利用“模拟—校正”法估算黄土高原半干旱区陆面蒸散发  

Estimation of Terrestrial Evapotranspiration of Grassland in Semi-arid Region of the Loess Plateau by Simulation-Correction Method

作　　者：杨扬[1] 孙旭映[1] 张良[1] 王丽娟[1] 胡蝶[1] YANG Yang;SUN Xuying;ZHANG Liang;WANG Lijuan;HU Die(Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu(CMA),Institute of Arid Meteorology,CMA,Lanzhou 730020,China)

机构地区：[1]中国气象局兰州干旱气象研究所甘肃省(中国气象局)干旱气候变化与减灾重点实验室,兰州730020

出　　处：《水土保持研究》2020年第2期178-184,192,共8页Research of Soil and Water Conservation

基　　金：国家自然科学基金重大培育项目(91637106);公益性行业(气象)科研专项重大专项(GYHY201506001-4);中国气象局兰州干旱气象研究所干旱气象科学研究基金(IAM201815).

摘　　要：研究区域气候变化及干旱监测,需要准确估算陆面蒸散发。利用兰州大学半干旱气候与环境监测站SACOL的观测资料,以CLM模式模拟的蒸散发量和MODIS观测的归一化植被指数(NDVI)为基础,构建了一种"模拟—校正"的新方法,用于估算黄土高原半干旱区草地下垫面的蒸散发。结果表明:CLM较好地模拟了蒸散发的变化趋势,但模拟值较观测值存在较大的偏差。干旱条件下CLM模拟的蒸散发相对误差与NDVI成正比,随NDVI的增大而增大;湿润条件下,相对误差与NDVI之间满足二次曲线变化规律。经过新方法校正CLM模拟的蒸散发以后,估算的蒸散发与观测值间的偏差显著降低,平均偏差由9.71 W/m^2减小到2.77 W/m^2,均方根偏差由34.16 W/m^2减小到8.58 W/m^2,相关系数由0.67增加到0.94。"模拟—校正"法由于考虑了植被的作用改进了黄土高原半干旱区蒸散发的估算效果。In order to study regional climate change and drought monitoring,it′s necessary to estimate terrestrial evapotranspiration accurately.Based on the observation data of Semi-Arid Climate Observatory and Laboratory of Lanzhou University(SACOL),the evapotranspiration simulated by Community Land Surface Model(CLM 4.0)and the normalized vegetation index(NDVI)observed by MODIS,a new method named simulation-correction was developed to estimate the terrestrial evapotranspiration over the semi-arid region of Loess Plateau.The results show that CLM can simulate the trend of terrestrial evapotranspiration well,but there are some deviations between the simulated and observed values;the relative error of simulated evapotranspiration under dry condition is proportional to NDVI,and the relative error increases with the increase of NDVI;the relationship between the relative error of simulated evapotranspiration and NDVI under wet condition follows the quadratic curve;the deviation between calculated evapotranspiration and observed values was significantly reduced after CLM simulation is corrected by the new method;compared to CLM,the MBE decreases from 9.71 W/m^2 to 2.77 W/m^2,while the RMSE decreases from 34.16 W/m^2 to 8.58 W/m^2 and correlation coefficients increase from 0.67 to 0.94.The‘simulation-correction’method improves the estimation accuracy of terrestrial evapotranspiration over the semi-arid region of the Loess Plateau due to considering the vegetation.

关 键 词：蒸散发 陆面过程模式 归一化植被指数 “模拟—校正”法 干湿环境条件 

分 类 号：P426.2[天文地球—大气科学及气象学]