Influence Of Moisture Sources On The Hydrogen And Oxygen Isotopes Of Precipitation In Shanxi Province

Isotopic fractionation,which runs through all aspects of water cycle,is very sensitive to environmental changes.It is known as the"fingerprint"of water.It is the main means to trace the source of atmospheric precipitation water vapor and the process of atmospheric circulation.Among the many factors that affect the stable isotope characteristics of precipitation,the variation of moisture sources area first affects the fractionation of stable isotopes.Based on the migration process of moisture mass and the environmental characteristics of precipitation area,the stable isotope characteristics of precipitation are reshaped.Based on the data of six stations（Taiyuan,Yuanping,Jiexiu,Changzhi,Datong and Linfen）and eight stations（Shijiazhuang,Zhengzhou,Xi’an,Baotou,Yanchang,Luancheng,Ansai,Ordos,Weinan,Fengqiu and Hohhot）in Shanxi Province,the temporal and spatial characteristics of stable isotopes of precipitation in Shanxi Province are analyzed Based on the hysplit-4 model,the moisture sources track of representative stations in Shanxi Province is simulated,and the moisture sources area and air mass migration track are analyzed.The OLR technology is used to further explore the influence of moisture sources area change process on the isotopic characteristics of precipitation in Shanxi Province.The results show that the annual variation trend ofδ¹⁸O value of stations in Shanxi Province shows obvious spatial difference,with the characteristics of"high in summer and low in winter"in North Shanxi and"low in summer and high in winter"in South Shanxi;the characteristics of"high in summer and low in winter"in Taiyuan station and"low in summer and high in winter"in Jiexiu station in Central Shanxi.The distribution ofδ¹⁸O in Shanxi Province and its surrounding areas shows a decreasing trend from southeast to northwest as a whole.In the Western Shanxi Shaanxi Yellow River Valley and the western part of Luliang,there is a transitional feature of rapid decline.The results show that the slope and intercept of LMWL in Linfen station show typical monsoon climate characteristics in warm temperate zone,and Taiyuan station is more close to that in North Shanxi.On the whole,the temperature effect and precipitation effect have performance in each station.Datong station in the north of Shanxi Province is characterized by strong temperature effect,and precipitation effect only appears in summer;Linfen station in the south of Shanxi Province is characterized by precipitation effect,which is obvious in winter,but relatively short in relative time;the middle of Shanxi Province is characterized by significant transitional characteristics,Jiexiu station in the south of Shanxi Province and the isotopic fractionation model in the south of Shanxi Province In the north of Taiyuan station,the precipitation effect is the main one in summer half year,while the temperature effect is strong in winter half year.The moisture sources of the representative stations in Shanxi Province have obvious consistency,especially in spring,autumn and winter,the winter wind is the most important influencing factor of precipitation and isotope fractionation in Shanxi Province.In spring,Datong station and Taiyuan station are affected by the diversion of the plateau monsoon and the west wind;in summer,each station is dominated by the local circulating moisture,and the more obvious is the influence of the moisture from north to south.The change of moisture sources area is closely related to the characteristics of precipitation stable isotopes in Shanxi Province,which is mainly reflected in summer and half a year.This process is realized by the precipitation effect ofδ¹⁸O enhanced by marine moisture sources.The effect of water vapor source area change on precipitation stable isotopes in Shanxi Province has obvious regional difference,which is gradually weakened from south to north of Shanxi Province,while that in Central Shanxi Province is obvious The transition characteristics of.The results show that the evolution characteristics of precipitation isotopes in Shanxi Province,which is the edge of the East Asian monsoon region,sensitively reflect the change characteristics of ITCZ position and intensity in the moisture sources region.In order to reduce the atmospheric process,trace the source of water vapor,deeply understand the formation mechanism of regionalδ¹⁸O characteristics,and provide theoretical support for the scientific management and utilization of moisture sources,the prediction of meteorological changes,and promote the technical methods for the study of water cycle mechanism.It can also provide basic environmental isotope data for water resources investigation in Shanxi Province,and determine the formation mechanism ofδ¹⁸O characteristics in Shanxi Province.On this basis,it can deeply understand the atmospheric circulation model and water circulation mechanism,and accurately evaluate and predict the response of drought and flood disaster,extreme weather,climate change and runoff,so as to improve the rational utilization and scientific allocation of water resources in Shanxi Province Provide theoretical basis and prediction model.