森林蒸散模型参数的确定

以长白山阔叶红松林为研究对象,利用长白山阔叶红松林气象观测塔安装的常规气象梯度观测系统、开路涡动相关系统的观测数据,依据空气动力学基本理论与能量平衡方程建立了森林蒸散机理模型,确定了模型参数,即风速廓线稳定度订正函数φ_m、温度廓线稳定度订正函数φ_h和零平面位移高度d.其中,研究地的零平面位移高度d为17.8m,是平均冠层高度(26m)的0.68.同时,给出了φ_m和φ_h随梯度理查逊数R_i变化的数学表达式.

Calculation of parameters in forest evapotranspiration model

Forest evapotranspiration is an important component not only in water balance,but also in energy balance. It is a great demand for the development of forest hydrology and forest meteorology to simulate the forest evapotranspiration accurately,which is also a theoretical basis for the management and utilization of water resources and forest ecosystem. Taking the broadleaved Korean pine forest on Changbai Mountain as an example,this paper constructed a mechanism model for estimating forest evapotranspiration,based on the aerodynamic principle and energy balance equation. Using the data measured by the Routine Meteorological Measurement System and Open Path Eddy Covariance Measurement System mounted on the tower in the broadleaved Korean pine forest,the parameters displacement height d ,stability functions for momentum φ_m ,and stability functions for heat φ_h were ascertained. The displacement height of the study site was equal to 17.8 m,near to the mean canopy height,and the functions of φ_m and φ_h changing with gradient Richarson number R_i were constructed.