Impacts of SST Patterns on Rapid Intensification of Typhoon Megi (2010). Issue 24 (27th December 2017)

• Record Type: Journal Article
• Authors: Kanada, Sachie; Tsujino, Satoki; Aiki, Hidenori; Yoshioka, Mayumi K.; Miyazawa, Yasumasa; Tsuboki, Kazuhisa; Takayabu, Izuru
• Is Part Of: Journal of geophysical research. Volume 122:Issue 24(2017)
• Page Start: 13, 245
• Page End: 13, 262
• Publication Date: 2017-12-27
• Subjects: tropical cyclone -- rapid intensification -- atmosphere‐ocean coupled model; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1002/2017JD027252
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Typhoon Megi (2010), a very intense tropical cyclone with a minimum central pressure of 885 hPa, was characterized by especially rapid intensification. We investigated this intensification process by a simulation experiment using a high‐resolution (0.02° × 0.02°) three‐dimensional atmosphere‐ocean coupled regional model. We also performed a sensitivity experiment with a time‐fixed sea surface temperature (SST). The coupled model successfully simulated the minimum central pressure of Typhoon Megi, whereas the fixed SST experiment simulated an excessively low minimum central pressure of 839 hPa. The simulation results also showed a close relationship between the radial SST profiles and the rapid intensification process. Because the warm sea increased near‐surface water vapor and hence the convective available potential energy, the high SST in the eye region facilitated tall and intense updrafts inside the radius of maximum wind speed and led to the start of rapid intensification. In contrast, high SST outside this radius induced local secondary updrafts that inhibited rapid intensification even if the mean SST in the core region exceeded 29.0°C. These secondary updrafts moved inward and eventually merged with the primary eyewall updrafts. Then the storm intensified rapidly when the high SST appeared in the eye region. Thus, the changes in the local SST pattern around the storm center strongly affected the rapid intensification process by modulating the radial structure of core convection. Our results also show that the use of a high‐resolution three‐dimensional atmosphere‐ocean coupled model offers promise for improving intensity forecasts of tropical cyclones. Key Points: Local SST patterns associated with the storm passage are crucial to simulate accurate intensity of Typhoon Megi Impacts of the SST patterns become obvious when the storm initiates rapid intensification Radial SST profiles have large impacts on structural changes of the storm's inner core prior to rapid intensification