Interannual variability of H218O in precipitation over the Asian monsoon region
Interannual variability of H218O in precipitation over the Asian monsoon region
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DOI：
10.1029/2011jd015890
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发表时间：
2012-08-25
影响因子：
4.4
通讯作者：
Oki, Taikan
中科院分区：
文献类型：
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作者：
Ishizaki, Yasuhiro;Yoshimura, Kei;Oki, Taikan
水的稳定同位素组成已被用作古代用指标来重建亚洲季风区过去的气候，但在这一地区的降水中的水的同位素的变化的主要控制还没有定量的特点。因此，我们使用的大气环流模式，结合稳定的水同位素物理定量估计的相对贡献，在亚洲季风区降水下降的同位素变化。与以前的研究一样，我们确定了两个控制O-18（降水量）年际变化的主要因素。（定义为（Rsample/R-VSMOW-1）x 1000，其中R-VSMOW是维也纳标准平均海水中的O-18比率）及其与厄尔尼诺-南方涛动（ENSO）事件的相关性：观测点的降水量以及从源区输送过程中的蒸馏。两个敏感性实验表明，蒸馏过程中从源区的运输是占主导地位的控制因素，在曼谷，孟买和香港，当地降水量的贡献分别为27%，33%和25%，而蒸馏过程分别贡献了70%，60%和70%。同样，蒸馏过程占80%，82%和83%的观察到的差异，在三角洲O-18（降水量）之间的厄尔尼诺和拉尼娜年在这三个城市，分别。因此，在三个站的Δ O-18（precip）的年际变化主要反映了蒸馏过程中从源区输送，它也是由大尺度热带变率（ENSO）。
The stable isotopic composition of water has been used as a paleoproxy to reconstruct past climates over the Asian monsoon region, but the main controls on the variability of isotopes of water in precipitation have not been characterized quantitatively in this region. Therefore, we used an atmospheric general circulation model incorporating stable water isotope physics to quantitatively estimate the relative contributions to isotope variability in precipitation falling in the Asian monsoon region. As in previous research, we identified two primary factors controlling the interannual variability of delta O-18(precip) (defined as (Rsample/R-VSMOW - 1) x 1000, where R-VSMOW is the O-18 ratio in Vienna Standard Mean Ocean Water) and its correlation with El Nino-Southern Oscillation (ENSO) events: the amount of precipitation at the observation site, and distillation during transport from source regions. Two sensitivity experiments revealed that distillation during transport from source regions was the dominant controlling factor; at Bangkok, Bombay, and Hong Kong, the amount of local precipitation contributed 27%, 33%, and 25% while distillation processes contributed 70%, 60%, and 70%, respectively. Similarly, distillation processes accounted for 80%, 82%, and 83% of observed differences in delta O-18(precip) between El Nino and La Nina years at these three cities, respectively. Therefore, interannual variability of delta O-18(precip) at the three stations primarily reflects distillation during transport from source regions, and it is also governed by the large-scale tropical variability (ENSO).