Contribution of Dissipative Heating to the Intensity Dependence of Tropical Cyclone Intensification

Abstract

Previous studies have demonstrated the contribution of dissipative heating (DH) to the maximum potential intensity (MPI) of tropical cyclones (TCs). Since DH is a function of near-surface wind speed and thus TC intensity, a natural question arises as to whether DH contributes to the intensity-dependence of TC potential intensification rate (PIR). To address this issue, an attempt has been made to include DH in a recently developed time-dependent theory of TC intensification. With this addition, the theory predicts a shift of the maximum PIR towards the higher intensity side, which is consistent with the intensity-dependence of TC intensification rate in observed strong TCs. Since the theory without DH predicts a dependence of TC PIR on the square of the MPI, the inclusion of DH results in an even higher PIR for strong TCs. Considering the projected increase in TC MPI under global warming, the theoretical work implies that as the climate continues to warm, TCs may intensify more rapidly. This may not only make the TC intensity forecasting more difficult, but also may increase the threats of TCs to the coastal populations if TCs intensify more rapidly just before they make landfall.

Why Does the Initial Wind Profile Inside the Radius of Maximum Wind Matter to Tropical Cyclone Development?

“…Although limited high‐resolution observations indicate considerable differences in the wind structure inside the RMW during the development of TCs (Reasor et al., 2013), it is still unclear what the initial inner‐core wind structure is and what determines the inner‐core wind structure inside the RMW of TCs in nature, which could be another topic for a future study when more reliable observational data are available. In addition, recent time‐dependent theories of TC intensification do not include the TC structure parameters (e.g., Wang, Li, Xu, 2021; Wang, Li, Xu, Tan & Lin, 2021; Wang et al., 2022; Xu and Wang, 2022). Since the initial wind profile both inside and outside the RMW may affect the TC intensification (Xu and Wang, 2018b), results from this study also strongly suggest that future efforts in further improving the time‐dependent theory of TC intensification should be devoted to include the TC structure parameters.…”

Recent increases in tropical cyclone rapid intensification events in global offshore regions

“…Wang et al 38 developed the concept of potential intensification rate (PIR) and demonstrated that the intensification rate depends on the square of PI and that PIR must be large for RI to occur. Thus, a higher PI in a warming climate favors an increase in both the lifetime maximum intensity (LMI) and global potential TC intensification rate 39 . However, the potential effects of such environmental factors on the variation of RI in offshore regions remain unclear.…”