A direct aircraft observation of helical rolls in the tropical cyclone boundary layer

Abstract Helical rolls are known to play a significant role in modulating both the mean and turbulence structure of the atmospheric boundary layer in tropical cyclones. However, in-situ measurements of these rolls have been limited due to safety restrictions. This study presents analyses of data col...

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Autores principales: Jie Tang, Jun A. Zhang, Pakwai Chan, Kaikwong Hon, Xiaotu Lei, Yuan Wang
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Lenguaje:EN
Publicado: Nature Portfolio 2021
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Acceso en línea:https://doaj.org/article/356a6cd18a004485a78f361118f2d241
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spelling oai:doaj.org-article:356a6cd18a004485a78f361118f2d2412021-12-02T17:27:03ZA direct aircraft observation of helical rolls in the tropical cyclone boundary layer10.1038/s41598-021-97766-72045-2322https://doaj.org/article/356a6cd18a004485a78f361118f2d2412021-09-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-97766-7https://doaj.org/toc/2045-2322Abstract Helical rolls are known to play a significant role in modulating both the mean and turbulence structure of the atmospheric boundary layer in tropical cyclones. However, in-situ measurements of these rolls have been limited due to safety restrictions. This study presents analyses of data collected by an aircraft operated by the Hong Kong Observatory in Typhoon Kalmaegi (1415) and Typhoon Nida (1604). Examination of the flight-level data at ~ 600 m altitude confirmed the existence of sub-kilometer-scale rolls. These rolls were mostly observed in the outer-core region. Turbulent momentum fluxes were computed using the eddy correlation method. The averaged momentum flux of flight legs with rolls was found to be ~ 2.5 times that of legs without rolls at a similar wind speed range. This result suggests that rolls could significantly modulate turbulent transfer in the tropical cyclone boundary layer. This roll effect on turbulent fluxes should be considered in the planetary boundary layer parameterization schemes of numerical models simulating and forecasting tropical cyclones.Jie TangJun A. ZhangPakwai ChanKaikwong HonXiaotu LeiYuan WangNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-9 (2021)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Jie Tang
Jun A. Zhang
Pakwai Chan
Kaikwong Hon
Xiaotu Lei
Yuan Wang
A direct aircraft observation of helical rolls in the tropical cyclone boundary layer
description Abstract Helical rolls are known to play a significant role in modulating both the mean and turbulence structure of the atmospheric boundary layer in tropical cyclones. However, in-situ measurements of these rolls have been limited due to safety restrictions. This study presents analyses of data collected by an aircraft operated by the Hong Kong Observatory in Typhoon Kalmaegi (1415) and Typhoon Nida (1604). Examination of the flight-level data at ~ 600 m altitude confirmed the existence of sub-kilometer-scale rolls. These rolls were mostly observed in the outer-core region. Turbulent momentum fluxes were computed using the eddy correlation method. The averaged momentum flux of flight legs with rolls was found to be ~ 2.5 times that of legs without rolls at a similar wind speed range. This result suggests that rolls could significantly modulate turbulent transfer in the tropical cyclone boundary layer. This roll effect on turbulent fluxes should be considered in the planetary boundary layer parameterization schemes of numerical models simulating and forecasting tropical cyclones.
format article
author Jie Tang
Jun A. Zhang
Pakwai Chan
Kaikwong Hon
Xiaotu Lei
Yuan Wang
author_facet Jie Tang
Jun A. Zhang
Pakwai Chan
Kaikwong Hon
Xiaotu Lei
Yuan Wang
author_sort Jie Tang
title A direct aircraft observation of helical rolls in the tropical cyclone boundary layer
title_short A direct aircraft observation of helical rolls in the tropical cyclone boundary layer
title_full A direct aircraft observation of helical rolls in the tropical cyclone boundary layer
title_fullStr A direct aircraft observation of helical rolls in the tropical cyclone boundary layer
title_full_unstemmed A direct aircraft observation of helical rolls in the tropical cyclone boundary layer
title_sort direct aircraft observation of helical rolls in the tropical cyclone boundary layer
publisher Nature Portfolio
publishDate 2021
url https://doaj.org/article/356a6cd18a004485a78f361118f2d241
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