Anomalous climatic conditions associated with the El Niño Modoki during boreal winter of 2009

The winter months from December 2009 to February 2010 witnessed extreme conditions affecting lives of millions of people around the globe. During this winter, the El Niño Modoki in the tropical Pacific was a dominant climatic mode. In this study, exclusive impacts of the El Niño Modoki are evaluated with an Atmospheric General Circulation Model. Sensitivity experiments are conducted by selectively specifying anomalies of the observed sea surface temperature in the tropical Pacific. Observed data are also used in the diagnostics to trace the source of forced Rossby waves. Both the observational results and the model simulated results show that the heating associated with the El Niño Modoki in the central tropical Pacific accounted for most of the anomalous conditions observed over southern parts of North America, Europe and over most countries in the Southern Hemisphere viz. Uruguay. Unlike those, the model-simulated results suggest that the anomalously high precipitation observed over Australia and Florida might be associated with the narrow eastern Pacific heating observed during the season.