order of magnitude larger than that caused by atmospheric pressure （P） , 2） water vapor, its effect being larger than that of P in warm and moist summer but smaller in cold and dry winter, and 3） P, whose effect was generally smaller throughout the year. In estimating the effective CO2 stor- age （Fs_E ）, the Fs value calculated with po, co, and Xc was overestimated averagely by 8.5% , 0. 6%, and 0.1%, respectively. It was suggested that in the calculation of Fs, adopting thexc con- servative to atmospheric hydrothermal processes could be more appropriate to minimize the potential errors.

关 键 词：CO2储存通量 有效储存通量 摩尔混合比 空气温度 水蒸气 大气压强 

分 类 号：S718.5[农业科学—林学]