Study Of Drought Based On MODIS Data In The Mid-west Jilin Province

In Mid-west region of Jilin Province,Drought is one of the frequence meteorological disasters. Continental monsoon climate impacts the middle of Jilin Province,and Mongolian high pressure limits the Western of Jilin Province, which cause inequality spatial and temporal distribution of precipitation. The matching combination of water resources in the spatial and temporal distribution of dislocation phenomena, exacerbating the imbalance between supply and demand of water resources in mid-west region of Jilin Province, eventually induces drought disaster which affects agricultural production and social life. But how accurate, real-time, effective monitoring and prevention drought of the midwest become a problem demanding prompt solution, in order to reduce the losses on agricultural production, human life and ecological environment and so on.In this paper,using product of MODIS between Agust and September from2004to2006with3S technology to calculated six drought vegetation index basis six feature space. Using meteorological observation data to verify the six drought vegetation index. Selecting temperature Enhanced Vegetation Drought Index model through Comparing the six drought index from the vegetation index, the coverage of vegetation, the time resolution.TheTEDI model which is used to monitor the drought of the midwest has a certain practical value and scientific, through the rainfall lines and evapotranspiration validating the TEDI model. Results of exploration and experimentation are as follows:1)Scatterplots of surface temperature and vegetation index from six feature space are basically in line with the triangle relation, the slope of the dry edge is less than0, but the wet edge is larger than0. 2)According to the map of the TEDI drought level,we can observe the spatial distribution of the drought in midwest of Jilin Province:The degree of drought is Gradually increasing from southeast to northwest, especially severe drought, extremely arid area are distributed in Baicheng and Songyuan, which agree with climate change regulation.3)Using the rainfall lines and evapotranspiration data validate the TEDI modle, invention as follows:Extremely arid distribution area almost anastomosis the region which evapotranspiration is greater than900mm; The rainfall line of the severe drought region is less than400mm and evapotranspiration of the severe drought is almost greater than850mm; The evapotranspiration of light drought region is between800-850mm; The evapotranspiration of Normal, humid region is less than800mm, especially the evapotranspiration of humid region is almost less than750mm. The TEDI model which is used o monitor the drought of the midwest has a certain practical value and scientific.4) In Study area, light drought and severe drought were the primary drought, transitional changes of drought rendered by the light drought to extreme drought from southeast to northwest. Heavy drought, extreme arid were concentrated in less than400mm of rainfall region. Severe drought, extreme arid had been expanding, leading to arid gradually deteriorating in region of rainfall from400mm to500mm. Moist areas had been gradually reducing and the light drought had been gradually expanding in greater than500mm of rainfall region.