Modulation of Seasonal Precipitation over the Tropical Western/Central Pacific by Convectively Coupled Mixed Rossby–Gravity Waves

Abstract

Abstract The relationship between the interannual variations of the activity of convectively coupled equatorial waves and seasonal mean precipitation in the tropical western to central Pacific Ocean is investigated. It is found that the convectively coupled mixed Rossby–gravity (MRG) waves are highly and negatively correlated with the seasonal precipitation near the equator in boreal summer. It is suggested that the MRG waves, which have convection centers off the equator, suppress the equatorial precipitation. The relation is insignificant in the other seasons, when the interannual variation of sea surface temperature near the equator is greater than in boreal summer. Also, a similar relation is not found in the eastern Pacific in any season.