Study On Stable Isotope Characteristics Of Meteoric Precipitation And Water Vapor Source In Shijiazhuang

Global climate and environmental change and its impact are one of the most important issues that the international community pays close attention to and is increasingly related to human survival and social development.As a natural tracer to record and reconstruct paleoclimate changes,precipitation stable isotopes can respond to climate and environment changes sensitively and stably.Through its continuous monitoring,the water vapor source of precipitation can be traced and the atmospheric process can be reversed,and the mechanism and law of climate change can be summarized,so as to better serve the production and life of human beings.The collected samples of 168 precipitation events from August 2013 to December2018 in Shijiazhuang were tested,and the relationship between the collected samples and the corresponding temperature and precipitation was analyzed.At the same time,the HYSPLIT model was used to analyze the variation characteristics of hydrogen-oxygen stable isotopes at precipitation event scale,seasonal scale and interannual scale,and the characteristics of hydrogen-oxygen stable isotopes and water vapor source of precipitation in Shijiazhuang were preliminarily discussed and analyzed.According to the study,the variation range of?¹⁸O in Shijiazhuang is-21.20‰⁴.07‰,and the variation range of?D is-155.22‰²6.92‰,which is highly coincident with the variation range of stable isotopic value of atmospheric precipitation in China.The change in season scale is the highest in spring,the lower in winter and the similar in summer and autumn.The equation of the precipitation line in Shijiazhuang is:?D=6.92?¹⁸O+2.82?R2=0.91,P<0.05?.The slope and intercept are both smaller than the global precipitation line and China's precipitation line,reflecting its relatively dry climate characteristics.The variation range of d value is-23.14‰to 39.39‰,of which the variation range of summer half year?Apil-September?is-19.24‰to 39.39‰,and the variation range of winter half year?October-March?is-23.14‰to 27.74‰,showing the overall seasonal characteristics of"low summer and high winter",which matches the evaporation conditions of different precipitation and water vapor source areas in summer and winter festival in China.At the scale of precipitation events,?¹⁸O had a certain correlation with temperature,but the correlation was weak:?¹⁸O=0.17t-9.18?R2=0.13,P<0.01?.?¹⁸O also had a weak negative correlation with precipitation:?¹⁸O=-0.05 p-5.52?R2=0.05,P<0.01?.By contrast,the influence of temperature on precipitation stable isotopes in Shijiazhuang is greater than that of precipitation,and so is the interannual scale.The regression analysis on a seasonal scale shows that the temperature effect and precipitation effect of the summer half year and the winter half year are not very significant,among which the correlation between the summer half year?¹⁸O and precipitation is more obvious,and the correlation between the winter half year?¹⁸O and temperature is more obvious.Using HYSPLIT model to track after each precipitation,combined with the feature of the water vapor sources Shijiazhuang precipitation types can be divided into 7types including summer monsoon precipitation,the inland and westerly precipitation,the summer monsoon and inland mixed precipitation,the combination of non-summer monsoon oceanic precipitation and inland precipitation,inland and local mixed precipitation and non-summer monsoon oceanic precipitation,and the hydrogen-oxygen stable isotopes,meteoric precipitation lines and d values of each type of precipitation are also discussed.In addition,the proportion of westerly and inland precipitation in Shijiazhuang is larger than that of summer monsoon precipitation,which may be related to the movement of north boundary of summer monsoon in north China.