冠层截留对PML模型蒸散发及能量分配的影响
The Influence of Canopy Interception on Evapotranspiration and Energy Distribution of PML Model
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摘要: 冠层截留是地表蒸散发过程的重要组成部分,分析冠层截留对蒸散发过程的影响对提高蒸散发模拟精度有积极作用。基于叶面积指数的遥感Penman-Monteith模型(PML)将蒸散发过程分为土壤蒸发和植被散发两部分,在冠层截留对蒸散发及能量分配影响研究方面关注较少。对PML模型加入冠层截留模块,基于望都站2020年的观测数据进行参数率定和模拟,结果表明:(1)改进后的PML模型在望都站取得较高精度,模拟值与观测值的R2为0.71;(2)望都站冠层截留占年总蒸散发的3.14%,占年降水量的4.37%,土壤蒸发所占比重最大;(3)在引入冠层截留后,PML模拟的土壤蒸发吸收能量下降了3.46%;植被散发吸收能量降低了5.10%。本研究可为认识冠层截留对PML模拟的各蒸散发组分的影响机理提供参考。Abstract: Canopy interception is an important part of the surface evapotranspiration process. Analyzing the influence of canopy interception on evapotranspiration process has a positive effect on improving the accuracy of evapotranspiration simulation. The leaf area index(LAI)based on remote sensing Penman-Monteith model(PML)divides evapotranspiration into two parts:soil evaporation and vegetation transpiration. However,few researches focus on the effect of canopy interception on evapotranspiration and energy distribution. According to the observation data of Wangdu Station in 2020,the parameters of PML model was calibrated and the evapotranspiration was simulated by adding canopy interception module. The results indicate that:(1) the improved PML model achieves high accuracy in Wangdu Station,and the R~2 between simulation and observation is 0.71;(2) the canopy interception accounts for 3.14% of the total annual evapotranspiration and 4.37% of the annual rainfall. The soil evaporation accounts for the largest proportion during the year;(3)with the consideration of canopy interception,the energy for soil evaporation decreases by 3.46% and the energy for vegetation transpiration decreases by 5.10%. This study provides a reference for understanding the effect mechanism of canopy interception on evapotranspiration components of PML model.