Based on the Joint Typhoon Warning Center(JTWC) best-track dataset between 1965 and 2009 and the characteristic parameters including tropical cyclone(TC) position,intensity,path length and direction,a method for objec...Based on the Joint Typhoon Warning Center(JTWC) best-track dataset between 1965 and 2009 and the characteristic parameters including tropical cyclone(TC) position,intensity,path length and direction,a method for objective classification of the Northwestern Pacific tropical cyclone tracks is established by using k-means Clustering.The TC lifespan,energy,active season and landfall probability of seven clusters of tropical cyclone tracks are comparatively analyzed.The characteristics of these parameters are quite different among different tropical cyclone track clusters.From the trend of the past two decades,the frequency of the western recurving cluster(accounting for 21.3% of the total) increased,and the lifespan elongated slightly,which differs from the other clusters.The annual variation of the Power Dissipation Index(PDI) of most clusters mainly depended on the TC intensity and frequency.However,the annual variation of the PDI in the northwestern moving then recurving cluster and the pelagic west-northwest moving cluster mainly depended on the frequency.展开更多
This paper tests the impacts of cloud-induced mass forcing on the moist potential vorticity （MPV） anomaly associated with torrential rains caused by Typhoon No.9914 （Dan） by using fine model simulation data output...This paper tests the impacts of cloud-induced mass forcing on the moist potential vorticity （MPV） anomaly associated with torrential rains caused by Typhoon No.9914 （Dan） by using fine model simulation data outputted by the Fifth-Generation NCAR / Penn State Mesoscale Model （MMS）. The diagnostic results show that the positive MPV anomaly region, which is obtained by integrating the MPV from 600 hPa to 300 hPa in the vertical, roughly coincides with the precipitation at their synchronous stages either in position or in the distribution pattem, and the maximum positive MPV area of Dan is located mainly between 600 hPa and 300 hPa, which is much higher than torrential rain cases. Further analyses also showed that the value of positive MPV anomaly increased or decreased with the development of Dan, and the positive MPV anomaly may also be served as a tracer to indicate the evolution of tropical cyclone intensity.展开更多
基金National Basic Research Program of China(973 Program)(2015CB453200),2012CB955903)National Natural Science Foundation of China(41575083,41575108)Jiangsu Education Science Foundation(13KJA170002)
文摘Based on the Joint Typhoon Warning Center(JTWC) best-track dataset between 1965 and 2009 and the characteristic parameters including tropical cyclone(TC) position,intensity,path length and direction,a method for objective classification of the Northwestern Pacific tropical cyclone tracks is established by using k-means Clustering.The TC lifespan,energy,active season and landfall probability of seven clusters of tropical cyclone tracks are comparatively analyzed.The characteristics of these parameters are quite different among different tropical cyclone track clusters.From the trend of the past two decades,the frequency of the western recurving cluster(accounting for 21.3% of the total) increased,and the lifespan elongated slightly,which differs from the other clusters.The annual variation of the Power Dissipation Index(PDI) of most clusters mainly depended on the TC intensity and frequency.However,the annual variation of the PDI in the northwestern moving then recurving cluster and the pelagic west-northwest moving cluster mainly depended on the frequency.
基金State Key Development Program for Basic Research of China (2009CB421505)National Natural Science Foundation of China (40505009)+1 种基金NMC-TIGGE Program (GYHY200706001)Project of State Key Laboratory of Severe Weather (2008LASW-A01)
文摘This paper tests the impacts of cloud-induced mass forcing on the moist potential vorticity （MPV） anomaly associated with torrential rains caused by Typhoon No.9914 （Dan） by using fine model simulation data outputted by the Fifth-Generation NCAR / Penn State Mesoscale Model （MMS）. The diagnostic results show that the positive MPV anomaly region, which is obtained by integrating the MPV from 600 hPa to 300 hPa in the vertical, roughly coincides with the precipitation at their synchronous stages either in position or in the distribution pattem, and the maximum positive MPV area of Dan is located mainly between 600 hPa and 300 hPa, which is much higher than torrential rain cases. Further analyses also showed that the value of positive MPV anomaly increased or decreased with the development of Dan, and the positive MPV anomaly may also be served as a tracer to indicate the evolution of tropical cyclone intensity.
