Differential impacts of conventional El Niño versus El Niño Modoki on Malaysian rainfall anomaly during winter monsoon

This study investigates distinct impacts of conventional El Niño and El Niño Modoki on Malaysian rainfall anomaly during the winter monsoon. Generally, during conventional El Niños, northern Borneo experiences significant rainfall deficit while over Peninsular Malaysia the impact is minimal. In contrast, most El Niño Modoki events favour deficit rainfall over both northern Borneo and Peninsular Malaysia. The level of impacts, particularly over northern Borneo, is higher during El Niño Modoki than conventional El Niño. The different patterns of anomalous rainfall distribution during the two types of El Niño are associated with differences in regional sea surface temperature anomalies, anomalous regional circulation and the different patterns of ascending and descending air associated with the nodes of Walker circulation over this region. However, the most prominent change is the weakening and westward shifting of the anti-cyclonic circulation over the western North Pacific region.