A self-weakening mechanism for tropical cyclones

File Description SizeFormat 
a.pdfFile embargoed until 29 June 20187.72 MBAdobe PDF    Request a copy
Title: A self-weakening mechanism for tropical cyclones
Author(s): Corsaro, CM
Toumi, R
Item Type: Journal Article
Abstract: A mechanism leading to the self-weakening of tropical cyclones is proposed using the Weather and Research and Forecasting model. A comparison between an experiment with variable Coriolis parameter f and one on an f-plane shows that after the initial intensification the former is characterized by a smaller intensity. As opposed to the tropical cyclone on the f-plane, the one with variable f weakens significantly after reaching maturity. Analyses of the 3-D circulation show that the main reason for the weakening is dry intrusion in the mid-upper troposphere from the west. Once the dry intrusion reaches the inner vortex, strong downdrafts reduce the high equivalent potential temperature in the boundary layer inflow. The subsequent updrafts in the eyewall, characterized by lower equivalent potential temperature, are considerably reduced and, consequently, the secondary circulation weakens. Back-trajectories are used to determine the origin of the dry intrusion. It is found that the air parcels expelled from the storm deep convection into the outflow layer recirculate anticyclonically back into the vortex, causing a self-weakening of the tropical cyclone. A time span for the recirculation of at least 48 h allows the air parcels to sink substantially before reaching the vortex circulation. Some implications of the intrinsic nature of this process are briefly discussed.
Publication Date: 29-Jun-2017
Date of Acceptance: 26-Jun-2017
URI: http://hdl.handle.net/10044/1/49813
DOI: https://dx.doi.org/10.1002/qj.3109
ISSN: 1477-870X
Publisher: Wiley
Start Page: 2585
End Page: 2599
Journal / Book Title: Quaterly Journal of the Royal Meteological Society
Volume: 143
Issue: 707
Copyright Statement: This is the peer reviewed version of the following article: Corsaro, C. M. and Toumi, R. (2017), A self-weakening mechanism for tropical cyclones. Q.J.R. Meteorol. Soc, 143: 2585–2599, which has been published in final form at https://dx.doi.org/10.1002/qj.3109.  This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
Sponsor/Funder: Met Office
Funder's Grant Number: P100212
Keywords: Science & Technology
Physical Sciences
Meteorology & Atmospheric Sciences
tropical cyclone
beta effect
self-weakening
dry intrusion
recirculation
back-trajectories
VERTICAL WIND SHEAR
VORTEX ROSSBY-WAVES
SEA INTERACTION THEORY
PART I
BAROCLINIC VORTICES
INTENSITY CHANGES
DOPPLER RADAR
SPIRAL BANDS
BETA DRIFT
MEAN FLOW
0401 Atmospheric Sciences
0405 Oceanography
Meteorology & Atmospheric Sciences
Publication Status: Published
Embargo Date: 2018-06-29
Appears in Collections:Space and Atmospheric Physics
Physics
Faculty of Natural Sciences



Items in Spiral are protected by copyright, with all rights reserved, unless otherwise indicated.

Creative Commons