The response of tropical cyclone (TC) destructive potential to global warming is an open issue. A number of previous studies have ignored the effect of TC size change in the context of global warming, which resulted in a significant underestimation of the TC destructive potential. The lack of reliable and consistent historical data on TC size limits the confident estimation of the linkage between the observed trend in TC size and that in sea surface temperature (SST) under the background of global climate warming. A regional atmospheric model is used in the present study to investigate the response of TC size and TC destructive potential to increases in SST. The results show that a large-scale ocean warming can lead to not only TC intensification but also TC expansion. The TC size increase in response to the ocean warming is possibly attributed to the increase in atmospheric convective instability in the TC outer region below the middle troposphere, which facilitates the local development of grid-scale ascending motion, low-level convergence and the acceleration of tangential winds. The numerical results indicate that TCs will become stronger, larger, and unexpectedly more destructive under global warming.

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A high-resolution Weather Research and Forecasting (WRF) model is used to simulate inner-core thermodynamic (such as moist static energy) and dynamic secondary circulation structure evolutions associated with the rapid intensification (RI) of Super Typhoon Yutu (2007). The results show that the column-integrated moist static energy (MSE) and the secondary circulation strength are significantly correlated to the typhoon intensity change. A rapid increase of the MSE during the RI period is primarily attributed to inner core temperature increase, due to enhanced subsidence within the eye and strengthened convective heating along the eyewall. The column-integrated MSE budget analysis shows that its rapid increase during the RI is mainly caused by surface latent heat flux. A further diagnosis of the Sawyer–Eliassen equation shows that the rapid strengthening of the secondary circulation during RI results from both the radially expanding positive diabatic heating over the eyewall and the occurrence of a second heating center outside the eyewall. While the radially expanding eyewall heating contributes about 70% of the secondary circulation change, the outer heating contributes about 30%.