Intraseasonal modulation of ENSO teleconnections over East Asia by MJO

The El Nino-Southern Oscillation (ENSO) affects the global and regional climates through the atmospheric teleconnections. During the positive phase of ENSO (El Nino) winters, the surface air temperatures over East Asia (EA) are warmer than normal by El Nino-related anomalous anti-cyclonic flows around Philippine Sea and Kuroshio extension region. However, a weak relationship between El Nino and EA temperature is observed in January due to a retreat of anti-cyclonic circulations. In this study, using the reanalysis data and station observations, we investigate the role of Madden-Julian Oscillation (MJO) on this intraseasonal variations of ENSO teleconnections over EA. During mid-winter, an enhanced MJO activity over Maritime Continent weakens a suppressed convection over the western North Pacific associated with El Nino, possibly breaking the Kuroshio anticyclone. We discuss the possible dynamical mechanism of MJO impacts on ENSO teleconnections.