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植被指数和地表温度是描述地表特征的两个重要参数,基于遥感植被指数和地表温度信息进行区域地表水分状况等陆表变化过程研究,是目前遥感和陆表过程研究中的前沿方向。利用MODIS数据产品MOD13A2和MOD11A2获取的归一化植被指数(NDVI)和地表温度(Ts),构建Ts-NDVI特征空间,依据该特征空间计算的温度植被干旱指数(TVDI)作为土壤湿度监测指标,反演了黄淮海平原2004年冬小麦4～5月份和夏玉米7～10月份每16d的土壤湿度,并经相应的土壤湿度数据验证。结果表明:TVDI与土壤湿度显著相关(α=0.05),且反演的黄淮海平原土壤湿度的时空分布特征与农作物生育期规律、生长季总降雨量分布规律基本吻合;特别是0～10cm、10～20cm、20～40cm三个土层中,TVDI更能稳定反映和指示地表10～20cm土壤水分状况,因而TVDI方法适用于黄淮海平原作物生长季的土壤湿度动态监测。
Vegetation index and surface temperature are two important parameters to describe the characteristics of the earth’s surface. Based on the remote sensing vegetation index and surface temperature information, the study on the land surface water conditions and other land surface changes is the front direction in the study of remote sensing and land surface processes. Based on the normalized NDVI and Ts obtained from the MODIS data MOD13A2 and MOD11A2, Ts-NDVI feature space was constructed. According to the TVDI calculated by this feature space as the indicator of soil moisture monitoring, The soil moisture of the Huang-Huai-Hai Plain from April to May 2004 and summer maize from July to October every 16 days was retrieved and verified by corresponding soil moisture data. The results showed that TVDI was significantly correlated with soil moisture (α = 0.05), and the temporal and spatial distribution of soil moisture in the Huang-Huai-Hai Plain retrieved was in good agreement with the law of crop growth period and the distribution of total rainfall in the growing season; especially 0-10 cm, TVDI can reflect and indicate the soil moisture status of 10 ~ 20cm on the surface of soil in 10 ~ 20cm and 20 ~ 40cm so that TVDI can be applied to the dynamic monitoring of soil moisture during the growing season of Huang-Huai-Hai Plain.