Temporal And Spatial Variation Characteristics Of Agricultural Drought And Its Response To Meteorological Factors In Shanxi

Agricultural drought is due to the imbalance of water supply,resulting in soil water shortage,affecting the growth and development of crops,leading to grain production,and affecting food security and social stability seriously.A variety of other natural disasters,such as forest fires,locusts,shortage of water resources,crop production,land desertification,groundwater level decline caused by the dry season.Accurate monitoring of agricultural drought has attracted much attention of the country for a long time.It's the most important to Studying and mastering its characteristics to prevent agricultural drought and other disasters.On the basis of traditional agricultural drought monitoring and remote sensing drought monitoring model,the digital elevation model(DEM)and latitude correction of land surface temperature(LST)are adopted to obtain the corrected LST.Combined with the normalized difference vegetation index(NDVI)and modified LST constructs the temperature vegetation index(temperature vegetation dryness index,TVDI)drought monitoring model.Andthen,by fitting the improvement of dry edge model,the formation of regional features of Shanxi Province agricultural drought monitoring model TVDI.Based on the reliability verification of the improved TVDI model on 1984-2016 in Shanxi Province,agricultural drought monitoring results,and analyzes the characteristics of drought and evolution of the study area for 33 years.Finally,discusses the dynamic response between agricultural drought changes and climate change.The main conclusions are as follows:1.Compared with the improved TVDI model,the improved model is more accurate and accurate for monitoring agricultural drought in Shanxi.2.Agricultural Drought generally showed a slowing trend in Shanxi.Over the years have droughts,presents non drought to light drought and drought in the vertical belt phenomenon from the west to the north.The province's situation shows:form February to April in the rest of severe drought,light drought or drought,from May to September drought mitigation,October-most of the January regional area as light drought or drought in the province generally;seasonal drought in spring showed increasing trend,others showed a slowing trend.3.During 1984-2016,the space of Shanxi Province Agricultural Drought distribution: in drought or serious drought spread from the northwest to the west,to the eastern and central,and finally to the northwest;light arid areas from central spread to the central and Eastern,and finally to most areas except in the drought or serious drought.Most of the non arid areas are located in Yuncheng,and the summer area is the largest.Autumn drought and DEM elevation distribution showed significant correlation.4.Analysis of relationship between TVDI and temperature,the precipitation show that no significant correlation between TVDI and the average annual temperature,positive and negative correlation area proportion,accounted for the province's total area of 57.3% and 43.7%,the absolute value of thecorrelation coefficient show the eastern is higher than the western;most of the province's annual TVDI and precipitation showed significant negative correlation,negative correlation in the study area more than 79% of the area,more than 60% of the range of the absolute value of the correlation coefficient reached above 0.5,and above the Western Eastern association bounded by the Lv Liangshan.