The Critical Combined Effects of Intraseasonal Oscillations and Tropical Equatorial Rossby Waves on the Tropical Cyclone Genesis Over Bay of Bengal During May

IF 4.6 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters Pub Date : 2025-10-04 DOI:10.1029/2025gl117438

Ze Meng, Hui Yu, Baosheng Li, Jianhuang Qin, Rui Jin, Lei Zhou, Renhe Zhang

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引用次数: 0

Abstract

Tropical cyclone genesis (TCG) over the Bay of Bengal (BoB) in May can lead to severe meteorological hazards, underscoring the need to identify physical mechanisms with early‐warning potentials. This study quantifies over 90% of TCG events are influenced by northward‐propagating intraseasonal oscillations (ISOs), which transports enhanced low‐level vorticity, reduced vertical wind shear, mid‐level moisture and warm sea surface temperature from the equator to BoB. Most TCG events occur within 20 days after the equatorial intraseasonal convections, highlighting the latter as one early‐warning indicator. Diagnostics reveal the biweekly westward‐propagating equatorial Rossby (ER) waves help channel energy from the intraseasonal envelope into developing tropical disturbances for 86% cyclogenesis. These westward Rossby waves appear over Indochina‐South China Sea 5–10 days before TCG, also serving as a potential TCG indicator. By identifying the synergistic impact of ISOs and ER waves, this study offers scientific guidance for improving subseasonal prediction in this high‐risk region.

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月间季内振荡和热带赤道罗斯比波对孟加拉湾热带气旋形成的关键联合作用

5月孟加拉湾（BoB）上空的热带气旋形成（TCG）可能导致严重的气象灾害，强调有必要确定具有预警潜力的物理机制。该研究量化了超过90%的TCG事件受到向北传播的季内振荡（isoos）的影响，isoos将低层涡度增强、垂直风切变减少、中层湿度和温暖的海表温度从赤道输送到赤道附近。大多数TCG事件发生在赤道季节内对流之后的20天内，强调后者是一个预警指标。诊断显示，每两周向西传播的赤道罗斯比（ER）波有助于将能量从季内包络输送到发展中的热带扰动中，导致86%的气旋形成。这些向西的罗斯比波在TCG前5-10天出现在印度支那-南中国海上空，也可以作为潜在的TCG指标。通过确定ISOs和ER波的协同影响，本研究为改善该高风险地区的亚季节预报提供了科学指导。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Geophysical Research Letters 地学-地球科学综合

CiteScore

9.00

自引率

9.60%

发文量

1588

审稿时长

2.2 months

期刊介绍： Geophysical Research Letters (GRL) publishes high-impact, innovative, and timely research on major scientific advances in all the major geoscience disciplines. Papers are communications-length articles and should have broad and immediate implications in their discipline or across the geosciences. GRLmaintains the fastest turn-around of all high-impact publications in the geosciences and works closely with authors to ensure broad visibility of top papers.