Research On The Relationship Between Soil Moisture And Landform Based On The Remote Sensing Data

Drought is the main natural disasters in Hunan Province. For the specialgeographical position and climate feature, distribution of droughts shows significantregional differences, the recurrent drought often happens in the hilly area in centralHunan Province, so the soil moisture becomes the key factor restricting theconstruction of vegetation in these areas. So to master the spatial distribution of thesoil moisture in this area and the relation ship between them and the environmentalfactor has theguiding significance for this area’s agricultural production andreasonable utilization of the land. The distribution of the soil moisture is badlyaffected by many factors, such as rainfall, vegetation, terrain land use patterns and soon. By taking the terrain and geomorphologic factors as the sample and HunanProvince and Loudi City as the study area,this paper formulate the methods how tostudy the relationship between the terrain and soil moisture by the means of remotesensing and GIS.Through retrieving the soil moisture by the method of remote sensing, thisthesis utilizes the remote sensing image processing method, statistical methodand GIS spatial analysis to study the relationship among soil moisture, terrainand geomorphologic. Trough taking the Hunan Province as the study area and the MODIS data combined with DEM and meteorological data, this paper makesa comprehensive study on the relationship between the physiognomic types. Then draw a conclusion that soil moisture content index distributed on the threephysiognomic types decreases from mountain, plain to hills in order. On thisbasis, by taking the Loudi City located on the hills as the study area and theTM, DEM and meteorogical data as the data source. First, by the method of the qualitative research the terrain niche index formula is used to study the relationship between the TVDI drought grade index and each terrain factor. Resultsshows that the impacts of the elevation and slope on the distribution of the soil moisture is largely consistent, at the aspect of the slope directions, becauseof the prevailing winds, the soil moisture content is greater on the northwestern slope than on the southeastern slope.Then by the method of the quantitative method, in this research, arid and humidsample area where the rainfall is basically the same is selected to study the spatialdistribution of soil moisture located on both sides of the ridge line, different slopes and different elevations, results shows that, there is greater soil moisture in the higherelevation, such as the slope. The distribution at the both sides of the ridgelinesagrees with the effect of the slope directions on the distribution of the soil moisture.Finally, GIS and statistical method is used to analyze the main terrain factors affectedsoil moisture, the influence degree of each factors is slope, elevation, slope positionand aspect. It is shown by the comparison between data obtained from calculation andtests that the result is consistent with the reality.