Research On Drought Monitoring And Drought Index Applicability Analysis In Shandong Province Based On Remote Sensing

With the development of science and technology,the acquisition of remote sensing satellite data is more and more convenient,and using the remote sensing big data technology to monitor drought of crops has become one of the hottest research focus in agriculture.Winter wheat is the main crop in Shandong.In recent years,frequent droughts in Shandong have caused a significant reduction in production of winter wheat.At present,there are many indicators for evaluating drought,but both the calculation methods of drought index and the applicability in different study areas are different,so choosing a suitable drought index is of great significance for studying the drought problems of winter wheat in Shandong.The purpose of this article is to use MODIS data to construct a remote sensing index,discuss the applicability of each remote sensing index,select the drought index with the highest applicability,and analyze the changing characteristics of drought of winter wheat at critical growth stages and the spatial distribution and changing trends of the drought during 2001-2015 in Shandong Province.The research is important to the improvement of winter wheat yield in Shandong province,and can also provide useful references for the prevention and control of drought in Shandong province.And it's helpful to improve drought control work and reduce the unnecessary loss of crops caused by drought in the critical time of drought.The conclusions are as follows:(1)From 1951 to 2015,the Pa value of the whole province showed a downtrend,and the trend of dryness increased.From 2001 to 2015,the drought degree in the critical growth period of winter wheat in 2011 was severe,wide range of space and long duration.(2)During the growth period of winter wheat,three indexes are suitable for drought monitoring of shallow soil water.(3)The three remote sensing indexes are all applicable to drought monitoring in Shandong,but the monitoring effect of NVSWI index is obviously better than that of NDVI and NDWI in combination with spatial and temporal distribution and other factors.(4)The NVSWI have strong interannual changes,and there is a one-month lag between them and meteorological elements.(4)During the critical growth periods of winter wheat from 2001 to 2015(March-May),the frequency of drought in western decreased gradually,while the trend of drought in central and southern and eastern coastal areas increased.