Tornadoes in Southeast South America: Mesoscale to Planetary-scale Environments

IF 2.8 3区 地球科学 Q3 METEOROLOGY & ATMOSPHERIC SCIENCES
Daniel Veloso-Aguila, Kristen L. Rasmussen, Eric D. Maloney
{"title":"Tornadoes in Southeast South America: Mesoscale to Planetary-scale Environments","authors":"Daniel Veloso-Aguila, Kristen L. Rasmussen, Eric D. Maloney","doi":"10.1175/mwr-d-22-0248.1","DOIUrl":null,"url":null,"abstract":"Abstract A multiscale analysis of the environment supporting tornadoes in Southeast South America (SESA) was conducted based on a self-constructed database of 74 reports. Composites of environmental and convective parameters from ERA5 were generated relative to tornado events. The distribution of the reported tornadoes maximizes over the Argentine plains, while events are rare close to the Andes and south of Sierras de Córdoba. Events are relatively common in all seasons except in winter. Proximity environment evolution shows enhanced instability, deep-layer vertical wind shear, storm-relative helicity, reduced convective inhibition, and a lowered lifting condensation level before or during the development of tornadic storms in SESA. No consistent signal in low-level wind shear is seen during tornado occurrence. However, a curved hodograph with counterclockwise rotation is present. The Significant Tornado Parameter (STP) is also maximized prior to tornadogenesis, most strongly associated with enhanced CAPE. Differences in the convective environment between tornadoes in SESA and the U.S. Great Plains are discussed. On the synoptic scale, tornado events are associated with a strong anomalous trough crossing the southern Andes that triggers lee cyclogenesis, subsequently enhancing the South American Low-Level Jet (SALLJ) that increases moisture advection to support deep convection. This synoptic trough also enhances vertical shear that, along with enhanced instability, sustains organized convection capable of producing tornadic storms. At planetary scales, the tornadic environment is modulated by Rossby wave trains that appear to be forced by convection near northern Australia. Madden-Julian oscillation phase 3 preferentially occurs one to two weeks ahead of tornado occurrence.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":2.8000,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Monthly Weather Review","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1175/mwr-d-22-0248.1","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"METEOROLOGY & ATMOSPHERIC SCIENCES","Score":null,"Total":0}
引用次数: 0

Abstract

Abstract A multiscale analysis of the environment supporting tornadoes in Southeast South America (SESA) was conducted based on a self-constructed database of 74 reports. Composites of environmental and convective parameters from ERA5 were generated relative to tornado events. The distribution of the reported tornadoes maximizes over the Argentine plains, while events are rare close to the Andes and south of Sierras de Córdoba. Events are relatively common in all seasons except in winter. Proximity environment evolution shows enhanced instability, deep-layer vertical wind shear, storm-relative helicity, reduced convective inhibition, and a lowered lifting condensation level before or during the development of tornadic storms in SESA. No consistent signal in low-level wind shear is seen during tornado occurrence. However, a curved hodograph with counterclockwise rotation is present. The Significant Tornado Parameter (STP) is also maximized prior to tornadogenesis, most strongly associated with enhanced CAPE. Differences in the convective environment between tornadoes in SESA and the U.S. Great Plains are discussed. On the synoptic scale, tornado events are associated with a strong anomalous trough crossing the southern Andes that triggers lee cyclogenesis, subsequently enhancing the South American Low-Level Jet (SALLJ) that increases moisture advection to support deep convection. This synoptic trough also enhances vertical shear that, along with enhanced instability, sustains organized convection capable of producing tornadic storms. At planetary scales, the tornadic environment is modulated by Rossby wave trains that appear to be forced by convection near northern Australia. Madden-Julian oscillation phase 3 preferentially occurs one to two weeks ahead of tornado occurrence.
南美洲东南部的龙卷风:中尺度到行星尺度的环境
摘要基于自建的74份报告数据库,对南美东南部龙卷风形成环境进行了多尺度分析。生成了与龙卷风事件相关的ERA5环境参数和对流参数的复合。报告的龙卷风分布在阿根廷平原上最大,而靠近安第斯山脉和Córdoba山脉南部的事件很少发生。除了冬天,其他季节的活动都比较普遍。邻近环境演化表现出不稳定性增强、深层垂直风切变增强、风暴相对螺旋度增强、对流抑制减弱、上升凝结水平降低等特征。在龙卷风发生期间,低层风切变没有一致的信号。然而,一个弯曲的hodograph逆时针旋转存在。重要龙卷风参数(STP)也在龙卷风形成前达到最大值,与CAPE增强密切相关。讨论了SESA和美国大平原地区龙卷风对流环境的差异。在天气尺度上,龙卷风事件与一个穿越安第斯山脉南部的强异常槽有关,该槽触发了背风气旋形成,随后增强了南美低空急流(SALLJ),增加了水汽平流以支持深层对流。这个天气槽也增强了垂直切变,与增强的不稳定性一起,维持有组织的对流,能够产生龙卷风风暴。在行星尺度上,龙卷风环境是由罗斯比波列调制的,这种波列似乎是由澳大利亚北部附近的对流造成的。马登-朱利安振荡阶段3优先发生在龙卷风发生前一至两周。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
Monthly Weather Review
Monthly Weather Review 地学-气象与大气科学
CiteScore
6.40
自引率
12.50%
发文量
186
审稿时长
3-6 weeks
期刊介绍: Monthly Weather Review (MWR) (ISSN: 0027-0644; eISSN: 1520-0493) publishes research relevant to the analysis and prediction of observed atmospheric circulations and physics, including technique development, data assimilation, model validation, and relevant case studies. This research includes numerical and data assimilation techniques that apply to the atmosphere and/or ocean environments. MWR also addresses phenomena having seasonal and subseasonal time scales.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信