结合土壤水分可供率改进显热通量估算方法  

An Improved Sensible Heat Flux Estimation Method Combined with Soil Moisture

作　　者：王金龙[1] 张友静[1,2] 郑淑倩[1] 孙璐[1] 

机构地区：[1]河海大学地球科学与工程学院,江苏南京210098 [2]河海大学水文水资源与水利工程科学国家重点实验室,江苏南京210098

出　　处：《地理与地理信息科学》2014年第4期112-116,共5页Geography and Geo-Information Science

基　　金：国家重点基础研究发展计划(973计划)项目(2010CB951101)

摘　　要：通过引入土壤水分可供率因子修正双层遥感蒸散模型中的植被剩余阻抗,以改进表层土壤含水量较小时的植被显热通量估算,并与美国Walnut Gulch流域两个地表通量站的观测值进行比较。实验结果表明:土壤水分可供率遥感估算值与实测波文比换算值的相关系数R2均大于0.84;引入土壤水分可供率改进后的显热通量估算值与实测值的相关系数R提高了0.34;均方根误差在两个通量站分别减少73.5W/m2和97.2W/m2,相对均方根误差均减小15%以上。结合土壤水分可供率的显热通量估算方法能够有效提高估算精度。To improve the sensible heat flux （H） estimation where there is smaller water content in the soil,the authors correct the residual impedance of vegetation in a two-layer evapotranspiration model by introducing soil moisture factor.At present,common evapotranspiration models assume that underlying surface humidity is implicitly embedded in the vegetation coverage,the surface temperature,and so on.In this case,the daily evapotranspiration is often overestimated,in particular for sparsely vegetated and droughty regions,because of an underestimation of sensible heat flux for these areas.The new method remedies this shortcoming by integrating water availability.This decreases residual impedance,and hence increases H.The results of the new method are compared with observation data of two surface flux observation stations in Walnut Gulch Basin in America.It indicates that the correlation coefficient（R2） between remote sensing estimation values integrated with soil moisture and the equivalent value using the measured Bowen ratio are all greater than 0.84,and the correlation coefficient between the improved sensible heat flux estimation value and observation data is improved by 0.34.The root mean square error at the two flux station are reduced by 73.5 W/m^2 and 97.2 W/m^2 respectively,also relative root mean square error are reduced by more than 15%.The sensible heat flux estimation method combined with soil moisture can effectively improve the estimation accuracy.

关 键 词：双层模型 显热通量 土壤水分可供率 剩余阻抗 

分 类 号：S152.75[农业科学—土壤学] TP79[农业科学—农业基础科学]