Analysis Of Climate And Drought Characteristics In Weihe River Basin From 1960 To 2015

Climate change has become the focus of global attention,because of diversity of climate change since 20 century,and had a huge impact on the Development of Social economy and people's Daily production and Life,It seriously restricts the stable development of the economy and society.The weihe river basin is located in the eastern part of the northwest of China,and plays an important role in social stability,economic development and daily life of residents in the western region.Based on the daily climatic data of meteorological stations in the Weihe River Basin from 1960 to 2015,the climatic characteristics of the Weihe River Basin are analyzed by using the unary linear regression model Mann-Kendall nonparametric test and Morlet wavelet periodic diagram,as well as selecting the optimal Copula function to analysis of drought characteristics of the watershed.Therefore,the change trend of climate and drought in the Weihe River basin in recent years can be reasonably revealed,and the scientific guidance for water resources management in the basin will be provided as well as the theoretical basis for the strategy of developing the western region and the construction of Belt and Road's new Silk Road.The main contents and achievements of this paper are as follows:(1)The average precipitation of the weihe river basin in the past 56 years shows a small decrease in the fluctuation.The area with the largest decrease in rainfall is the Tian-Xi region,with the annual rate of precipitation of-2.76mm/10 a,and the annual average annual rainfall in the Wei-Xian area was the smallest in the study area,and the annual rate of precipitation was-0.54mm/10 a.The region with the largest temperature rise rate is the Lin-Zhen area,with the annual rate of change of 0.37?/10 a,and the region with the lowest temperature rise rate is the Wu-Zhuan region,with the annual rate of change of 0.07 ?/10 a.(2)Years of average rainfall and temperature are averaged over many years there is a different time scale of shock cycles,including the main oscillation cycle is about 25 to 35 years,in addition to the main oscillation cycle,there are a number of different time scales of small oscillation cycle.(3)In the last 56 years,the drought variation law of each region is basically consistent in the whole.The absolute value of SPI increases slightly in fluctuation,the occurrence of drought times increases slightly,and the extreme drought event shows a small decreasing trend,The frequency of extreme drought in the Tian-Xi region has decreased the fastest in many years,which is 3.8 months /year;The multi-year average of the frequency of extreme drought in the Wu-Zhuang region is 3.1 months /year,which is the region with the lowest rate of decline,and the regional nearly 56 years of drought frequency changes are there are multiple cycles,drought changes the frequency of the main shock cycle time scale for 30 years,in addition to the main oscillation cycle there are also a number of small time scale of ups cycle.(4)The Aremeadean family Copula function can well match the correlation between 22 drought feature variables,and the correlation recurrence period between related feature variables is greater than that of the joint return period.