Equatorward shift of the South Asian high in response to anthropogenic forcing
Equatorward shift of the South Asian high in response to anthropogenic forcing
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DOI：
10.1007/s00704-014-1095-1
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发表时间：
2014-05
影响因子：
3.4
通讯作者：
X. Qu;G. Huang;Kaiming Hu;S. Xie;Yan Du;Xiao‐Tong Zheng;Lin Liu
中科院分区：
文献类型：
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作者：
X. Qu;G. Huang;Kaiming Hu;S. Xie;Yan Du;Xiao‐Tong Zheng;Lin Liu
南亚高压（SAH）是对流层上部的一个巨大的反气旋。它影响气候和微量成分和污染物的分布。本研究记录了全球变暖下SAH和降水的变化，以及变化之间可能的联系，基于17个耦合模型相互比较项目第5阶段（CMIP 5）模型模拟。CMIP 5历史模拟合理地再现了对流层环流（包括南亚高压），降水和水分。在全球变暖的情况下，超过75%的CMIP 5模型预测了SAH的南移。在气候南亚高压南部反气旋环流较强的模式中，南移更为显著。降水响应表现出对比鲜明的功能：在赤道印度洋东南部为负，而在热带北方印度洋、孟加拉湾和赤道西太平洋为正。线性斜压模式（LBM）的结果表明，孟加拉湾和赤道西太平洋区域降水的变化是南亚高压南移的主要原因。此外，印度洋-太平洋地区的降水和地面风场响应耦合良好。一方面，地面风场异常通过改变海温和湿度来影响降水响应;另一方面，区域降水变化释放的凝结加热维持地面风响应。
The South Asian high (SAH) is a huge anticyclone in the upper troposphere. It influences the climate and the distribution of trace constituents and pollutants. The present study documents the change in the SAH and precipitation under global warming, as well as the possible link between the changes, based on 17 Coupled Model Intercomparison Project Phase 5 (CMIP5) model simulations. The CMIP5 historical simulation reproduces reasonably the tropospheric circulation (including the SAH), precipitation, and moisture. Under global warming, more than 75 % of the CMIP5 models project a southward shift of the SAH. The southward shift is more significant in the models with stronger anticyclonic circulation in the south part of the climatological SAH. The precipitation response displays a contrasting feature: negative over the southeastern equatorial Indian Ocean (IO) and positive over the tropical northern IO, the Bay of Bengal, and the equatorial western Pacific. The results of a linear baroclinic model (LBM) show that the regional rainfall changes over the Bay of Bengal and the equatorial western Pacific have a main contribution to the southward shift of the SAH. In addition, the precipitation and the surface wind responses over the Indo-Pacific region are well coupled. On one hand, the surface wind anomaly affects the rainfall response through altering the SST and moisture. On the other hand, the condensational heating released by regional rainfall changes sustains the surface wind response.