Hurricane formation in diabatic Ekman turbulence
Hurricane formation in diabatic Ekman turbulence
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DOI：
10.1002/qj.405
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发表时间：
2008-05
影响因子：
8.9
通讯作者：
D. Schecter;T. Dunkerton
中科院分区：
文献类型：
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作者：
D. Schecter;T. Dunkerton
本文研究了热带对流层三层模式中飓风从混沌涡旋运动中的出现，该模式包括积云对流和海气相互作用的基本参数化。混沌流被称为非绝热埃克曼湍流（DET），以强调积云对流和埃克曼泵对其行为至关重要。DET中飓风形成所需的时间在广泛的海面温度，热带纬度和湿熵和动量的表面交换系数范围内进行了检查。平均趋势是合理的，但对于给定的一组参数，起源时间可以随初始湍流的细微变化而显著变化。此外，飓风并不总是形成的。如果热带低气压发展成飓风，其过程是高度不对称的。增强涉及到切变流不稳定性、中涡旋的产生和基本环流的收缩。尽管演变复杂，但强化率在很大程度上与准线性稳定性分析的预期一致。成熟的飓风和它们的波动性质的属性进行了讨论的背景下的模型。版权所有© 2009皇家气象学会
This article investigates the emergence of hurricanes from chaotic swirling motions in a three‐layer model of the tropical troposphere that includes basic parametrizations of cumulus convection and air‐‐sea interaction. The chaotic flow is referred to as diabatic Ekman turbulence (DET), in order to emphasize that cumulus convection and Ekman pumping are critical to its behaviour. The time required for hurricane formation in DET is examined over a broad range of sea‐surface temperatures, tropical latitudes and surface exchange coefficients for moist entropy and momentum. The mean trends are sensible, but for a given set of parameters, the genesis time can vary significantly with subtle changes to the initial turbulence. Moreover, hurricanes do not always form. In the event that a tropical depression develops into a hurricane, the process is highly asymmetric. Intensification involves a shear‐flow instability, the production of mesovortices and contraction of the basic circulation. Despite the complex evolution, the intensification rate is largely consistent with the expectations of a quasi‐linear stability analysis. Properties of mature hurricanes and the nature of their fluctuations are discussed in the context of the model. Copyright © 2009 Royal Meteorological Society