Intraseasonal Modulation of Synoptic-Scale Disturbances and Tropical Cyclone Genesis in the Eastern North Pacific
Intraseasonal Modulation of Synoptic-Scale Disturbances and Tropical Cyclone Genesis in the Eastern North Pacific
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DOI：
10.1175/jcli-d-13-00399.1
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发表时间：
2014-07
影响因子：
4.9
通讯作者：
E. Crosbie;Y. Serra
中科院分区：
文献类型：
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作者：
E. Crosbie;Y. Serra
摘要利用北太平洋东部海盆区域模式研究了麦登-朱利安涛动（MJO）对天气尺度波的影响。天气尺度波是热带气旋和热带气旋形成的重要前兆。利用区域模式和存档最佳轨迹数据的组合，对MJO进行了旋流发生频率的评估。与中性条件相比，区域模式的统计数据与数据比较好，表明MJO在抑制阶段主要阻止环流形成，而在活跃阶段主要增强环流形成。云量和涡旋动能的天气尺度变率以及涡旋路径统计分析表明，在正压能量和对流层水分可用性的支持下，MJO活跃期波浪强度持续增强。垂直风切变对气旋的发展至关重要，它也表现出与MJO相位相关的强变率，但与此相反。
AbstractThe influence of the Madden–Julian oscillation (MJO) on synoptic-scale waves, important precursors to tropical cyclones and tropical cyclogenesis, is investigated using a regional model of the eastern North Pacific basin. Cyclogenesis frequency is evaluated with respect to the MJO using a combination of the regional model and the archive best-track data. The statistics of the regional model compare well to the data and suggest that the MJO predominantly deters cyclogenesis during the suppressed phase rather than enhances it during the active phase when compared to neutral conditions. Synoptic-scale variability of cloudiness and eddy kinetic energy and analysis of vortex track statistics show a consistent enhancement of wave strength during the active phases of the MJO supported by both barotropic energetics and tropospheric moisture availability. Vertical wind shear, of critical importance to cyclone development, also exhibits strong variability associated with the phase of the MJO but, contrary t...