稻田甲烷排放模型研究——模型灵敏度分析  

Modeling methane emission from rice paddies: model sensitivity analysis

作　　者：张稳[1] 黄耀[1] 郑循华[1] 于永强[1] 

机构地区：[1]中国科学院大气物理研究所,北京100029

出　　处：《生态学报》2006年第5期1359-1366,共8页Acta Ecologica Sinica

基　　金：中国科学院知识创新工程重大资助项目(KZCX1-SW-01-13)~~

摘　　要：模型方法对区域稻田甲烷排放估计的不确定性主要源于模型参数在区域范围内的误差,这种误差导致的估计不确定性由模型灵敏度决定.采用一种动力学分析与统计分析相结合的方法对稻田甲烷模型CH4MOD进行了参数灵敏度分析,结果表明,稻田水管理方式的灵敏度最高,灵敏度指数为O.64,其次为稻田土壤的砂粒含量参数,灵敏度指数0.50,灵敏度最低的参数是水稻移栽期地上生物量.以模型灵敏度指数为基础,建立了模型估计值不确定性与模型参数区域化误差间的数量关系,利用这一量化关系得出我国2000年稻田甲烷排放的不确定性范围为3.09～10.61Tg.此外,模型灵敏度参数的大小也反映了模型要素对稻田甲烷排放影响的大小,因而分析的结果对于采取合理措施减少稻田甲烷排放具有指导意义.Model estimates of methane emission from regional and global rice paddies have been gaining international interesting. Structurally, methane emission models are characterized in terms of their component processes and their inter-relationships. Once a model is developed, it is necessary to take into account the many sources of uncertainty in the processes modeled. Uncertainties of model estimates come primarily from spatial database errors when up scaling is performed, while the magnitude of the uncertainties induced by the database errors depends straightly on the sensitivity of model output to the input parameters. The objective of this paper is to develop a methodology of sensitivity analysis applicable to a methane emission model CH4MOD, and to further link the sensitivity analysis with the spatial database errors for assessing the uncertainties of model estimates of methane emission from Chinese rice paddies. Sensitivity of CH4MOD output to the model input is characterized by a sensitivity index defined as a ratio of relative change of model output （dy/y） to that of model input parameter （ dx/x）. By applying the statistical analysis on a vast amount of model outputs against the random combinations of the model parameters, the sensitivity index was first calculated for each parameter in CH4MOD. The uncertainties of CH4MOD output were then assessed by linking the sensitivity index with the spatial database errors. The parameters in CH4MOD include soil sand percentage （Sand）, rice variety index （VI） and grain yield （ GY）, rice aboveground biomass at transplanting （ W0 ） and the intrinsic growth rate of aboveground biomass （ r）, organic matter amendment （OM） and irrigation regime （ Wptn ）. Sensitivity analysis showed that the irrigation regime is the most sensitive factor with a sensitivity index of 0.64. The sensitivity of remaining parameters is ranked by their sensitivity indices as Sand （0.50） 〉 VI （0.48） 〉 OM （0.43） 〉 r（0.42） 〉 GY （0.32） 〉 W

关 键 词：CH4MOD 模型 灵敏度 不确定性 

分 类 号：S511[农业科学—作物学]