The interannual and interdecadal variability of the Borneo vortex during boreal winter monsoon

Abstract

The boreal winter monsoon over the Malaysian region has long been associated with heavy rainfall activity and flood disaster. One of the main features that characterized this monsoon is the presence of the Borneo vortices. The main purpose of this study is to identify these vortices and determine their long-term climatological behavior over 41 winter monsoon seasons that ran between November and February from 1970 to 2010. Through compositing analysis technique, the results reveal that the Borneo vortices demonstrate strong feedback with regard to different phases of the ENSO, TBO and PDO events, but not the QBO. Furthermore, EN (LN) signal is found to be strong in PDO1 (PDO2) period, while the EN (LN) tends to weaken (enhance) the TBO event. This study also examined two selected events in order to identify the differences between the Borneo vortices of different intensities based on their convective parameters.