Connection of summer rainfall variations in South and East Asia: Role of El Nino-southern oscillation

We have investigated the role of El Nino and the southern oscillation (ENSO) on the connection between summer rainfall variations in South and East Asia on interannual time scales by separating an Indian summer monsoon rainfall index into two parts: one part ENSO related and the other ENSO unrelated. The ENSO-related part is significantly positively (negatively) correlated with the rainfall variations in northern China (southern Japan). The ENSO-unrelated part has significant negative correlations with the rainfall variations in southwestern China. The occurrence of ENSO generally reinforces the connection between the South Asian summer monsoon and East Asian summer rainfall variations. The ENSO-related part affects East Asian summer rainfall variations through two meridional propagation teleconnection patterns: one over the East Asian continent and the other over the western Pacific Ocean. The ENSO-unrelated part connects with East Asian rainfall variations by a zonal propagation pattern over mid-latitudes in the Asian continent. Copyright (C) 2005 Royal Meteorological Society.