Analysis Of Drought Characteristics In Shandong Based On Remote Sensing Data

Drought is one of the frequent natural disasters in Shandong Province.It is of great significance to accurately monitor the occurrence time,severity and impact scope of drought for the economic development and environmental improvement of Shandong Province.At present,many drought monitoring indexes have been proposed by scholars at home and abroad,and each index has different adaptability in different regions,land types and vegetation types.Based on the previous drought monitoring model,this paper quantitatively evaluates the applicability of remote sensing drought index in Shandong Province through the site measured data,and further analyzes the temporal and spatial characteristics of meteorological drought and agricultural drought in Shandong Province.The main contents of this paper are as follows:(1)Based on the measured precipitation data and remote sensing TRMM Precipitation Data,the meteorological drought index data set is established to evaluate the accuracy of TRMM remote sensing data,and the temporal and spatial variation characteristics of meteorological drought in Shandong Province are further analyzed based on standard precipitation index and normalized precipitation anomaly index.The results show that the precipitation values of 24 weather stations are similar to those of TRMM,and their Pearson correlation coefficient is 0.95,and the accuracy of TRMM remote sensing data is high.The autumn months and northwest areas of Shandong Province are prone to droughts.The occurrence of meteorological droughts tends to be higher in frequency and shorter in duration.(2)Based on the soil moisture data and remote sensing MODIS data of the station,the normalized drought index nddi,drought severity index DSI and temperature dependent index TVDI agricultural drought index data set are established,and the adaptability of agricultural remote sensing drought index in Shandong area is evaluated quantitatively from different time scales.The results show that the accuracy of DSI monitoring drought in Shandong is higher than nddi and TVDI on the whole;DSI can well reflect the meteorological drought caused by the lack of precipitation,and also can well reflect the agricultural drought caused by the lack of soil moisture in some months,which can be effectively used for remote sensing monitoring of drought in the east of Shandong.(3)Based on DSI's long time series data set,the spatial distribution and temporal and spatial variation characteristics of drought in Shandong Province from 2000 to 2017 were analyzed by linear trend analysis and frequency analysis.According to the spatial distribution characteristics of drought,the western and central areas of Shandong Province are more prone to drought than the eastern areas.In January,February in winter and March in spring,it is prone to continuous drought and humid in summer.From the point of view of temporal and spatial evolution,the fluctuation range of drought in Shandong is not large,but in the normal range as a whole.The severity of spring drought continued to decrease from 2011 to 2017;summer remained wet all year round;autumn drought fluctuated near the drought boundary.After 2006,the winter drought kept fluctuating under the drought demarcation line,and there was a general trend of alleviation.The frequency of drought in the west,the South and the northeast of Shandong Province is decreasing as a whole.The frequency of drought in the middle and the southeast of Shandong Province is increasing,but the change trend is not significant.The innovation of this paper is as follows:(1)In the process of evaluating the applicability of agricultural drought index,previous studies mostly extract the pixel information of the corresponding position of remote sensing data according to the longitude and latitude position of the site,and further use the site data to evaluate the applicability of remote sensing drought index.There are spatial mismatches between the site data and the remote sensing data,and the land type of the site is non farmland,which leads to large errors in the evaluation results.In this paper,we use the classification results of land use types,eliminate the construction land area,and then use the mean synthesis method to calculate the remote sensing data on the scale of prefecture level cities,so as to evaluate the applicability of remote sensing drought index more accurately.(2)At present,there are few researches on long-term drought monitoring in Shandong Province.In this paper,the long-term drought index data set of 2000-2017 is established,and the drought change law of Shandong Province in a long historical period is analyzed,which provides a reference for drought monitoring in Shandong Province with a relatively new time effect and a longer time series.