Study On Spatio-temporal Evolution Characteristics Of Drought And Vegetation In Sunit Prairie

Sunit prairie is located in the west of Xilin Gol Grassland,a representative area of desert grassland,which occupies a unique position in the grassland animal husbandry economy.In recent years,with the worsening global climate change,overloading and human activities interference.Sunit prairie drought is becoming increasingly serious,is the main factor restricting the livestock production in this area.In this paper,MODIS vegetation products and surface temperature products from 2000 to 2015 were used as the main remote sensing data sources,combined with the field survey data,used 3S technology(Remote Sensing(RS),Geographic Information System(GIS),Global Positioning System(GPS)),temperature vegetation index method and pixel binary model,carried out the study of drought and vegetation dynamics in Sunit prairie,the drought conditions and vegetation status of Sunit Grassland were revealed out from the interannual,seasonal and monthly scales.The main results showed that:1.In recent 16 years,the mean annual temperature vegetation index(TVDI)of Sunit prairie ranged from 0.377 to 0.653,and the perennial average of TVDI was 0.516,The interannual changes of TVDI presented an increasing trend,rate of change was 0.053/10a;The same season and the same month’s TVDI values of different interannual also presented an increasing trend;The interannual dynamic showed that there are two years in normal,ten years in light drought,four years in modereate drought,and the most drought in 2014;The seasonal dynamics showed that spring drought was the most serious drought;The monthly dynamics showed that there were six years in light drought and ten years in moderate drought in May;There were seven years in light drought and nine years in moderate drought in June;There were eleven years in light drought and five years in moderate drought in July;There were six years in light drought and ten years in moderate drought in August;There were four years in light drought and twelve years in moderate drought in September;There were one year in normal,nine years in light drought and six years in moderate drought in October;The wetting and heavy drought were occurred in the interannual,seasonal and monthly.2.In recent 16 years,the interannual vegetation index(TVDI)of Sunit prairie presented an decreacing trend,the growth condition of vegetation was worse in 2005 and better in 2006;NDVI changes in spring and summer of different years presented an increasing trend,and that in autumn presented an decreasing trend;NDVI changes in May,June and July of different years presented an increasing trend,and that in other months presented an decreasing trend.