The West African Monsoon Dynamics. Part III: The Quasi-Biweekly Zonal Dipole
The West African Monsoon Dynamics. Part III: The Quasi-Biweekly Zonal Dipole
复制标题
西非季风动力学。
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
G. Kiladis
中科院分区：
文献类型：
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作者：
F. Mounier;S. Janicot;G. Kiladis
摘要本文研究了北方夏季非洲季风季节内主要对流模态的形成机制，即准双周纬向偶极子（QBZD）。QBZD的主要特征是准静止的纬向对流偶极子，其尺度大于西非季风域，其两极中心沿着几内亚海岸，在赤道大西洋的30°和60°W之间。QBZD动力学过程内南极-非洲域的一些详细的检查。QBZD在近赤道纬向平面上有一个与沃克型环流相关的偶极型。它既受赤道大气动力学控制，通过在两极之间向东传播的开尔文波状扰动，也受非洲大陆表面过程控制，引起西非海岸表面温度、表面压力和低空纬向风的综合波动。当对流处于最小值时…
Abstract This paper presents an investigation of the mechanisms giving rise to the main intraseasonal mode of convection in the African monsoon during northern summer, here identified as the quasi-biweekly zonal dipole (QBZD). The QBZD is primarily characterized by a quasi-stationary zonal dipole of convection whose dimension is larger than the West African monsoon domain, with its two poles centered along the Guinean coast and between 30° and 60°W in the equatorial Atlantic. The QBZD dynamical processes within the Atlantic–Africa domain are examined in some detail. The QBZD has a dipole pattern associated with a Walker-type circulation in the near-equatorial zonal plane. It is controlled both by equatorial atmospheric dynamics through a Kelvin wave–like disturbance propagating eastward between its two poles and by land surface processes over Africa, inducing combined fluctuations in surface temperatures, surface pressure, and low-level zonal winds off the coast of West Africa. When convection is at a min...