Improving a PenmanMonteith evapotranspiration model by incorporating soil moisture control on soil evaporation in semiarid areas

作     者：Liang Sun Shunlin Liang Wenping Yuan Zhongxin Chen 

作者机构：State Key Laboratory of Remote Sensing ScienceJointly Sponsored by Beijing Normal University and Institute of Remote Sensing ApplicationsChinese Academy of ScienceBeijingChina College of Global Change and Earth System ScienceBeijing Normal UniversityBeijingChina Department of GeographyUniversity of MarylandCollege ParkMDUSA Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijingChina 

出 版 物：《International Journal of Digital Earth》 (国际数字地球学报（英文）)

年 卷 期：2013年第6卷第S01期

页      面：134-156页

核心收录：

学科分类：09[农学] 0903[农学-农业资源与环境] 090301[农学-土壤学] 

基　　金：the High-Tech Research and Development Program of China(No.2009AA122100) the National Science and Technology Ministry(2012BAH29B02) 

主　　题：ET PenmanMonteith soil moisture MODIS 

摘      要：PenmanMonteith(PM)theory has been successfully applied to calculate land surface evapotranspiration(ET)for regional and global ***,soil surface resistance,related to soil moisture,is always difficult to determine over a large region,especially in arid or semiarid *** this study,we developed an ET estimation algorithm by incorporating soil moisture control,a soil moisture index(SMI)derived from the surface temperature and vegetation index *** denoted this ET algorithm as the *** PM-SMI algorithm was compared with several other algorithms that calculated soil evaporation using relative humidity,and validated with Bowen ratio measurements at seven sites in the Southern Great Plain(SGP)that were covered by grassland and cropland with low vegetation cover,as well as at three eddy covariance sites from AmeriFlux covered by forest with high vegetation *** results show that in comparison with the other methods examined,the PM-SMI algorithm significantly improved the daily ET estimates at SGP sites with a root mean square error(RMSE)of 0.91 mm/d,bias of 0.33 mm/d,and R^(2) of *** three forest sites,the PM-SMI ET estimates are closer to the ET measurements during the non-growing season when compared with the other three *** all the 10 validation sites,the PMSMI algorithm performed the ***-SMI 8-day ET estimates were also compared with MODIS 8-day ET products(MOD16A2),and the latter showed negligible bias at SGP *** contrast,most of the PM-SMI 8-day ET estimates are around the 1:1 line.