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A self-weakening mechanism for tropical cyclones
Title: | A self-weakening mechanism for tropical cyclones |
Authors: | 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. |
Issue 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 |
Publication Status: | Published |
Appears in Collections: | Space and Atmospheric Physics Physics Faculty of Natural Sciences |