摘要
稳定性氢氧同位素可以作为示踪剂来判断大气降水的水汽来源.本研究选择柴达木盆地南部的格尔木和东北部的德令哈两个区域,在分析这两个地区2010年6~9月降水同位素组成特征、时间变化以及降水中δD与δ18O关系的基础上,探讨柴达木盆地降水的水汽来源.结果表明:1格尔木和德令哈地区6~9月大气降水线分别为,格尔木:δD=7.840δ18O-4.566(R2=0.918,P<0.001),德令哈:δD=7.833δ18O+8.606(R2=0.986,P<0.001).两地区6~9月大气降水线的斜率和截距均低于全球大气降水线,而格尔木地区的截距仅为-4.566,反映出格尔木极其干旱的气候特点.2格尔木降水的δ18O在7月初较高,表现出一定的重同位素富集;在7月中下旬至9月初,δ18O较低;9月中下旬更低.德令哈降水的δ18O在6~8月相对较高,9月中下旬较低.3格尔木和德令哈地区水汽来源有一定的差异,格尔木地区可能是西南季风能够到达青藏高原的北部边界,德令哈地区水汽来源主要为局地蒸发.
Stable hydrogen and oxygen isotopes can be used as a tracer to analyze water vapor sources of atmospheric precipitation. We choose Golmud and Delingha as our study areas,Golmud locates in the south of Qaidam basin,and Delingha locates in the northeast.Based on the analysis of monthly change of hydrogen and oxygen isotopic compositions of precipitation during June to September of2010,and the relationship between δD and δ18O in precipitation,we investigated the water vapor sources of precipitation in eastern Qaidam basin. The results show that: 1 meteoric water line between June to September in Golmud is: δD = 7. 840 δ18O-4. 566( R2= 0. 918,P < 0. 001),and in Delingha is: δD = 7. 833 δ18O + 8. 606( R2= 0. 986,P < 0. 001). The slopes and intercepts of meteoric water line between June to September in both Golmud and Delingha are lower than the global average,and the intercept in Golmud is only-4. 566,which indicates the extremely arid climate condition. 2 the δ18O content of precipitation is much higher in Golmud in early July,it shows the enrichment of some heavier isotopes. However,the δ18O content of precipitation becomes lower from late July to early September,especially for the late September. The δ18O content of precipitation in Delingha is higher in June to August than that in late September. 3 the water vapor sources of precipitation in Golmud and Delingha are different,Golmud area is the northern border of Qinghai-Tibet Plateau where the southwest monsoon can reach,and the southwest monsoon brings water vapors of precipitation,but the water vapors of precipitation in Delingha are mainly from local evaporation.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2015年第8期2784-2790,共7页
Environmental Science
基金
国家自然科学基金项目(40971118)
关键词
柴达木盆地
氢氧同位素
水汽来源
大气降水线
过量氘
Qaidam Basin
hydrogen and oxygen isotopes
water vapor sources
meteoric water line
deuterium excess
