【摘要】 忽略大气层结,考虑气压订正,用冠层整体气孔阻力(rst)代换冠层阻力(rc),蒸散面的净辐射值(Rn)采用冠层截留净辐射(Rnl),便可在叶面积指数(LA I)、林木单叶平均气孔阻力(rsi)和气象要素实测数据的基础上,应用修正后的Penm an-M onteith模型进行林木蒸腾量的模拟。本研究通过对Rn、LA I、rsi的实地观测,确定了林冠截流净辐射(Rnl)、消光系数(k)、冠层阻力转换系数(K’)、空气动力学阻力(ra)和冠层整体气孔阻力(rst),对青海大通地区紫果云杉(P icea purpurea)、华北落叶松(L arix p rincip is-rupp rechtii)、沙棘(H ippophae rhamnoid es)、白桦(B etu la p latyphy lla)和青杨(P opu lus cathayana)的日蒸腾过程进行了模拟,与用快速称重法订正的L i-1600稳态气孔仪实测蒸腾结果对比,模拟的相对误差在±15%以内;模型敏感性分析发现,温度、LA I以及rsi是决定模拟结果的主要参数,模型对各参数变化反应不敏感。更多还原

【Abstract】 If omitting the atmospheric thermal stratification,correcting air pressure,replacing the canopy resistance rst with the canopy integral stomatic resistance r_c,and limiting the net radiation R_n with the canopy intercepted net radiation R_nl in Penman-Monteith equation,the forestry transpiration could be calculated with the measured leaf stomatic resistance r_si and general weather data.In this study,based on the R_nl,extinction coefficient k,transition coefficient of canopy layer stomatic resistance K’,aerodynamics resistance r_a and r_c calculated with the data of R_n,LAI,r_si,the daily transpiration variation of Picea purpurea,Larix principis-rupprechtii,Hippophae rhamnoides,Betula platyphylla and Populus cathayana were studied in Datong County,Qinghai Province.Comparing with the practical transpiration variation measured by Li-1600 Steady Porometer,the relative error of this model was less than ±15%,and the results were stabilized and tested by precision analysis.Therefore,Peman-Monteith model can be applied in forestry transpiration study.更多还原