【摘要】 利用1945—2018年美国联合台风警报中心JTWC台风最佳路径资料,定义并系统分析了西北太平洋多台风事件时空分布气候特征和可能形成机制。结果表明:西北太平洋多台风事件(MTYE)主要发生在7—10月,其生成源地关键区位于西北太平洋135°～180°E的12°N附近。相对于单独发生的台风,多台风事件的台风平均强度更强、生命期更长。多台风事件的台风频数占总台风频数的比例以年际变率为主,并有一定的增长趋势。多台风事件强年对应于中东太平洋热带和北半球副热带海温显著增暖,通过Gill型Rossby波响应和Walker环流异常,在西北太平洋产生大气低层相对涡度正异常、中层相对湿度正异常和垂直东风切变异常,为多台风的生成提供了重要的气候背景,季节内多时间尺度瞬变涡旋动能的增强也有重要贡献。更多还原

【Abstract】 The best-track dataset from the Joint Typhoon Warning Center(JTWC) during 1945 to 2018 was used to define and analyze the temporal-spatial distribution characteristics and the possible mechanisms of the western North Pacific Multiple Typhoon Event(MTYE). Results show that MTYE mainly occurs during July to October, and its major genesis location is around 12°N between 135°-180°E over the western North Pacific. Compared to those typhoons occurring individually, the typhoons in MTYE have much larger intensity and longer lifetime. The ratio of typhoon frequency in MTYE to the total mainly shows interannual variability with certain increasing trend. In the MTYE active year, the warming in sea surface temperature is greatly significant in the mid-eastern tropical Pacific and subtropical Pacific in northern hemisphere, which generate Gill-type Rossby wave response and anomalous Walker circulation, and produce low-level positive relative vorticity anomaly, mid-level positive relative humidity anomaly and easterly vertical shear anomaly in turn, providing essential background state for MTYE genesis. Besides, enhancements of eddy kinetic energy at multiple sub-seasonal time scales also have important contributions to the MTYE.更多还原