敦煌莫高窟蒸散量的估算与非线性分析

通过应用野外称重法测定的折算系数对莫高窟林地的蒸散量进行估算与分析。结果表明,莫高窟林地的年蒸散量为6091mm,符合耗散结构的非线性原理,是较高水平蒸散耗散结构存在的表现。莫高窟林地75%的水分是通过植物根系将深层土壤水分转运出地面后以蒸腾的形式耗散掉的。蒸散量作为各参与因子时空异质性的综合反映,随着土壤水分状况、气候环境、植被种类和植物体量的变化呈现广泛非线性表现。而非线性系统不满足线性叠加原理。因此,本文通过使用折算系数,避免了用蒸发量和蒸腾量的简单的相互叠加,充分考虑了土壤蒸发、植被蒸腾和气候环境之间的相互影响。研究发现,莫高窟林地蒸散量是极干旱气候条件下高水分耗散结构的典型代表。

Estimation and Nonlinear Analysis of Evapotranspiration at Dunhuang Mogao Grottoes

The conversion coefficient measured by the weighing method is used to estimate and analyze the woodland evapo-transpiration at the Mogao Grottoes.The results show that the annual evapotranspiration of woodland is 6 091 mm,in accord with nonlinear theory of the dissipative structure.It is the manifestation that there is a high level evapotranspiration dissipa-tive structure.There is 75% water that is dissipated by transpiration manner,which transports deep soil water to ground through the plant root system.For that evapotranspiration is a concentrated expression of space-time heterogeneity character-istics of all participation factors,it shows a broad nonlinearity with the soil moister,climate condition,vegetation type and the space of plant.Because the nonlinearity system dissatisfies linearity plus principle,the conversion coefficient is used to avoid the simple superposition of evaporation and transpiration,fully considering interaction effects of soil evaporation,vegetation transpiration and climate condition.It＇s found that the evapotranspiration at Mogao Grottoes is a representation of high water dissipative structure under the extremely dry climate condition.