桂西北喀斯特小流域降雨稳定氢氧同位素组成及影响因素  

Composition of stable hydrogen and oxygen isotopic of precipitation and its influencing factors in karst area,northwest Guangxi of China

作　　者：张君 陈洪松[1,2] 黄荣[1,2,3] ZHANG Jun;CHEN Hongsong;HUANG Rong(Key Laboratory of Agro-ecological Processes in Subtropical Region,Institute of Subtropical Agriculture,Chinese Academy of Sciences,Changsha 410125,China;Huanjiang Observation and Research Station for Karst Ecosystems,Chinese Academy of Sciences,Huanjiang 547100,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,长沙410125 [2]中国科学院环江喀斯特生态系统观测研究站,环江547100 [3]中国科学院大学,北京100049

出　　处：《生态学报》2022年第1期236-245,共10页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(41971048);广西自然科学基金创新研究团队项目(2018GXNSFGA281003)。

摘　　要：气候变化背景下,降雨稳定氢氧同位素的变化对以快速的地表⁃地下水文过程为主要特征的喀斯特生态水文研究有重要意义。以桂西北典型喀斯特峰丛洼地小流域为研究对象,测定2013年至2018年日尺度及2019年至2020年8场大雨或特大暴雨的雨水稳定氢氧同位素组成,分析降雨稳定氢氧同位素变化特征及其影响因素。结果表明,研究区夏半年以海洋性水汽为主,冬半年以干燥的大陆性气团为主,导致夏半年降水δD、δ^(18)O和氘盈余值显著(P<0.05)低于冬半年。降水的稳定氢氧同位素存在显著的反温度效应和雨量效应,即δ^(18)O值与温度呈显著(P<0.001)负相关,与降雨量呈显著(P<0.001)正相关。次降雨过程中,持续时间较长(>9.5 h)的降雨存在显著的(P<0.05)雨量效应,特大暴雨则不存在雨量效应,与大气或地理因素有关。研究区水汽来源及降水强度存在明显的时间差异,因此在开展喀斯特小流域生态水文过程研究时,需要关注降水稳定氢氧同位素组成在不同时间尺度上的变化特征。In the context of global climate change,the variation of stable hydrogen and oxygen isotopes during rainfall is of great significance to study of the rapid surface⁃to⁃subsurface hydrologic processes in karst areas.We measured the hydrogen⁃oxygen isotope composition of water samples during the inter⁃annual scale rainfall from 2013 to 2018 and eight typical rainfalls(heavy rain to extremely heavy rain)from 2019 to 2020 in the karst area of northwest Guangxi.We also analyzed the variation characteristics of hydrogen⁃oxygen isotope and its influencing factors.The results show that theδD,δ18O,and d⁃excess in the summer half⁃year is significant(P<0.05)lower than the winter half⁃year.Hydrogen and oxygen isotopes stable in precipitation have anti⁃temperature effect and rainfall effect,that is,δ18 O value has a significantly(P<0.001)negative linear relationship with temperature and a significantly(P<0.001)positive linear relationship with rainfall.In the process of rainfall,the rainfall effect was only observed in the long⁃duration(>9.5 h)rainfall events.Extremely heavy rain does not have a rainfall effect and is related to atmospheric or geographical factors.These results suggest that studies on eco⁃hydrological processes should focus on the various characteristics of stable hydrogen and oxygen isotopic compositions of precipitation at different time scales.

关 键 词：大气降雨 稳定氢氧同位素 水汽来源 HYPLIST轨迹模型 极端降雨 

分 类 号：P426.6[天文地球—大气科学及气象学]