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Title: Role of eyewall and rainband eddy forcing in tropical cyclone intensification
Abstract. While turbulence is commonly regarded as a flow featurepertaining to the planetary boundary layer (PBL), intense turbulent mixinggenerated by cloud processes also exists above the PBL in the eyewall andrainbands of a tropical cyclone (TC). The in-cloud turbulence above the PBLis intimately involved in the development of convective elements in theeyewall and rainbands and consists of a part of asymmetric eddy forcing forthe evolution of the primary and secondary circulations of a TC. In thisstudy, we show that the Hurricane Weather Research and Forecasting (HWRF)model, one of the operational models used for TC prediction, is unable togenerate appropriate sub-grid-scale (SGS) eddy forcing above the PBL due toa lack of consideration of intense turbulent mixing generated by the eyewalland rainband clouds. Incorporating an in-cloud turbulent-mixingparameterization in the vertical turbulent-mixing scheme notably improvesthe HWRF model's skills in predicting rapid changes in intensity for several pastmajor hurricanes. While the analyses show that the SGS eddy forcing abovethe PBL is only about one-fifth of the model-resolved eddy forcing, thesimulated TC vortex inner-core structure, secondary overturning circulation,and the model-resolved eddy forcing exhibit a substantial dependence on theparameterized SGS eddy processes. The results highlight the importance ofeyewall and rainband SGS eddy forcing to numerical prediction of TCintensification, including rapid intensification at the current resolutionof operational models.  more » « less
Award ID(s):
1822128
PAR ID:
10141603
Author(s) / Creator(s):
; ; ; ; ; ; ;
Date Published:
Journal Name:
Atmospheric Chemistry and Physics
Volume:
19
Issue:
22
ISSN:
1680-7324
Page Range / eLocation ID:
14289 to 14310
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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