Research For Temporal And Spatial Variation Of Precipitation And Drought Characteristics In Liao Ning

Liao Ning is in the southernmost part of The three northeast provinces,belonging to temperate continental monsoon climate.The variation characteristics of its climate has a certain representation in the northeast region and even in the north of China.In recent years,the conditon of precipitation and drought changed a lot effected by the climate change,which has affected agriculture,water resources and ecosystem to some extent.therefore the research for the temporal and spatial variation of precipitation and drought characteristics will make great sense to develop ecosystem and water resources.This paper takes the Liao Ning province and surrounding areas as the object of study,building on the precipitation data in 1951?2018 collected from 35 weather station in the areas aforementioned,and applies climate tendency rate,Mann-Kendall test,Z index and other methods to study spatiotemporal variation characteristics of precipitation and drought of Liao Ning.The main conclusion are as follows:1.From the point of view of precipitation trend of Liao Ning,its precipitation is generally on the decline although the downward trend is not clear.Its climate tendency rate is-0.86mm/10a.And the precipitations of Chifeng and Changdao station incline to go down,the others are on an upward trajectory.The average annual precipitations are on the risein spring but they are on the decline in summer,autumn and winter.2.From angle of the amount of precipitation,annual,spring and summer extreme precipitations of liaoning all appear in Kuandian and Kailustation.The maximum and minimum precipitations fluctuateoccur in Jinzhou and Shenyang respectively.The maximum precipitation in winter appears in Kuandin.And the minima is 0mm that occurs in Chifeng,Kailu,et al.3.From the point of view of the spatial distribution of precipitation which of the whole Liao Ning is distributed unevenly.All precipitation from data of each station is increasing from northwest to southeast.The maximum precipitations in spring,summer and autumn all occur in Kuandian station.And the maximum in winter occur inQingyuan.The minima of each season all appear in Kailu.4.By analysing the precipitation of Liao Ning by Trend mutation test,some conclusions can be drawn:From the Annual Trend mutation test,we can get that Changdao and Shuangliao station mutated the latest.And Benxi,Kuandian,Kaiyuan and Chifeng station mutated earliest.Then we can know by making the Vernal Trend mutation test that Xiongyue station mutated the latest,and Anshan,Qinglong and Dalian station mutated earlier than Xiongyue.However Zhangdang station mutated earliest,and Huanren station mutated later than Zhangdang when it was 1957.Additionally,from the Summery Trend mutation test we find that Anshan station mutated the earliest.However Zhangwu station mutated earlist,and Changdao station mutated earlier than Zhangwu.Furthermore,by making the Autumnal Trend mutation test we can see that Qinhuangdao station mutated the latest,and Baoguotu station mutated earlier than Qinhuangdao.However Hengren station mutated earliest.Besides,we can see from the wintry Trend mutation that Chanoyang station mutated earlist.On the contary,Xiuyan station mutated the latest.5.Droughts and floods alternate frequently in Liao Ning region,which occurred 64.7 percent of the time.The frequency of drought was 35.3 percent.The degree of drought in Liao Ning tends upwards,and the probability of continuous drought increases.Its duration is long,and damage is heavy.From the aspect of season,the ratio of drought in spring is on a slow downward trend;but it is on a slow upward trend in the other season.Floods are the most serious in summer and the fall,so we should pay attention to preventing floods,in addition to combating drought.6.From the point of view of the space series,the drought has some obvious regional distribution characteristics.The degree of drought is on the decline from west to east;the spatial distribution of drought is more dispersed in spring,and the rates of drought increase from northeast to southwest.Its rates of summer increase from south to north.The rates of drought of the central part of Liao Ningw are higher in the fall,which increase from west and east end to center of Liao Ning.Its rates increase from southwest to northeast in winter.In summer and autumn,the areas with high rates of drought are widely distributed,which shows that droughts tend to occur in spring and autumn.