Upper-Ocean Thermal Rejuvenation Within the Typhoon Inactivity Duration Influences Subsequent Typhoon Development

Understanding the upper-ocean thermal response during and between typhoons is critical for accurate prediction of typhoon intensity and for evaluating air–sea interactions. Previous studies have primarily focused on ocean cooling induced by individual typhoons and sea surface temperature (SST) recovery after that, yet oceanic thermal rejuvenation within the typhoon Inactivity Duration and its influence on the subsequent typhoon remains insufficiently explored. Using 42 years of typhoon best-track data, satellite observations and reanalysis data, we provide the first systematic quantification of the physical link between Inactivity Duration and subsequent typhoon intensification. Here we found that the intensity of the subsequent typhoon increased with typhoon Inactivity Duration. The subsequent typhoon is 6.34 kt and 7.69 hPa stronger than the previous typhoon for every 10 days of increase in typhoon Inactivity Duration. Upper-ocean thermal condition rejuvenated with time and contributed to subsequent typhoon development, and both SST and ocean heat content (OHC) exhibited significant phase changes from negative after the preceding typhoon to positive prior to the subsequent one, accompanied by a notable shoaling of the mixed layer depth (MLD) and sustained high levels of atmospheric instability. These coordinated environmental changes provide enhanced energy reserves and more favorable thermodynamic conditions for typhoon development after the inactivity period. These findings highlight the importance of considering ocean thermal rejuvenation in forecasting typhoon intensity and provide a quantitative framework for assessing sequential typhoon interactions with the upper ocean, offering theoretical support for improved intensity forecasting.