African Easterly Jet South: control, maintenance mechanisms and link with Southern subtropical waves
African Easterly Jet South: control, maintenance mechanisms and link with Southern subtropical waves
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非洲东风急流南流：控制、维护机制以及与南副热带波的联系
DOI：
10.1007/s00382-019-05072-w
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发表时间：
2019
期刊：
影响因子：
4.6
通讯作者：
Kuete G
中科院分区：
文献类型：
--
作者：
Kuete G
非洲东部南急流（AEJ-S）是中非对流层中环流的一个重要特征，已被确定为该地区对流的关键贡献者。本研究利用21年（1983-2003）ERA-Interim、NCEP2和MERRA2的再分析数据集，建立AEJ-S动态的相关机制。结果表明，9 - 11月，该气旋以旋转环流为主，并由在喀拉哈里地区形成的一个中层高压维持。由于这个高压系统在AEJ-S动力学中所起的作用，我们努力了解这个反气旋是如何发展的。研究表明，喀拉哈里地区对流层中高压是在9月至11月对流层下层干对流的影响下形成的。在这个高压的核心，反气旋环流被诱导并维持了位于高压北侧的AEJ-S。同时也揭示了AEJ-S动力学与副热带西风波之间的联系。研究表明，当波在南副热带上空放大时，它们改变了对流层下层的加热。根据波的相位，这会改变整个赤道地区的跨纬度温度梯度，从而调节喷流的强度。通过阐明控制AEJ-S的机制，这项研究工作有助于深入了解中非气候机制，并表明中非和南部非洲气候系统之间存在联系。这项研究工作还改善了有助于确定评估中非地区全球模式的适当指标的新机制的基础。
The African Easterly Jet South (AEJ-S) is an important feature of the central African mid tropospheric circulation and has been identified as a key contributor to convection over the region. This study uses 21-year (1983–2003) Reanalysis data sets of ERA-Interim, NCEP2 and MERRA2 to establish mechanisms related to AEJ-S dynamics. Results demonstrate that AEJ-S is dominated by rotational circulation and is maintained by a mid-level high that forms over the Kalahari region during September to November. Because of the role played by this high pressure system in the AEJ-S dynamics, an effort is made to understand how this anticyclone develops. We show that this mid-tropospheric high over the Kalahari region is established in response to lower tropospheric dry convection over the region from September to November. At the core of this high, anticyclonic circulation is induced and maintains AEJ-S located at the northern flank of the high. A link between AEJ-S dynamics and southern subtropical westerly waves is also revealed. It is shown that, when waves amplify over the southern subtropics, they modify lower tropospheric heating. Depending on the phase of the wave, this modifies the cross latitude temperature gradient throughout equatorial regions, therefore modulating the intensity of the jet. By clarifying the mechanisms that govern the AEJ-S, this research work contributes to insight into central Africa climate mechanisms and also suggests a link between central Africa and Southern Africa climate systems. This research work also improves the foundation of new mechanisms that help to identify suitable metrics for the evaluation of Global models over the Central Africa region.
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影响因子：
5.2
作者：
Ross Maidment;R. Allan;E. Black
通讯作者：
Ross Maidment;R. Allan;E. Black
北非夏季对流层中层环流的维持：撒哈拉高压和非洲东急流
DOI：
--
发表时间：
2005
期刊：
影响因子：
--
作者：
Tsing‐Chang Chen
通讯作者：
Tsing‐Chang Chen
耦合模型中环流对南部非洲降水的控制：安哥拉低压的作用
DOI：
10.1002/2016jd025736
发表时间：
2017
期刊：
Journal of Geophysical Research: Atmospheres
影响因子：
--
作者：
C. Munday;R. Washington
通讯作者：
R. Washington
非洲东风喷气机：结构和维护
影响因子：
4.9
作者：
Man;Li;C.;Wu;Max;J.;Suarez;Randy;D.;Koster;Philip;Pegion
通讯作者：
Pegion
DOI：
--
发表时间：
1993
期刊：
影响因子：
--
作者：
A. Wiin;Tsing‐Chang Chen
通讯作者：
Tsing‐Chang Chen