The azimuthally averaged boundary layer structure of a numerically simulated major hurricane

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Authors
Abarca, Sergio F.
Montgomery, Michael T.
McWilliams, James C.
Subjects
The hurricane’s inner core boundary layer is found to be nonlinear
There are departures from Ekman-like balance in the hurricane boundary layer
Azimuthally averaged hurricane boundary layer lacks shock-like structures
Advisors
Date of Issue
2015-08-14
Date
Publisher
AGU Publications
Language
Abstract
This work examines the azimuthally averaged boundary layer structure of a numerically simulated hurricane. We nominally define the hurricane boundary layer as the layer in which the effects of surface friction are associated with significant departures from gradient wind balance. The boundary layer in the intensifying primary and forming secondary eyewalls is found to be nonlinear. At large radii, exterior to the eyewalls, Ekman-like balance as traditionally defined, is found to hold true. Where significant departures from Ekman-like balance are found, the departures are characterized by large vertical advection of horizontal velocity through the depth of the boundary layer. Shock-like structures are not found to be prominent in the azimuthally averaged view of the vortex boundary layer, with the largest azimuthally averaged radial gradients of the radial and tangential velocities being on the order of only a few meters per second per kilometer. Also, in the radial regions of the eyewalls, at the height where the averaged tangential wind is a maximum, the radial advection of radial velocity is an order of magnitude smaller than the agradient force per unit mass. Some physical implications of these findings are discussed.
Type
Research Article
Description
The article of record as published may be found at http://dx.doi.org/10.1002/2015MS000457
The data used in this paper can be accessed by emailing the first author at sergio.abarca@noaa.gov
Series/Report No
Department
Meteorology
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
National Research Council (NRC) Research Associateship Program
Naval Postgraduate School
Funder
National Science Foundation Awards AGS 0733380
National Science Foundation Awards IAA-1313948
Format
13 p.
Citation
Abarca, S. F., M. T. Montgomery, and J. C. McWilliams (2015), The azimuthally averaged boundary layer structure of a numerically simulated major hurricane, J. Adv. Model. Earth Syst., 7, 1207–1219, doi:10.1002/ 2015MS000457
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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