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

Tang, Jie; Zhang, Jun A.; Chan, Pakwai; Hon, Kaikwong; Lei, Xiaotu; Wang, Yuan

doi:10.1038/s41598-021-97766-7

i

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

2021
By Tang, Jie ; Zhang, Jun A. ; Chan, Pakwai ; ...

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Journal Title:

Scientific Reports
Personal Author:

Tang, Jie ; Zhang, Jun A. ; Chan, Pakwai ; Hon, Kaikwong ; Lei, Xiaotu ; Wang, Yuan
NOAA Program & Office:

OAR (Oceanic and Atmospheric Research) ; CIMAS (Cooperative Institute for Marine and Atmospheric Studies) ; AOML (Atlantic Oceanographic and Meteorological Laboratory)
Description:

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.
Keywords:

Aircraft Observations Atmospheric Dynamics Boundary Layer Cyclones Fluid Dynamics Aircraft Observations Atmospheric Dynamics Boundary Layer Fluid Dynamics
Source:

Sci Rep 11, 18771
DOI:

https://doi.org/10.1038/s41598-021-97766-7
Document Type:

Journal Article
Funding:

Grant no. NA19OAR0220186
Rights Information:

CC BY
Compliance:

Submitted
Main Document Checksum:

urn:sha256:d47311b64c8180cb5a99cfb03594f25060db30a663a72afc99fc8ec965f59bdd
Download URL:

https://repository.library.noaa.gov/view/noaa/32704/noaa_32704_DS1.pdf
File Type:

[PDF - 3.47 MB ]

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