Modeling δ18O in tropical precipitation and the surface ocean for present-day climate
Modeling δ18O in tropical precipitation and the surface ocean for present-day climate
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DOI：
10.1029/2004jd005611
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发表时间：
2006-03-07
影响因子：
4.4
通讯作者：
Noone, D
中科院分区：
文献类型：
--
作者：
Brown, J;Simmonds, I;Noone, D
[1]墨尔本大学大气环流模式与稳定的水同位素示踪剂被用来检查同位素比值的变化，降水和表层海洋在热带地区的今天（1950-1999年）的气候。表面海洋同位素比率的模拟交互式使用一维方案，再现所观察到的热带同位素的空间分布和季节性和年际变化的关键特征。模拟热带降水同位素比值的季节和年际变化与降水量的变化密切相关，与以前的同位素模拟研究一致。模拟的降水和表层海水的同位素比值响应厄尔尼诺-南方涛动（ENSO），虽然空间格局的ENSO和季风同位素响应不同于观测，因为模拟的热带气候的偏见。该模型捕获的降水同位素比在热带安第斯山脉的年际变化的依赖当地的温度和降水的变化和亚马逊流域的水分平衡，但未能重现一个显着的ENSO降水或同位素信号在这一地区。模拟的降水同位素比值与当地降水量显着相关，但不与当地或区域温度在青藏高原冰芯站点的年际时间尺度上，不同意这些冰芯记录作为温度代理的解释。表层海洋同位素比率用于计算模拟的“珊瑚”同位素比率，并将其与现代珊瑚记录进行比较，再现观测到的年际变化，其中降水模拟良好。
[1] The Melbourne University atmospheric general circulation model with stable water isotope tracers is used to examine the variability of isotopic ratios of precipitation and the surface ocean in the tropics for present-day (1950-1999) climate. Surface ocean isotopic ratios are simulated interactively using a one-dimensional scheme that reproduces key features of the observed tropical isotopic spatial distribution and seasonal and interannual variability. The seasonal and interannual variability of modeled isotopic ratios of tropical precipitation is strongly associated with changes in precipitation amount, in agreement with previous isotopic modeling studies. Modeled isotopic ratios of both precipitation and surface ocean water respond to El Nino-Southern Oscillation (ENSO), although the spatial patterns of ENSO and monsoon isotopic responses differ from observations because of biases in the simulated tropical climate. The model captures the dependence of the interannual variability of precipitation isotopic ratios over the tropical Andes on local temperature and precipitation variability and moisture balance over the Amazon basin but fails to reproduce a significant ENSO precipitation or isotope signal over this region. Modeled precipitation isotopic ratios are significantly correlated with local precipitation amount but not with local or regional temperature at Tibetan Plateau ice core sites on interannual timescales, in disagreement with the interpretation of these ice core records as temperature proxies. Surface ocean isotopic ratios are used to calculate modeled "coral,'' isotopic ratios which are compared with modern coral records, reproducing observed interannual variability where precipitation is well simulated.