The basic wind characteristics of idealized hurricanes of different intensity levels

Abstract

In the current study, we conducted four idealized hurricane simulation cases to investigate the basic wind characteristics of hurricanes at different sea surface temperatures. First, the relationship of the minimum of sea surface pressure and the maximum of time-averaged wind speed shows good agreement with observational data and theoretical considerations. Then, the tangential, radial, and vertical wind field are analyzed, both the value and the height of the maximum tangential wind increase with increasing sea surface temperature. The peak value and the height of radial inflow also increase with sea surface temperature increases. An important feature is for the depth of the inflow layer, which always increases for weak hurricanes and beginning increases then decreases for intense hurricanes locates from hurricane eye to three times radius of maximum wind, this can also be seen in hurricane observation data. More importantly, this is the first study that found it begins to increase then becomes steady for medium-strength hurricanes. Furthermore, extreme updrafts are found for intense hurricanes, while not for weak and medium-strength hurricanes, and this also shows good agreement between the observational and simulation data, which is related to coherent subkilometer-scale vortices. Also, the average surface inflow angle is −22.1°, similar to −22.6° ± 2.2° and −23° that are obtained in other studies, and the distribution of surface inflow angle displays good agreement with previous studies. The relationship of tangential velocity and radial velocity is similar to the shape of a tilted infinity symbol. Finally, by analyzing the fluctuating wind characteristics, a 200 m grid size is sufficient except for the weak hurricane, which requires a 62 m grid size for turbulence structures. From the relationship of mean and fluctuating wind characteristics, the hurricane simulation results of different intensity levels converged for 185 m and 62 m grid size.