基于遥感数据的宁夏地区土壤水分反演方法比较

Comparison of soil moisture inversion methods with MODIS data in Ningxia

利用MODIS产品数据MOD11A2和MOD13A2获取地表温度(TS)、昼夜温差(DST)、归一化植被指数(NDVI)、增强植被指数(EVI),构建宁夏区域2005年4、7、10月逢8、18、28日TS-NDVI、TS-EVI、DST-NDVI、DST-EVI特征空间,根据TS-NDVI、TS-EVI、DST-NDVI、DST-EVI特征空间建立了温度植被干旱指数(TV-DI)、温度增强植被指数型干旱指数(TE-DI)、温差植被干旱指数(DTVDI)、温差增强植被指数型干旱指数(DTEDI),并以这些干旱指数作为土壤水分监测指标,反演了宁夏区域2005年4、7、10月的土壤水分.利用实测10cm土壤水分进行相关分析,结果表明DTEDI在宁夏土壤水分反演中表现较好,DTVDI表现略好.

MOD11A2 and MOD13A2 （data of MODIS） are used to get surface temperature （TS）, temperature difference between day and night （DST） ,normalized difference vegetation index （NDVI）, enhanced vegetation in- dex （EVI） to construct characteristic space of TS-NDVI,TS-EVI, DST-NDVI and DST-EVI in April （8th, 18th and 28th）, July （ 8th, 18th and 28th） and October （ 8th, 18th and 28th） of 2005 in Ningxia region. Temperature Vege- tation Drought Index （TVDI）, Temperature Enhanced Drought Index （TEDI）, Difference Temperature Vegetation Drought Index （DTVDI） and Difference Temperature Enhanced Drought Index （DTEDI） are established according to characteristic space of TS-NDVI, TS-EVI, DST-NDVI and DST-EVI. These drought indexes are used as monito- ring index to retrieve soil moisture in April,July and October of 2005 in Ningxia region. Correlation analysis between observed 10 cm soil moisture and retrieved data is conducted,and the result shows that DTEDI is best,and DTVDI is better than TVDI and TEDI in retrieval results of soil moisture in Ningxia region.