The relationship between characteristics of stable isotopes and moisture sources of extreme precipitation in the transection of 38° north latitude in North China
The transection of 38° north latitude in North China is an important agricultural zone,and precipitation is the main source of groundwater supply in the region.In recent years,the increasing frequency of extreme precipitation has changed the way groundwater is replenished.This study is based on the collection of precipitation samples from one mountainous station(Taihangshan)and two plain stations(Luancheng and Nanpi)in the transection of 38° north latitude in North China from January 2016 to December 2021.Correlation analysis and HYSPLIT model were used to reveal the relationship between the δ2H and δ18O of the extreme heavy precipitation in the study area and spatiotemporal distribution characteristics and the moisture source.The results show that the stable isotopes of hydrogen and oxygen in precipitation show a trend of depletion between years in high water years.During the year,they show a trend of enrichment in the rainy season and depletion in the dry season,with extreme precipitation isotopes being the most depleted(-105.7‰ to-39.1‰,and-14.6‰ to-5.7‰,respectively).The isotope relationship of atmospheric precipitation indicates that Luancheng Station located in the piedmont plain has the smallest slope and intercept,and the strongest evaporation.The results of the HYSPLIT model indicate that the extreme heavy precipitation water vapor at Taihangshan Station mainly comes from the southeast monsoon water vapor and southwest monsoon water vapor,while that at Luancheng and Nanpi stations mainly comes from the westerly water vapor and southeast monsoon water vapor.The increase in the proportion of southwest monsoon water vapor(16.67％-58.33％)is the main reason for the isotope depletion of extreme heavy precipitation in mountainous areas compared to plain areas.The difference in moisture sources is the main reason why the δ18O value of the extreme heavy rainfall event on July 21,2021 in the study area is higher than that of the precipitation event on July 19,2016.The above understanding can provide a basis for the study of atmospheric circulation and hydrological cycle processes in the transection of 38° north latitude in North China.
the transection of 38° north latitude in North Chinaextreme precipitationhydrogen and oxygen stable isotopesHYSPLIT modelmoisture source
万方数据
维普
