Analysis Of Meteorological And Hydrological Drought In Shaying River Basin

In this study,hydrometeorological stations data from 1951 to 2008 in Shaying River Basin,is selected to study the trend,mutation and periodicity characteristics of the annual precipitation,average temperature and runoff.Through the analysis of drought frequency,spatial distribution on different time scales adaptability,and drought duration severity,the characteristics of the spatial and temporal of hydrological drought and meteorological drought,response relationship between meteorological and hydrological drought are studied under climate change by using the standardized precipitation index,standardized precipitation evapotranspiration index and streamflow drought index.Three-dimensional joint distribution models for hydrological drought duration,severity and peak is built by the Copula function,and the recurrence period of drought multivariate is also calculated.The main research results are as follows:1.The annual precipitation of Shaying River Basin shows northwest less,more in the southeast,and different in each regions;precipitation in the middle of Shaying River Basin and the north of the upper has a decreasing trend,and upward trend in the south of the middle and reaches downstream,precipitation in Jiangang station has a mutation in 2003,the annual precipitation of Shaying River Basin has periodic variation with the time scale of 9a;the annual temperature ranges from 14.47? to 15.26?,regional temperature difference is less than 1?,the change trend of temperature is upward,and the mutation occurred in 2003,the annual temperature has periodic variation with the time scale of 9a;the annual streamflow series shows a significant decreasing trend,streamflow of Huangqiao station has a mutation in 1976,,and Fugou station in 1975,the annual streamflow has periodic variation with the time scale of 9a.2.Meteorological drought characteristics are analyzed in Shaying River Basin by using SPI(standardized precipitation index)and SPEI(standardized precipitation evapotranspiration index),the results show that two kinds of drought index are similar in spatio-temporal distribution;there are certain differences between two kinds of index and history results in drought years,Generally,SPEI reflects drought more sensitive than SPI,can reflect the Shaying River Basin drought conditions more accurately.3.The variation of hydrological drought at the different time scales can be reflected by the streamflow drought index calculated based on different distributions.On the annual scale,the highest frequency of drought is in the Jialu River,and lowest in the Yinghe River,drought occurrence frequency is consistent in upper and downstream of Shaying River;Hydrological drought is identified by using the theory of runs,the distribution functions of drought variates and correlation coefficient are also proposed,the results show that the best correlation between meteorological and hydrological drought is the time scale of 12 months,and the occurrence of a hydrological drought event lags a meteorological drought event by a variation of 1 to 4 months.4.Three-dimensional joint distribution models of multivariate is constructed by using Copula function models to describe the hydrological drought characteristics,and calculated the recurrence period of variables.The goodness of fit was evaluated,and the results show that Frank Copula function is the best goodness of fit for two-dimensional joint distributions models in drought duration-drought severity,drought duration-drought peak and drought duration-drought peak,indicating M3 copula function is the best goodness of fit for three-dimensional joint distributions models of the multivariate.The recurrence period of single variate is greater than the joint of the two-dimension and three-dimension,but less than the co-occurrence recurrence periods.The relationship between hydrological drought and meteorological drought is researched by the analsis of temporal and spatial evolution characteristics of hydrological drought and meteorological drought in Shaying River Basin,and hydrological drought multivariate joint distribution model is also analyzed,the results will be of benefit to ecological environment protection,agricultural production,inland waterway transport and water resources management.