CAUSE OF THE RAPID WEAKENING OF TYPHOON BEBINCA(0021)IN THE SOUTH CHINA SEA

The cause of the rapid weakening of Typhoon“Bebinca”was analyzed in this paper,by using the NCEP FNL(Final)Operational Global Analysis data on 1°×1°grids and the Tropical Cyclone(TC)Annual Report.The result shows that during the middle to late stage of its life cycle,the meteorological environments did not sustain“Bebinca”to maintain its intensity:the water vapor transport at low level decreased significantly;cold air intruded from north at low to middle level;both the divergence at high level and the convergence at low level reduced at the same time in the late stage.All these above factors restrained the development of“Bebinca”.In particular,the rapid reduction of sea surface temperature(SST)was the main factor that induced the rapid weakening of the Typhoon,which occurred about 6 hour ahead of its weakening.Compared to the 500-850 hPa vertical wind shear,which shows a relatively high correlation with the weakening,the impact of the 200-850 hPa vertical wind shear on the intensity change was not significant.Therefore,the Typhoons in the South China Sea would possibly weaken and disappear rapidly in fall and winter.So we have to pay more attention to the time effectiveness of the forecasting and correct the results in time.

Super Typhoon Hinnamnor(2022)with a Record-Breaking Lifespan over the Western North Pacific

Super Typhoon Hinnamnor(2022)was a rare and unique western North Pacific typhoon,and throughout its lifespan,it exhibited all of the major features that pose current challenges in typhoon research.Specifically,during different stages of its lifespan,it experienced a sudden change of track,underwent rapid intensification,interacted and merged with another vortex,expanded in size,underwent rapid weakening,produced a strong cold wake,exhibited eyewall replacement,and underwent extratropical transition.Therefore,a timely identification and review of these features of Hinnamnor(2022),as reported in this article,will help update and enrich the case sets for each of these scientific issues and provide a background for more in-depth mechanistic studies of typhoon track,intensity,and structural changes in the future.We also believe that Hinnamnor(2022)can serve as an excellent benchmark to quickly evaluate the overall performance of different numerical models in predicting typhoon’s track,intensity,and structural changes.