World Scientific Series on Asia-Pacific Weather and Climate

World Scientific Series on Asia-Pacific Weather and ClimateThe Multiscale Global Monsoon System, pp. 261-272 (2021) No AccessChapter 21: Review: MJO Propagation over the Maritime ContinentDaehyun Kim, Eric D. Maloney, and Chidong ZhangDaehyun KimDepartment of Atmospheric Sciences, University of Washington, Seattle, WA 98195, USA, Eric D. MaloneyDepartment of Atmospheric Science, Colorado State University, Fort Collins, CO 80521, USA, and Chidong ZhangPacific Marine Environmental Laboratory/NOAA, Seattle, WA 98115, USAhttps://doi.org/10.1142/9789811216602_0021Cited by:1 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: This review focuses on the propagation of the Madden–Julian oscillation (MJO) over the Indo- Pacific Maritime Continent (MC). The MJO tends to detour around the MC into the summer hemisphere. Moreover, the MJO's propagation comes to an end most frequently over the MC, which is often referred to as the "MC barrier effect". This peculiar behavior of the MJO in the MC is poorly represented in weather and climate models, partly due to our incomplete understanding of the interaction between the MJO and the MC. The MJO interacts with monsoon circulations, synoptic variability, and the diurnal cycle over the MC. Existing hypotheses for the MJO detour and the MC barrier effect involve the direct disruption of MJO convection by the presence of the MC islands and topography, processes associated with free tropospheric moistening, the diurnal cycle, and the basic state. The exact roles of these processes in the propagation of the MJO through the MC region need to be better understood. FiguresReferencesRelatedDetailsCited By 1Active and weakening MJO events in the Maritime ContinentBradford S. Barrett, Casey R. Densmore, Pallav Ray and Elizabeth R. Sanabia5 March 2021 | Climate Dynamics, Vol. 57, No. 1-2 The Multiscale Global Monsoon SystemMetrics History PDF download

The western North Pacific anomalous anticyclone (WNPAC) is an important atmospheric circulation system that conveys El Niño impact on East Asian climate. In this review paper, various theories on the formation and maintenance of the WNPAC, including warm pool atmosphere–ocean interaction, Indian Ocean capacitor, a combination mode that emphasizes nonlinear interaction between ENSO and annual cycle, moist enthalpy advection/Rossby wave modulation, and central Pacific SST forcing, are discussed. It is concluded that local atmosphere–ocean interaction and moist enthalpy advection/Rossby wave modulation mechanisms are essential for the initial development and maintenance of the WNPAC during El Niño mature winter and subsequent spring. The Indian Ocean capacitor mechanism does not contribute to the earlier development but helps maintain the WNPAC in El Niño decaying summer. The cold SST anomaly in the western North Pacific, although damped in the summer, also plays a role. An interbasin atmosphere–ocean interaction across the Indo-Pacific warm pool emerges as a new mechanism in summer. In addition, the central Pacific cold SST anomaly may induce the WNPAC during rapid El Niño decaying/La Niña developing or La Niña persisting summer. The near-annual periods predicted by the combination mode theory are hardly detected from observations and thus do not contribute to the formation of the WNPAC. The tropical Atlantic may have a capacitor effect similar to the tropical Indian Ocean.