Incorporating Ocean Waves Improves Forecasts of Strong Tropical Cyclones

Abstract Tropical cyclones (TCs), called typhoons or hurricanes depending on the ocean basin, pose grave threats to lives and property1,2,3. With remote sensing and increasing computing power, more accurate prediction of their stormtracks has been achieved4. However, the destructive power of a TC is related to its intensity. Yet operational forecasts severely underestimate both the rapid intensification (RI) and the peak intensity of strong TCs5,6,7, while overestimate the intensity of weak TCs8,9,10. Here we show that this twin problem can be solved by incorporating the effects of ocean waves at the air-sea interface, which are absent in most forecasting models: Sea sprays generated by wave breaking significantly increase the heat flux to the atmosphere, enhancing both RI and TC peak intensity. For strong winds, reduction of surface drag is observed over foamed ocean surface. These two enhancing effects are balanced for weak TCs by surface-wave mixing, which deepens the ocean mixed layer and decreases sea surface temperature. Post-verification shows that the new model does not suffer the underprediction of RI intensity. The probability of detection increased to 90% when applied for typhoons in the Northwest Pacific. Similar improvements in the quality of prediction can be expected for hurricanes in the Atlantic.