摘要
大气水汽同位素实时监测为水循环和区域大气环流分析提供了新的定量化方法.依托雪龙号考察船,利用水同位素激光光谱仪(PICARRO L1102-i)完成了38°N^69°S海表大气水汽氢氧稳定同位素的观测,结合表层海水和GNIP降水同位素分析了多相水同位素纬向特征.结果表明:水汽、降水和表层海水同位素比率(δ18O,δD)随纬度呈明显的递变性规律,赤道最低,副热带升高,而在南极大陆外围高纬区域则急剧降低;过量氘(d-excess)变化与此相反,反映出副热带下沉气流对同位素富集影响以及高纬度极地气团经过洋面时过饱和分馏的剧烈变化.实测水汽同位素与LMDZ4-iso和ECHAM 5-w iso模型对比表明了模拟结果较好,根据模拟进一步分析了南极内陆Dome A水汽同位素反映的水汽源区.结果显示,除了中纬度印度洋海区之外,中低纬东太平洋海域也是冰盖内陆的重要水汽源区.
Atmospheric water vapor plays a crucial role in studies of the global water cycle and moisture transpor- tation. In this paper, based on the newly-developed cavity ring-down laser absorption spectroscopy analyzer- PICARRO L1102-i with special calibration protocols, real-time observations of afmosploric vapor stable isotopes above sea surface are carried out over the range of latitudes spanning 38° N to 69° S. Combined with sea surface water isotope and GNIP precipitation isotopic compositions, the latitudinal variations of multi-phase water isotope composition are analyzed, It shows in the southern hemisphere, δ^18O and δ^2H values decreases with increasing latitude, except a relative low value in the equatorial region. In particular, the data also shows an anomalously strong decreasing in vapor isotope composition and a corresponding increasing in d-excess in Antarctica coastal area. Comparing the observed water vapor isotopes with simulations by LMDZ4-iso and ECHAM5-wiso GCM, we found that there is a good agreement. Based on the simulation, vapor isotopes in Dome A in Antarctica were analyzed to study the water source areas of Antarctic ice sheet. The result shows that in addition to Indian Ocean in the mid-latitude, East Pacific Ocean in the mid-low latitude is also an important moisture source area of the interior of the ice sheet.
出处
《冰川冻土》
CSCD
北大核心
2014年第6期1440-1449,共10页
Journal of Glaciology and Geocryology
基金
国家重点基础研究发展计划(973计划)项目(2013CBA01804)
国家杰出青年基金项目(41425003)
国家自然科学基金项目(41206179)
国家海洋局极地科学考察专项项目(CHINARE2014-02-02)资助
关键词
大气水汽同位素
过量氘
水汽传输
DOME
A
atmospheric water vapor isotope
deuterium excess
moisture circulation
Dome A
