Evolution Of Hydrologic Drought In Shandong Provnice

As a major province of economy,population and agriculture,Shandong province is restricted by the shortage of water resources.In addition,the frequent occurrence of drought in Shandong province has seriously affected the economic and social development.Therefore,the analysis and prediction of hydrological drought evolution rule will play a positive role in alleviating the adverse effects on agriculture and life caused by drought.This paper is based on the hydrological and meteorological data of 125 stations in 17 cities of Shandong province from 1961 to 2015 and analyzed its variation characteristics.Use the standardized precipitation index method(SPI)to analyze the hydrological drought.On this basis,the hydrological drought duration and drought intensity were statistically analyzed by using the run length theory,and the correlation between each factor and the hydrological drought index was analyzed.Finally,the future drought was predicted by using the Hurst index method.The main conclusions are as follows:(1)The average annual precipitation in Shandong province showed a small fluctuation trend.The abrupt change of precipitation was likely to occur in 2008.The wavelet analysis method is used to obtain that there are multiple characteristic time scales of annual precipitation in Shandong province,which are 3-5 years,7-16 years,35-42 years.The main cycles are 12 years and 24 years.The average evaporation in Shandong province was showed a significant downward trend.The possible mutation occurred in 1990,1993 and 1995.There are several characteristic time scales of annual evaporation in Shandong province,which are2-6 years,9-13 years and 21-30 years respectively.The main cycle is 27 years.The average runoff in Shandong province was on a downward trend.The possible mutation years were1966,1970,1972,2003,2006,2010 and 2013.There are several characteristic time scales of annual runoff in Shandong province,which are 3-7 years and 11-35 years respectively,and the main cycle is 14 years.The negative contour line of the cycle chart of precipitation,evaporation and runoff in 2015 has not been closed,indicating that it will still be in a state of low after 2015.(2)Shandong province has a high frequency of mild drought level,followed by moderate drought level.Until the 1980 s basic have light drought of Shandong province is given priority to,the lowest overall drought frequency,between the 1990 s and 1980 s,heavy drought rise sharply and the frequency of drought,the frequency of drought had also greatly improve,to the end of a time series,the increase in the frequency of drought.In terms ofyears,successive droughts occurred every ten years or so,the frequency of winter and spring continuous drought was higher.Regionally,Dongying,Dezhou and Liaocheng in the north and west of Shandong province are drought-prone areas.(3)From the drought intensity,for Shandong province,it can be found that the short-term drought occurs most frequently when the time scale is one month.Season's drought was more occured in three month time scale.In the 12 month time scale,a number of long-term droughts occurred.(4)The correlation between evaporation and drought index was not significant,but the correlation between runoff and drought index was strong.The drought conditions calculated by the standardized precipitation index also indicate that the drought frequency increased,and the drought may continue in the future.Moreover,according to the results of Hurst index analysis,it can be concluded that the drought situation in Shandong province will continue,which verifies the previous prediction.