The impact of gradient wind imbalance on potential intensity of tropical cyclones in an unbalanced slab boundary layer model

Emanuel's theory of hurricane potential intensity (E-PI) makes use of this assumption, whereas more recent studies by Bryan and Rotunno demonstrate that the effect of unbalanced flow can result in maximum winds that are well in excess of E-PI (superintensity). The existence of supergradient winds has been verified in a slab boundary layer model developed by Smith.

Here, the authors apply the slab boundary layer model within the framework of classical E-PI theory to investigate the sensitivity of supergradient winds to the radius of maximum gradient wind (RMGW) and four nondimensional model parameters. The authors find that the Rossby number, the drag coefficient, and the modified Rankine decay parameter all have a considerable influence on the strength of the unbalanced flow. In contrast, the ratio of surface exchange coefficients has little noticeable effect on superintensity.