Publication Date
4-1-2021
Document Type
Article
Publication Title
Atmosphere
Volume
12
Issue
4
DOI
10.3390/atmos12040492
Abstract
The prediction of rapid intensification (RI) in tropical cyclones (TCs) is a challenging problem. In this study, the RI process and factors contributing to it are compared for two TCs: an axis-symmetric case (Hurricane Irma, 2017) and an asymmetric case (Hurricane Michael, 2018). Both Irma and Michael became major hurricanes that made significant impacts in the United States. The Hurricane Weather Research and Forecasting (HWRF) Model was used to examine the connection between RI with forcing from the large-scale environment and the subsequent evolution of TC structure and convection. The observed large-scale environment was reasonably reproduced by HWRF forecasts. Hurricane Irma rapidly intensified in an environment with weak-to-moderate vertical wind shear (VWS), typically favorable for RI, leading to the symmetric development of vortical convective clouds in the cyclonic, vorticity-rich environment. Conversely, Hurricane Michael rapidly intensified in an environment of strong VWS, typically unfavorable for RI, leading to major asymmetries in the development of vortical convective clouds. The tangential wind momentum budget was analyzed for these two hurricanes to identify similarities and differences in the pathways to RI. Results suggest that eddy transport terms associated with convective processes positively contributed to vortex spin up in the early stages of RI and inhibited spin up in the later stages of RI in both TCs. In the early stages of RI, the mean transport terms exhibited notable differences in these TCs; they dominated the spin-up process in Irma and were of secondary importance to the spin-up process in Michael. Favorable aspects of the environment surrounding Michael appeared to aid in the RI process despite hostile VWS.
Funding Number
16SEC4810006
Funding Sponsor
National Oceanic and Atmospheric Administration
Keywords
Eddy vorticity fluxes, Hurricanes rapid intensification, HWRF, Momentum budget
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Department
Meteorology and Climate Science
Recommended Citation
Alrick Green, Sundararaman G. Gopalakrishnan, Ghassan J. Alaka, and Sen Chiao. "Understanding the role of mean and eddy momentum transport in the rapid intensification of Hurricane Irma (2017) and Hurricane Michael (2018)" Atmosphere (2021). https://doi.org/10.3390/atmos12040492
