Potential Intensification Rate of Tropical Cyclones in a Simplified Energetically Based Dynamical System Model: An Observational Analysis

Abstract

In a recent study by Wang et al. that introduced a dynamical efficiency to the intensification potential of a tropical cyclone (TC) system, a simplified energetically based dynamical system (EBDS) model was shown to be able to capture the intensity dependence of TC potential intensification rate (PIR) in both idealized numerical simulations and observations. Although the EBDS model can capture the intensity dependence of TC intensification as in observations, a detailed evaluation has not yet been done. This study provides an evaluation of the EBDS model in reproducing the intensity-dependent feature of the observed TC PIR based on the best track data for TCs over the North Atlantic and central, eastern, and western North Pacific during 1982–2019. Results show that the theoretical PIR estimated by the EBDS model can capture basic features of the observed PIR reasonably well. The TC PIR in the best track data increases with increasing relative TC intensity [intensity normalized by its corresponding maximum potential intensity (MPI)] and reaches a maximum at an intermediate relative intensity around 0.6, and then decreases with increasing relative intensity to zero as the TC approaches its MPI, as in idealized numerical simulations. Results also show that the PIR for a given relative intensity increases with the increasing MPI and thus increasing sea surface temperature, which is also consistent with the theoretical PIR implied by the EBDS model. In addition, future directions to include environmental effects and make the EBDS model applicable to predict intensity change of real TCs are also discussed.