The impact of intraseasonal oscillations in the tropical atmosphere on the formation of extreme central Vietnam precipitation

Abstract

The present study examined the atmospheric circulations leading to the extraordinary heavy precipitation event that occurred in central Vietnam during 2-5 October 2010. Results from an analysis of data from the Japan Meteorological Agency Climate Data Assimilation System (JCDAS) showed that the combined effects of a westward-propagating synoptic-scale tropical disturbance from the western Pacific and the eastward propagation of a strong active phase of the Madden Julian Oscillation (MJO) from the Indian Ocean were the primary causes. Investigation of MJO activities during the wet season in the region for the 30 years from 1981 to 2010 revealed that the intraseasonal oscillations in the tropical atmosphere are an important factor in the formation of extreme precipitation events in central Vietnam.