渭河流域秋雨异常氢氧稳定同位素特征及其水汽来源  

Anomalous stable hydrogen⁃oxygen isotope characteristics and water vapor sources of autumn precipitation in the Weihe River basin,Northwest China

作　　者：韦昊延 陆彦玮 李敏[2] 李培月[1] 程文青 司炳成 WEI Haoyan;LU Yanwei;LI Min;LI Peiyue;CHENG Wenqing;SI Bingcheng(Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of Minis-try of Education,School of Water and Environment,Chang’an University,Xi’an 710054,China;Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education,Northwest A&F Uni-versity,Yangling 712100,Shaanxi,China;Department of Soil Science,University of Saskatoon,SK S7N5A8,Canada)

机构地区：[1]长安大学水利与环境学院旱区地下水文与生态效应教育部重点实验室,西安710054 [2]西北农林科技大学旱区农业水土工程教育部重点实验室,陕西杨凌712100 [3]萨斯喀彻温大学土壤学系,加拿大萨斯卡通市S7N5A8

出　　处：《应用生态学报》2023年第7期1737-1744,共8页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(42107068,41877017);中国博士后科学基金面上项目(2021M692744)资助。

摘　　要：秋雨极端变化对渭河流域生态环境影响巨大。本研究根据2015—2021年在渭河流域腹地杨凌区采集的117个秋季降水样本和同期相关气象资料,开展秋雨异常氢氧稳定同位素组成及其水汽来源的研究。结果表明:1)近年来研究区秋雨极端变化频繁,根据秋雨指数(ARI)可分为秋季极端多雨年(HAP,2021年)、普通降雨年(GAP,2015—2017,2019—2020年)和极端少雨年(LAP,2018年);2)不同类型秋雨氢氧稳定同位素组成差异明显,其中,δ^(2)H、δ^(18)O值呈现出LAP年>GAP年>HAP年的变化趋势,而d⁃excess值和秋雨降水线斜率、截距值的变化趋势与之相反。进一步分析不同类型秋雨同位素的影响因素和水汽来源发现,出现秋雨异常的主要原因并非当地气象要素,而可能是厄尔尼诺⁃南方涛动事件和印度洋偶极子事件,其分别解释了99%和93%的秋雨同位素异常变化。这些海气耦合现象影响海洋性气团水汽向西北内陆的输送强度,进而决定了秋雨雨量和氢氧稳定同位素组成。本研究结果有助于提高对华西秋雨异常的认识,为区域水文模型的构建提供了基础资料和理论支撑,可以更好地服务于水资源管理决策和防灾减灾。The extreme changes in autumn rain have significant impacts on the ecological environment of Weihe River basin.Based on 117 autumn rain samples and corresponding meteorological data from 2015 to 2021 at Yangling located in the middle of Weihe River basin,we investigated the stable hydrogen and oxygen isotope composition and water vapor sources of precipitation.The results showed that,(1)extreme changes in autumn rainfall in the study area occurred frequently in recent years,which could be divided into extreme⁃high autumn precipitation year(HAP,2021),general autumn precipitation year(GAP,2015-2017,2019-2020)and extreme⁃low autumn pre⁃cipitation year(LAP,2018)based on the autumn rain index(ARI);(2)the stable isotopes of different types of precipitation differed significantly,with a pattern of LAP>GAP>HAP for bothδ^(2)H andδ^(18)O values.the variations of d⁃excess values and the slopes and intercepts of the meteoric water lines of autumn rain showed opposite trends.The main factor controlling autumn rain anomaly was not the local meteorological parameters,but the El Nino⁃Southern Oscillation and the Indian Ocean dipole events,which could explain 99%and 93%of the autumn rain isotopic variations,respectively.These coupling phenomena affected water vapor transport intensity of the marine air mass to the northwest inland,which determined autumn rainfall amount and the stable hydrogen⁃oxygen isotope composition.Our results would be helpful for improving the understanding of autumn rain anomalies in West China,and provide basic data and theoretical support for regional hydrological model building,would thereby better serve water resources management and disaster prevention and reduction.

关 键 词：极端秋雨 氢氧稳定同位素 水汽来源 渭河流域 

分 类 号：P426[天文地球—大气科学及气象学]