Mid Miocene Indian Monsoon Dynamics

20多亿人的生计依赖于亚洲季风降雨，即使使用最先进的海洋-大气环流耦合模型，也仍然难以预测。详细了解季风在不同边界条件下的行为，例如一个温暖的世界，大陆冰盖较少，对这些模型至关重要。我们还需要知道季风系统如何以及何时开始增强，随后如何发展，以及它如何因各种潜在影响而变化，包括全球气候变化，山脉建设和海洋门户的打开和关闭。现代东亚和印度季风系统增强的时间是有争议的，一些记录（如阿拉伯海上升流）表明初始增强发生在大约700 - 800万年前，而其他记录（如黄土形成）则表明它早在大约2200万年前，甚至更早。模拟研究表明，季风的增强与西藏的隆升直接相关，直接联系了全球气候和构造。在这里，我们建议使用新的高质量的中新世沉积物岩心从孟加拉湾（实验。353)重建印度季风在中新世时期（2300万至560万年前）的演变。我们将研究该地区大陆风化与轨道时间尺度上全球气候的耦合。使用高分辨率的代用记录垂直表面海洋混合季风风，季风雨引起的盐度变化和微量金属的风化通量的海洋，这项研究的结果将显着提高我们的理解亚洲季风的发展，并将有助于更准确地模拟季风系统。

The livelihoods of more than 2 billion people depend on the Asian monsoon rains, which are still difficult to predict even with the most advanced coupled ocean-atmosphere general circulation models. A detailed understanding how the monsoon behaves under different boundary conditions such as a warmer world with less continental ice cover is vital for these models. We also need to know how and when the monsoon system first intensified, how it subsequently developed and how it has varied in response to various potential influences including global climate changes, mountain building and opening and closing of oceanic gateways. The timing of the intensification of the modern East Asian and Indian monsoon systems is controversial, with some records (e.g. Arabian Sea upwelling) indicating initial intensification occurred ~7–8 million years ago, whereas others (e.g. Loess formation) suggest it was as early as ~22 million years ago, or even earlier. Modeling studies have suggested that the intensification of the monsoon was directly related to the uplift of Tibet, directly linking global climate and tectonics. Here we propose to use new high quality Miocene sediment cores from the Bay of Bengal (Exp. 353) to reconstruct the evolution of the Indian monsoon through the Miocene period (23 to 5.6 million years ago). We will investigate the coupling of continental weathering in the region with global climate on orbital time scales. Using high resolution proxy records of vertical surface ocean mixing by monsoon winds, salinity changes caused by monsoon rains and the weathering flux of trace metals to the ocean, the results of this study will significantly improve our understanding of the development of the Asian monsoon and will contribute to a more accurate modeling of the monsoon system.