热带季节内振荡与影响广西的热带气旋生成发展的联系

Relationship betwween Madden-Julian Osciuaton and the development of tropical cyclone in Guangxi

利用1978-2013年美国NOAA逐候MJO指数和中国气象局上海台风研究所热带气旋资料,研究了MJO与影响广西热带气旋发生发展的联系。结果表明,当MJO处于非洲大陆和西印度洋时,热带气旋生成区域上空为异常东风带;而当MJO处于西太平洋时,热带气旋生成区域北侧为东风异常带、南侧为西风异常带,有利于季风槽或气旋性环流加强,导致影响广西热带气旋频数偏多。当MJO处于东印度洋时,南海上空风场存在明显的向南分量,热带气旋生成数少、位置偏南;而当MJO处于东太平洋时,热带西太平洋对流受到抑制,导致影响广西热带气旋偏少。

Using the NOAA climatic MJO index from 1978 to 2013 and tropical cyclone data from the Shanghai Typhoon Institute of the China Meteorological Administration,the role of MJO in affecting the occurrence and development of tropical cyclones in Guangxi was studied.The results showed that when MJO was located in the African and the western Indian Ocean,over the tropical cyclone generation area was anomalous easterly zone.When MJO was in the Western Pacific Ocean,the east wind anomaly zone was in the north and the west wind anomaly zone was in the south of the tropical cyclone generation area,which was conducive to the enhancement of monsoon trough or cyclonic circulation,resulting in more tropical cyclones affecting Guangxi.When MJO was in the East Indian Ocean,there was an obvious southward component in the wind field over the South China Sea,and the number of tropical cyclones was less and the position was south;while when MJO was in the East Pacific Ocean,the convection in the tropical West Pacific Ocean was restrained,which resulted in less tropical cyclones in Guangxi.