Combined effect of the QBO and ENSO on the MJO

作     者：SUN Liying WANG Hui LIU Fei SUN Liying;WANG Hui;LIU Fei

作者机构：Earth System Modeling and Climate Dynamics Research CenterNanjing University of Information Science and TechnologyNanjingChina School of Atmospheric SciencesSun Yat-sen UniversityGuangzhouChina 

出 版 物：《Atmospheric and Oceanic Science Letters》 (大气和海洋科学快报（英文版）)

年 卷 期：2019年第12卷第3期

页      面：170-176页

核心收录：

学科分类：07[理学] 

基　　金：supported by the National Natural Science Foundation of China [grant number 41420104002] the China National 973 Project [grant number 2015CB453200] the Public Science and Technology Research Funds Projects of the Ocean[grant number 201505013] the Natural Science Foundation of Jiangsu Province [grant numbers BK20150907 and 14KJA170002] the National Science Foundation of the US [grant number AGS-1540783] 

主　　题：QBO ENSO MJO Maritime Continent diurnal cycle 

摘      要：This study investigates the combined effect of the El Nino–Southern Oscillation(ENSO) and stratospheric quasi-biennial oscillation(QBO) on the Madden Julian Oscillation(MJO). The results show that the western Pacific MJO originating from the Indian Ocean during La Nina/QBO easterly years is stronger than that during El Nino years. This relation, however, disappears during La Nina/QBO westerly years. The reason is that ENSO and the QBO have different effects on each MJO event. For an El Nino year, there is only about one MJO event, and the QBO effect is small. During a La Nina/QBO easterly year, there are 1.7 MJO events, while during a La Nina/QBO westerly year, there are only 0.6 MJO events. El Nino can reinforce the MJO over the western Pacific because of the positive moisture advection of the El Nino mean state by MJO easterly wind anomalies. The QBO mainly affects the MJO over the Maritime Continent region by changing the high-cloud-controlled diurnal cycle;and the Maritime Continent barrier effect is enhanced during the QBO westerly phase because of the strong diurnal cycle. During El Nino years, even the MJO over the Maritime Continent is suppressed by the QBO westerly phase;the MJO can be reinforced over the western Pacific. During La Nina/QBO westerly years,the MJO over the Maritime Continent is suppressed because of the strong Maritime Continent diurnal cycle, and it is further suppressed over the western Pacific because of the lack of a reinforcement process.