粤西云浮市大气降水δ^(18)O与水汽来源的关系  

Correlation of δ^(18)O in Precipitation and Moisture Sources at Yunfu,Western Guangdong Province,China

作　　者：郑琰明[1] 钟巍[1] 彭晓莹[1] 薛积彬[1] 赵引娟[1] 马巧红[1] 蔡颖[1] 

机构地区：[1]华南师范大学地理科学学院,广州510631

出　　处：《环境科学》2009年第3期637-643,共7页Environmental Science

基　　金：国家自然科学基金项目(40671189);广东省自然科学基金项目(06025042,8151063101000044);教育部霍英东基金项目(91021)

摘　　要：2005-04-05~2006-04-01期间在粤西云浮市采集了59次具有显著天气过程的大气降水样品,并进行了稳定氧同位素测试,结果显示此期间云浮市大气降水中δ18O值波动于-12.47‰^-0.18‰之间,平均值为-4.91‰;夏秋季(5~9月)的δ18O值相对偏低,多数在-10.00‰^-5.00‰,平均-6.30‰;冬春季(11月~次年4月)的δ18O值相对偏高,多数在-3.00‰^-1.00‰,平均-2.20‰.这些δ18O值与它们相应的气温、水汽压(e)呈较为显著负相关,相关系数(R)均达-0.60,而与降水量的负相关性较差,相关系数(R)为-0.33.与大致同时期的广州降水中δ18O月平均值相比,云浮降水中δ18O呈相对低值,可能与云浮市受到了较强的西南季风叠加影响有关.后推气流轨迹的结果表明,这些大气降水1δ8O值在前汛期(4~6月)、后汛期(7~9月)和非汛期(10月~次年4月)中的变化很大程度上受不同水汽来源决定,表明降水δ18O值在一定程度上具有指示水汽来源的作用:δ18O值偏高的大气降水其水汽可能主要来源于西太平洋的副热带海区(包括我国南海海域)的变性热带太平洋暖气团;而δ18O值偏低的大气降水其水汽则来源于印度洋和孟加拉湾的变性热带海洋气团.Fifty-nine samples of atmospheric precipitation were collected at Yunfu, Western Guangdong province during the period of April 5, 2005 to April 1, 2006 and their oxygen isotopic compositions were analyzed. Results show that δ^18O values range from -12.47‰ to -0.18‰ with an average of -4.91‰; the δ^18O values of summer and autumn （from May to September） are relatively lower, ranging from - 10.00‰ to -5.00‰ with an average of -6.30‰; the δ^18O values of winter and spring （from October to next April） are relatively higher, ranging from - 3.00‰ to - 1.00‰ with an average of - 2.20‰. These δ^18O values have relatively marked negative correlation with the corresponding temperatures and water vapour pressure and their coefficients are both - 0.60 ; but they have bad negative correlation with the precipitation amount, the coefficient is - 0.33. Comparing with the monthly ~ls O value of Guangzhou atmospheric precipitation, those of Yunfu City is relatively lower, maybe the reason is that Yunfu City is influenced by stronger South-West Asian Monsoon. The results of HYSPLIT back trajectory analysis indicated that the differences of ~s O values are determined by different water vapour sources during the pre- rainy season （from April to June）, post-rainy season （from July to September） and non-rainy season （from October to next April）, so the δ^18O values can be considered as an indicator of denoting their water vapour sources, relatively higher δ^18O values denote the water vapour sources are denaturalized tropical hot air mass located in the subtropical sea areas （including the South China Sea）, western Pacific Ocean; relatively lower δ^18O values indicate denaturalized tropical hot air mass from the India Ocean and Bengal Gulf.

关 键 词：大气降水 氧同位素 水汽来源 云浮市 

分 类 号：X142[环境科学与工程—环境科学] X143