气候变化领域集成服务门户(CCPortal): Iba: The First Pure Tropical Cyclogenesis Over the Western South Atlantic Ocean

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DOI	10.1029/2020JD033431
	Iba: The First Pure Tropical Cyclogenesis Over the Western South Atlantic Ocean
	Reboita M.S.; Crespo N.M.; Dutra L.M.M.; Silva B.A.; Capucin B.C.; da Rocha R.P.
发表日期	2021
ISSN	2169897X
卷号	126 期号:1
英文摘要	In March 2019, the tropical western South Atlantic Ocean (∼16.5°S) registered the first pure tropical cyclogenesis since the beginning of the satellite era, which the Brazilian Navy named Iba. This study presents a description of the synoptic features and meteorological mechanisms contributing to Iba's initial cyclonic vorticity as well as the anomalous synoptic patterns linked to this unprecedented tropical cyclogenesis. Moreover, a general description of Iba's lifecycle is provided. The genesis of Iba was as a pure tropical cyclone (00:00 UTC on March 22), and it underwent subtropical (18:00 UTC on March 25) and extratropical (06:00 UTC on March 29) transitions. Anomalies for a 5-day period prior to the genesis relative to the March climatology show environmental features appropriate for tropical cyclogenesis: (a) vertical wind shear in the 850–200 hPa lower than 10 m s−1, (b) intense initial cyclonic relative vorticity at 925 hPa (−10 × 10−5 s−1), (c) latent and sensible heat fluxes near the climatological values (∼150 W m−2), (d) warmer sea surface temperature (+2°C), and (e) relative humidity at 700 hPa 20% higher than the climatology. These features were associated with an anomalous wave pattern at 500 hPa, resembling a blocking structure over the southeastern South Pacific Ocean, and an anticyclonic circulation at upper levels over southeastern Brazil. This environment propitiated a weak vertical wind shear and convective cloud organization. Near the surface, the horizontal wind shear between the postfrontal southwesterly winds and the northeasterly winds of the South Atlantic subtropical anticyclone helped to generate Iba's initial cyclonic vorticity. © 2020. American Geophysical Union. All Rights Reserved.
英文关键词	convection; CPS; Genesis Potential Index; horizontal wind shear; Iba; South Atlantic Ocean; synoptic analysis; tropical cyclogenesis
语种	英语
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/185546
作者单位	Instituto de Recursos Naturais, IRN, Universidade Federal de Itajubá, Itajubá, MG, Brazil; Departamento de Ciências Atmosféricas, Universidade de São Paulo, São Paulo, SP, Brazil
推荐引用方式 GB/T 7714	Reboita M.S.,Crespo N.M.,Dutra L.M.M.,et al. Iba: The First Pure Tropical Cyclogenesis Over the Western South Atlantic Ocean[J],2021,126(1).
APA	Reboita M.S.,Crespo N.M.,Dutra L.M.M.,Silva B.A.,Capucin B.C.,&da Rocha R.P..(2021).Iba: The First Pure Tropical Cyclogenesis Over the Western South Atlantic Ocean.Journal of Geophysical Research: Atmospheres,126(1).
MLA	Reboita M.S.,et al."Iba: The First Pure Tropical Cyclogenesis Over the Western South Atlantic Ocean".Journal of Geophysical Research: Atmospheres 126.1(2021).