Major changes in East Asian climate in the mid-Pliocene: Triggered by the uplift of the Tibetan Plateau or global cooling?
Major changes in East Asian climate in the mid-Pliocene: Triggered by the uplift of the Tibetan Plateau or global cooling?
复制标题
上新世中期东亚气候重大变化：是青藏高原隆升引发还是全球变冷引发？
DOI：
10.1016/j.jseaes.2012.10.009
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发表时间：
2013-06-05
影响因子：
3
通讯作者：
Guo, Zhengtang
中科院分区：
文献类型：
--
作者：
Ge, Junyi;Dai, Ying;Guo, Zhengtang
上新世中期以来，东亚气候发生了重大变化。一种观点认为，这一时期青藏高原的显著抬升可能是东亚季风强度和亚洲内陆酸化的巨大变化的原因，而其他一些作者则将这些变化归因于全球持续变冷和北极冰盖的快速增长。上新世中期东亚气候变化的主导因素是什么，至今仍有争议。对黄土高原东部西峰红粘土序列和西秦岭西河上新统黄土-土壤序列的粒度、（CaO* + Na 2 O + MgO）/TiO 2比值、Na/Ka比值和粉尘积累速率等气候指标进行了分析。结果表明，自上新世中期以来，大陆内部的干旱和冬季风环流都有所加强，而东亚夏季风则表现出减弱而不是加强的趋势。这些变化也得到了东亚各地区其他多代理记录的支持。以往的数值模拟研究表明，青藏高原的隆升将同时增强大陆尺度夏季风和冬季风的强度以及中亚的干旱。因此，东亚上新世中期的气候变化不太可能是高原隆升的反应。相反，我们最近的模拟结果支持这样一种观点，即持续的冷却可能会加强内陆的干旱和冬季风的强度，但削弱了东亚的夏季风。(c)2012爱思唯尔有限公司保留所有权利。
Since the mid-Pliocene, East Asian climates have experienced significant changes. One view suggests that significant uplift of the Tibetan Plateau during this period could have been responsible for these dramatic changes in the strength of the East Asian monsoon and for Asian interior acidification, while some other authors attribute these changes to the ongoing global cooling and rapid growth of the Arctic ice-sheet. Up to the present, which factor dominates the major changes of East Asian climate in the mid-Pliocene is still a contentious issue. This study presents an analysis of several climate proxies including grain-size, (CaO* + Na2O + MgO)/TiO2 ratio, Na/Ka ratio and dust accumulation rates of the Xifeng Red Clay sequence in the eastern Chinese Loess Plateau and the Xihe Pliocene loess-soil sequence in West Qinling. They reveal that aridity in the continental interior and winter monsoon circulation both intensified, whereas the East Asian summer monsoon showed a weakening rather than intensifying trend since the mid-Pliocene. These changes are also supported by the other multi-proxy records from various regions in East Asia. Previous numerical modeling studies have demonstrated that uplift of the Tibetan Plateau would have simultaneously enhanced continental-scale summer and winter monsoon strength as well as central Asian aridity. The mid-Pliocene climate changes in East Asia are therefore unlikely to be a response to Plateau uplift. On the contrary, our recent modeling results give support to the view that ongoing cooling could have intensified both the aridity of the interior and the strength of the winter monsoon, but weakened the summer monsoon in East Asia. (c) 2012 Elsevier Ltd. All rights reserved.