Influence of the Tibetan Plateau and its northern margins on the mid-latitude Westerly Jet over Central Asia in summer
Influence of the Tibetan Plateau and its northern margins on the mid-latitude Westerly Jet over Central Asia in summer
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DOI：
10.1016/j.palaeo.2020.109611
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发表时间：
2020-04
期刊：
影响因子：
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通讯作者：
Y. Sha;X. Ren;Zhengguo Shi;P. Zhou;Xinzhou Li;Xiao-dong Liu
中科院分区：
文献类型：
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作者：
Y. Sha;X. Ren;Zhengguo Shi;P. Zhou;Xinzhou Li;Xiao-dong Liu
夏季对流层上层西风急流维持在中亚中纬度地区，其强度和移动与中亚干旱地区降水变化密切相关。然而，人们对新生代西风急流的变化知之甚少，尽管人们知道青藏高原在现代亚洲气候中起着至关重要的作用。利用数值试验研究了青藏高原及其北方边缘地形（帕米尔高原、天山山脉和蒙古高原）对夏季西风急流的影响。随着青藏高原的隆升，中纬度西风急流明显增强。急流中心向北移动约1°。西风急流的加强和移动主要是由于青藏高原隆升引起的强大气热源。随着帕米尔高原和天山山脉的加入，西风急流北方轴西风增强，而南方轴西风减弱，导致西风急流持续北移。与青藏高原的影响相似，帕米尔高原和天山山脉的加入使西风急流强度略有减弱，并出现异常非绝热加热。西风急流也减弱，但当蒙古高原隆升时，西风急流停止向北移动。这是持续向北变暖的结果。因此，新生代中纬西风急流经历了明显的变化，这与青藏高原、天山山脉和蒙古高原的逐步隆升导致夏季大气热源的发展有关。这可能影响了亚洲内陆的干旱和风尘的输送。
The upper-troposphere Westerly Jet is currently maintained in the mid-latitudes of Central Asia during summer, the strength and movement of which are closely related to the variations in precipitation in arid Central Asia. However, little is known about how this Westerly Jet has changed during the Cenozoic, although it is known that the Tibetan Plateau has a crucial role in the modern Asian climate. We conducted a set of numerical experiments to examine the effects of the Tibetan Plateau and the topography of its northern margins (the Pamir Plateau, the Tian Shan mountains and the Mongolian Plateau) on the Westerly Jet in summer. The mid-latitude Westerly Jet is significantly intensified with the uplift of the Tibetan Plateau. The center of the jet stream moves about 1° to the north. This strengthening and shift in the Westerly Jet are primarily due to the strong atmospheric heat source induced by the uplift of the Tibetan Plateau. With the inclusion of the Pamir Plateau and Tian Shan mountains, the Westerly winds in the northern axis of the jet are strengthened while the southern part is weakened, resulting in a continuous northward shift in the Westerly Jet stream. Similar to the effects of the Tibetan Plateau, anomalous diabatic heating appears with the inclusion of the Pamir Plateau and Tian Shan mountains and the intensity of the Westerly Jet is slightly weakened. The Westerly Jet is also weakened, but stops moving northward, when the Mongolian Plateau is uplifted. This is a result of continuous northward warming. The mid-latitude Westerly Jet therefore experienced distinct changes during the Cenozoic in association with the development of the atmospheric heat source in summer as a result of the stepwise uplift of the Tibetan Plateau, Tian Shan mountains and Mongolian Plateau. This may have influenced the aridity of the Asian interior and the transport of eolian dust.