African Easterly Waves and Cyclonic Activity over the Eastern Atlantic: Composite and Case Studies
African Easterly Waves and Cyclonic Activity over the Eastern Atlantic: Composite and Case Studies
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DOI：
10.1155/2011/874292
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发表时间：
2011-10
影响因子：
1.1
通讯作者：
M. Camara;A. Diedhiou;A. Gaye
中科院分区：
文献类型：
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作者：
M. Camara;A. Diedhiou;A. Gaye
本研究旨在了解与大西洋气旋相关的非洲东波(发展中的非洲东波)和非发展中的非洲东波在非洲大陆和东大西洋的主要差异。一项统计研究表明，在西非海岸附近产生的命名气旋大多具有较长的生命周期，并且都与强烈的AEW有关。利用NCEP/NCAR再分析，对发展中AEW的特征进行了综合研究，并与非发展中AEW的特征进行了比较。发展中的AEW表现出最大的斜压和正压转换，这被认为是AEW增长的主要过程，表明这些AEW比非发展中的AEW更强。此外，发展中的AEW的特点是西非和大西洋存在相对较不稳定的环境。利用雷达探测资料的个例研究表明，与不发展的AEW个例相比，发展中的AEW与有利于深对流和随后的气旋生成的动力和热力学条件有关。
This study aims to understand the main differences over the African continent and the Eastern Atlantic Ocean between African Easterly Waves (AEWs) associated with Atlantic cyclones (developing AEWs) and non-developing AEWs. A statistical study showed that most of the named cyclones generated near the West African coast have a long lifecycle and all are associated with intense AEWs. Using NCEP/NCAR reanalyses, a composite study of the characteristics of developing AEWs is carried out and compared to those of non-developing AEWs. Developing AEWs exhibit the greatest baroclinic and barotropic conversions which are known to be the main processes involved in AEWs growth suggesting that these AEWs are stronger than the non-developing ones. Moreover, the developing AEWs are characterized by the existence of a relatively more unstable environment over West Africa and the Atlantic Ocean. A case study using rawinsonde data showed that the developing AEW is associated with dynamic and thermodynamic conditions conducive for deep convection and subsequent cyclogenesis compared to the non-developing AEW case.