| Soil moisture is an improtant element in the process of energy exchagning between the land and atmosphere, it is also an extremely important environmental factor. Jinzhong region located in the east of loess plateau where is lack of water source, and it has internationally recognized as a extremely water-deficient region, and the drought has made great influence to the agriculture. Remote sensing technology has the characteristics of speediness, macroscopic and dynamic, and it has grow into the main method of large-scale drought monitoring and assessing and regional soil moisture resources assess food security. This research retrieved the soil moisture of Jinzhong from May 2014 to September 2014 by use of multi-sources remote-sensing image, it has theoretical and practical significance for abtaining large-scale soil moisture space distribution quickly and duly, as well as preventing and coping the drought effectively.Jinzhong city is one of important producing areas which produced grain, vegetables, herding products and dried-fresh fruits in Shanxi Province, its agricultural industrialization got ahead in Shanxi province since it has advantageous conditions for agricultural production. Jinzhong has developed cutrual tourism, it is a dense distribution area of population and economy; it belongs to warm temperate continental monsoon climate and seasonal change is obvious, space-time location of rainfall is not balanced, and it presents the trend of hilly area in the esat has more rainfall while the plain area in the west has less rainfall.The research of remote sensing technology retrieved the soil moisture is the leading topic of the quantitative remote sensing research. At present, in the remote sensing monitoring research of regional soil moisture, the retrieval model of apparent thermal inertia and normalized vegetation drought index has been widely applied and it has high precision, but the retrieval of single model always ignore the model’s application scale. While little attention paid on the remote sensing monitoring in Shanxi province currently, and which was entirely use the single retireval model, so it is badly in the need of the research in this area.This article take Jinzhong city Shanxi province as the research area, MODIS, Landsat8 and the actual measured soil moisture data as the source of data, refer to the design thought of advantages complementarity, use Normalized Difference Vegetation Index (TVDI) and Apparent Thermal Inertia (ATI) retrieved the soil moisture of Jinzhong from May 2014 to September, and then divide the NDVI value into two part by the number of 0.37, the region which NDVI value is greater than 0.37 ues TVDI method to retrieve soil moisture, while the region which NDVI value is less than 0.37 ues ATI method, and retrieve out the monthly soil moisture of Jinzhong from May 2014 to September 2014, and finally combined with the retrieval images, analysis the space and time distribution charactor of relative soil moisture in the research area, and all the model fitting results have passed the 0.01 significant difference test. The research results show that,1 The relative soil moisture of Jinzhong region in the process of plants growth appeared two change cycles from decline to rise. The first cycle is from May to mid-July, from May to June it decilined while rise from June to mid-July, the peak is in mid-July, at the beginning of June is the growing period and the soil moisture value reached the minimum value, and the average rainfall value in this period is also reached its minimum value. The second cycle is from mid-July to the last ten-day of September. In this cycle, it decilined from mid-July to mid-August while September is the rising period, the peak is at the beginning of August.2 The results of model retrieved precision examination show that retrieval soil moisture has good correlation with the actual measured soil moisture, the retrieved precision is high. |
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