Inversion Of Soil Moisture Based On The MODIS And Its Application In Watershed Hydrological Model

Soil moisture status is one of the important indicators for monitoring soil conditions, and also is the basic information for agriculture, hydrology and meteorology as well as in other fields. Soil moisture changes with spatial and temporal variation which has obvious influence on heat balance between land and atmosphere, soil temperature and soil moisture condition. The macroscopic and dynamic distribution characteristics of soil moisture can provide valuable information for the monitoring of soil drought, regional flood disaster and land deterioration. Traditional methods to measure soil moisture have high precision while are time-consuming and difficult to be widely and dynamically. With the3S technology development, the using of remote sensing technology to monitor soil moisture becomes a hot research topic.In this study, the standard data product of MODIS such as MOD11A2and MOD13A2and30meters resolution DEM were selected as data source. Firstly, using the method of feature space, which proposed by the land surface temperature (LST) and the vegetation index (Ⅵ) to inverse the surface soil moisture of Zhejiang Province. Using of soil moisture DEM hydrological factors and real-time water rainfall information as input parameters, and combining with watershed hydrological model to simulation river section production flow. Finally, a set of software was developed that contains the above functions. This paper mainly includes the following contents:(1)Inversion of the surface soil moisture based on the MODISThe temperature vegetation dryness index (TVDI), which reflected the trend of dry and wet soil, was converted into relative soil moisture (RSM). Then the RSM was divided into five classes according to risk analysis. The same phase of field survey data was used to validate the inversion results, demonstrating that TVDI index was significantly correlated with the soil moisture in the depth of20cm which can better reflect the depth of soil moisture.(2)The runoff yield of the cross-section in the river basin based on the Xin’anjiang modelThe river basin was extracted by the30meters resolution DEM. And the inversed relative soil moisture was used as the initial parameters of the Xin’anjiang model to calculate runoff yield. Correlation analysis showed that the inversion results were better related with measured data.(3)The development of Hydrological information integrated monitoring and flood forecasting system The software named Hydrological information integrated monitoring and flood forecasting system was developed using Microsoft VS2008and the component GIS development technology. The application is characterized by the function modularization, including remote sensing data processing, inversion of the soil moisture and runoff yield calculation. It has a low degree of coupling between the functional features.