改进的表观热惯量法反演土壤含水量  

The inversion of soil water content by the improved apparent thermal inertia

作　　者：吴黎[1] 张有智[1] 解文欢[1] 李岩[1] 杨树聪[2] 

机构地区：[1]黑龙江省农业科学院遥感技术中心,哈尔滨150086 [2]中国科学院研究生院,北京100049

出　　处：《国土资源遥感》2013年第1期44-49,共6页Remote Sensing for Land & Resources

基　　金：国家自然科学基金项目(编号:40871021);中国科学院知识创新工程重要方向性项目(编号:KZCX2-YW-448)共同资助

摘　　要：提出一种改进的表观热惯量计算模型,以中科院栾城农业生态系统试验站为基地,通过实测的模型参数,利用提出的表观热惯量模型计算不同植被覆盖下、不同实验区土壤含水量的热惯量值,并与土壤含水量进行相关性分析,以找到热惯量方法可以用来反演土壤含水量的适用条件(归一化植被指数NDVI的阈值)。实验结果表明,该模型监测土壤含水量是可行的,在植被覆盖度较低的情况下(NDVI≤0.35)具有较高的精度,在植被覆盖度较高(NDVI>0.35)时,热惯量模型失效,因此用热惯量方法反演土壤含水量植被覆盖时将NDVI阈值的最大值设为0.35。将该方法应用到MODIS数据中,以河北省栾城县、赵县、藁城市3市县为研究区,分别反演该区土壤含水量,反演结果与实际情况相符合。实地取点人工监测土壤含水量为25.1%,栾城站模型计算结果为22.4%,匹配性较好,该方法在遥感数据中得到了很好的应用。Soil water content is an important indicator for monitoring agricultural drought. The thermal inertia method is one of the primary means for agricultural drought assessment in low vegetation cover. This study proposes an improved calculation of the thermal inertia model. With Agricultural Ecosystem Experimental Station of Chinese Academy of Sciences in Luancheng as a base, the authors measured the thermal inertia values with different vegetation covers and different soil water content concentrations in the experimental zone by measuring model parameters and on the apparent thermal inertia model. The purpose is to find whether the thermal inertia method is applicable to the inversion of the soil water content （ NDVI threshold value）. The validation results show that the monitoring of soil water content of the model is feasible with high precision when the vegetation cover is low （NDVI ~〈 0.35 ）. In high vegetation cover area （ NDVI 〉 0.35 ） , the thermal inertia model fails, and hence the maximum thermal inertia approach to soil water content retrieval vegetation cover （NDVI） is set at 0.35. This method was applied to MODIS data obtained from Luancheng county, Zhaoxian county and Gaocheng city in the study area, and inversion of the area of soil water content was conducted. The results are consistent with the actual situation. Point artificial ground monitoring of soil water content yielded water content 25.1%, and the Luancheng station model calculations yielded 22.4%, suggesting good consistency. It is shown that the method has been applied well in the remote sensing data.

关 键 词：热惯量 土壤含水量 MODIS NDVI 

分 类 号：TP79[自动化与计算机技术—检测技术与自动化装置]