大高加索山南部大气降水氧同位素的气候意义  

Climatology interpretation of rainfall δ^18Op across the southern Greater Caucasus region

作　　者：王涛 李廷勇[1,2,3] 张键 WANG Tao;LI Tingyong;ZHANG Jian(Chongqing Key Laboratory of Karst Environment,School of Geographical Sciences,Southwest University,Chongqing 400715,China;State Cultivation Base of Eco-agriculture for Southwest Mountainous Land,Southwest University,Chongqing 408435,China;College of Tourism and Geography,Yunnan Normal University,Kunming,Yunnan 650050,China)

机构地区：[1]西南大学地理科学学院岩溶环境重庆市重点实验室,重庆400715 [2]西南大学西南山地生态循环农业国家级培育基地,重庆400715 [3]云南师范大学旅游与地理科学学院,昆明650050

出　　处：《中国岩溶》2020年第3期432-441,共10页Carsologica Sinica

基　　金：国家自然科学基金项目(41772170,42011530078);西南大学西南山地生态循环农业国家级培育基地项目(5330200076);中央高校基本科研业务费专项资金(XDJK2017A010)。

摘　　要：大高加索山脉位于黑海和里海之间,是欧洲与亚洲的分界线,该区域气候受到北大西洋涛动(North Atlantic Oscillation,NAO)的强烈影响。为了对该区域的大气降水δ^18O(δ^18OP)与NAO的关系有更加深入的认识,本文利用大高加索山以南6个全球降水同位素监测网(Global Network of Isotope in Precipitation,GNIP)站点的δ^18OP数据,分析该区域δ^18OP的季节变化规律,以及δ^18OP与温度和降水量等气象要素及大气环流之间的关系。得到以下主要认识:①在月时间尺度上,δ^18OP与月平均温度之间有着显著的正相关关系(p<0.01),表明该区域δ^18OP主要受当地温度控制,表现出“温度效应”。②北大西洋涛动通过改变西风的强度和位置从而影响δ^18OP的变化:当NAO呈现负相位时,此时西风输送较弱,使得来自地中海的富含18O的水汽能够达到大高加索山以南,该地区δ^18OP偏正。而当NAO正相位时,西风急流输送较强,从北大西洋穿越黑海带来更多的δ^18OP偏轻的降水。因此,NAO所导致的水汽输送路径的变化可能是影响大高加索山以南地区δ^18OP的重要因素,这一研究结果为利用该地区地质记录中的δ^18O记录来重建过去的NAO变化提供了前提。Located between the Black sea and Caspian sea,the Great Caucasus are the boundary between Europe and Asia,where the climate is strongly influenced by the north Atlantic Oscillation(NAO).Based on data of six stations of the Global Network of Isotope in Precipitation(GNIP)in the south of the Great Caucasus,we analyzed seasonal variations of δ^18Op as well as the relationship between δ^18Op and local temperature,precipitation,and atmospheric circulation.Results show that,(1)On the monthly time scale,there is a significant positive correlation between the average monthly temperature and δ^18Op(P<0.01),which indicates that δ^18Op in this region is mainly controlled by the local temperature,exhibiting a“temperature effect”.(2)The north Atlantic Oscillation(NAO)exerts influence on the variation of δ^18Op by changing the intensity and position of the westerly wind.When the NAO is in a negative phase,the westerly wind transport is weaker,making δ^18Op-rich from the Mediterranean able to arrive in the south of the Great Caucasus where the δ^18Op value showing positive.While when NAO is in a positive phase,the westerly wind conveys strongly,bringing more precipitation with lighter δ^18Op from the Black Sea.Therefore,the change of moisture transport path caused by NAO may be an important factor affecting the regional δ^18Op in the south of the Great Caucasus,which should be taken into consideration when reconstructing the past NAO changes by using the geological δ^18Op records in the region.

关 键 词：大气降水 Δ^18O 北大西洋涛动 水汽源地 大高加索山南部地区 

分 类 号：P426[天文地球—大气科学及气象学]