Impact of Mongolian Plateau versus Tibetan Plateau on the westerly jet over North Pacific Ocean
Impact of Mongolian Plateau versus Tibetan Plateau on the westerly jet over North Pacific Ocean
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DOI：
10.1007/s00382-014-2217-2
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发表时间：
2015-06
期刊：
影响因子：
4.6
通讯作者：
Zhengguo Shi;Xiao-dong Liu;Yimin Liu;Y. Sha;Tingting Xu
中科院分区：
文献类型：
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作者：
Zhengguo Shi;Xiao-dong Liu;Yimin Liu;Y. Sha;Tingting Xu
长期以来，人们一直认为山脉在现代气候的形成中发挥着重要作用。特别是在亚太区，青藏高原的存在维持了定常行星波型，加强了北太平洋西风急流。然而，蒙古高原（MP）的潜在作用往往被忽视，在这些研究。利用大气环流模式，我们发现，尽管MP的规模较小，但它对行星尺度环流和副热带西风急流有很大的影响。MP放大了对流层中上层的纬向热梯度，从而加强了急流，这主要是由其高纬度位置促成的。通过阻挡西风，MP迫使其北方分支进一步北上，这使得冷空气在背风面向南渗透，并加强了东亚槽。相比之下，TP本身的影响并没有预期的那么大。因此，我们不应该简单地将所有的山脉引起的气候变化归因于TP的隆起，因为其他较小的地形也可能非常重要。
Mountains have long been considered to play an important role in the formation of modern climate. Particularly in the Asia-Pacific sector, the existence of Tibetan Plateau (TP) is believed to maintain the stationary planetary wave patterns and to intensify the westerly jet over North Pacific. However, the potential role of Mongolian Plateau (MP) has often been neglected in these studies. With an atmospheric general circulation model, we show that the MP, despite its smaller size, exerts a great influence on the planetary-scale circulation and the subtropical westerly jet. The MP amplifies the meridional thermal gradient at the mid-upper troposphere and thus strengthens the jet, which is primarily facilitated by its high-latitude location. By blocking westerly winds, the MP forces their northern branch further northward, which allows the southward penetration of cold air at the lee side, and intensifies the East Asian trough. In contrast, the impact of the TP itself is not as large as expected. Hence, one should not simply ascribe all the mountain-induced climate change to the TP uplift, because other smaller topography might be also very important.