西北太平洋迅速加强热带气旋的高空外流特征分析

CHARACTERISTICS OF THE OUTFLOW LAYER OF TROPICAL CYCLONE RAPID INTENSIFICATION IN THE WESTERN NORTH PACIFIC

选择西北太平洋1979—2012年的259个TC迅速加强(RI)阶段,利用IBTr ACS的TC最佳路径观测资料、高分辨率的卫星观测资料(GOES-10/12 CIMSS、Digital Typhoon),以及高分辨率的大气再分析资料(ERA Interim),针对TC的高空外流通道类型、TC高空外流与周边环境场相互作用的类型进行分类分析。结果表明,迅速加强热带气旋的高空外流特征分为5类:单通道朝向赤道型(S_E)、单通道朝向极地型(S_P)、双通道分别朝向极地与赤道型(D)、无急流通道型(N)、通道转换型(T)。S_E、S_P、D型的RI过程分为8种TC高空外流与周围环境场相互作用的基础类型,南亚高压、南半球的反气旋环流、位于TC东部与西部的中纬度高空槽(或TUTT)是影响TC高空外流的主要天气系统。

Compared to the boundary layer processes, tropical cyclone （TC） outflow layer processes have drawn considerably less attention. It is suggested that tropical cyclone outflow is the link between environmental systems and the inner core. 259 cases of TC rapid intensification （RI） in the Western North Pacific during 1979-2012 were selected. The TC best-track data from the International Best Track Archive for Climate Stewardship （IBTrACS）, high-resolution satellite observation data （GOES-10/12 CIMSS; Digital Typhoon） and high-resolution atmospheric reanalysis data （ERA interim） were used to examine the upper-level outflow channel patterns and outflow interactions associated with TC intensification. There are five outflow patterns associated with the TC RI, which including a single equatorward outflow channel （SE）, a single poleward outflow channel （St）, a double outflow channels （D）, no outflow channel （N）, as well as the transform outflow channels （T）. Eight types of interactions between a TC and its surrounding environment are subdivided from the SE, SP and D outflow patterns. South Asia High, anticyclone of the southern hemisphere and the middle latitude upper-tropospheric trough （or TUTT） are the main systems that enhance the outflow channel.