气候变化领域集成服务门户(CCPortal): Influence of the QBO on tropical convection and its impact on tropical cyclone activity over the western North Pacific

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DOI	10.1007/s00382-021-05731-x
	Influence of the QBO on tropical convection and its impact on tropical cyclone activity over the western North Pacific
	Huangfu J.; Tang Y.; Ma T.; Chen W.; Wang L.
发表日期	2021
ISSN	0930-7575
起始页码	123
结束页码	138
英文摘要	On the basis of 70 hPa zonal wind (U70)-defined quasi-biennial oscillation (QBO) events, after removing the El Niño–Southern Oscillation (ENSO) signal, the present study investigates the process by which the QBO modulates tropospheric circulation and convection during summer (between July and October), when tropical cyclone (TC) activities enter their peak period. Concurrent with the western phase of the QBO (QBOW), significant tripole pattern modulations over the tropical Indo-Pacific Ocean are regressed onto the residual part of U70 after removing the ENSO signal, with enhanced convection observed over its central branch (0°–10°N, 120°E–180°) and the inactive convection branches located to both sides. A ventilation opening-like effect is exerted on the monsoon trough, which is shifted southward under the QBOW phase. According to the QBO-associated changes in the circulations over the tropical western North Pacific (WNP), equatorial environments (with low-level relative vorticity, high-level divergence, tropospheric vertical wind shear (VWS), and midlevel humidity) tend to be favorable for TC genesis. Consequently, the off-equatorial TC tracks show a significantly decreased occurrence frequency in the northern monsoon trough region. The present study provides a summary sketch showing the QBO-tropospheric circulation modulation process. Considering that the westerly or weak easterly is observed over the upper central Pacific (CP), QBOW phase-associated weak VWS can induce anomalous upward motion at equatorial latitudes, together with the upwelling between the equatorial westerly and off-equatorial easterly, leading to an enlarged convective window over the CP. Affected by the prevailing easterly within the tropics, the actual pumping shifts westward over the tropical WNP. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Quasi-biennial oscillation; Tropical convection; Tropical cyclone activity; Western North Pacific
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/183454
作者单位	Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
推荐引用方式 GB/T 7714	Huangfu J.,Tang Y.,Ma T.,et al. Influence of the QBO on tropical convection and its impact on tropical cyclone activity over the western North Pacific[J],2021.
APA	Huangfu J.,Tang Y.,Ma T.,Chen W.,&Wang L..(2021).Influence of the QBO on tropical convection and its impact on tropical cyclone activity over the western North Pacific.Climate Dynamics.
MLA	Huangfu J.,et al."Influence of the QBO on tropical convection and its impact on tropical cyclone activity over the western North Pacific".Climate Dynamics (2021).