华北平原冬小麦冠层导度的环境响应及模拟  

The environmental responses and simulation of canopy conductance in a winter wheat field of North China Plain

作　　者：黄辉[1] 于贵瑞[1] 孙晓敏[1] 王秋凤[1] 赵风华[1] 李俊[1] 欧阳竹[1] 

机构地区：[1]中国科学院地理科学与资源研究所

出　　处：《生态学报》2007年第12期5209-5221,共13页Acta Ecologica Sinica

基　　金：国家自然科学基金"杰出青年基金"资助项目(30225012);国家自然科学基金重大资助项目(30590381)~~

摘　　要：通过引入叶面积指数,将叶片水平的气孔导度组合模型扩展到冠层水平,建立了冠层导度环境响应组合模型,组合模型所需参数较少,且均可在冠层水平直接测量,便于应用;模型由潜在气孔导度(PSC)和相对气孔开度(RDO)组成,二者分别由环境变量的日际(inter-day)和日间(intra-day)的值决定。分析表明,冠层导度在日际尺度和日间尺度上对环境变量具有多尺度响应特性,在日际尺度上,温度是影响冠层导度的主要因子,在日间尺度,光是影响气孔开闭的主要因素。利用以温度和光合有效辐射为输入变量构建的组合模型,模拟了华北平原冬小麦农田生态系统的冠层导度,并用Penman-Monteith方程估算的表面导度进行验证。结果显示,在不同天气情况下,二者的日变化均具有较好的一致性;将组合模型与电学类比模型结合,进一步估算了拔节-灌浆期的冠层潜热通量,利用涡度相关系统观测的潜热通量数据进行验证,结果表明对冬小麦冠层潜热通量模拟精度较高,直线回归斜率为0.7054,R2=0.7894。A leaf-scale combination model was modified to estimate canopy conductance （ Go ） by introducing leaf area index （L）. The modified model used only air temperature （T） and photosynthetically active radiation （Qp） as input variables, which can be measured directly. The Gc is the product of the potential canopy conductance （ PSC）, which is the Lnormalized maximum Gc （GMax）, and the relative degree of stomatal opening （RDO）, which is the L multiplying by Gc normalized with GMax The PSC is estimated from the maximum values of T, and the RDO is estimated from diurnal variation of Qp normalized by the maximum Qp. We applied the modified combination model to a winter wheat ecosystem in North China Plain. We also estimated canopy-scale latent heat flux （λEc） by coupling the combination model with the analogy of Ohm＇s law in electrics. Simulated λEc for the winter wheat ecosystem was compared with that calculated from inverted Penman-Monteith equitation, and estimated λEc with observation by the eddy covariance system. The combination model yielded a quite well diurnal dynamics of Go. Estimated λEc was in good agreement with that measured directly with the eddy covariance method. The slope and R2 of the line regression between the observed and simulated λEc are 0. 705 and 0. 79 （n= 1526）, respectively .

关 键 词：冠层导度 组合模型 涡度相关 潜热通量 多尺度响应 

分 类 号：S512.1[农业科学—作物学]