The activity of Borneo Vortex as a trigger for extreme rain in West Borneo (case study: 24th – 25th January 2017)

Abstract

On January 24th – 25th, 2017, Borneo Vortex has occurred that started to form at 00.00 UTC and caused the extreme rain in some areas of West Borneo. It recorded 154.1 mm/day of heavy rain in the Ketapang regency, part of West Borneo region that indicated as the effect of Borneo Vortex. The objective of this study was to determine the activity of the Borneo Vortex phenomenon that triggers the extreme rain in some areas of West Borneo. Conducted data for this study obtained from ECMWF reanalysis data for some parameters such as vorticity, divergence, vertical velocity, and humidity transport. Those data used for providing an overview of atmospheric conditions during the Borneo Vortex. Rainfall data from six meteorological stations in West Borneo also used to identify the extreme rain. Regional and local scale analysis conducted to determine changes in atmospheric conditions that occur as triggers of extreme rain in the West Borneo region. The result showed that Borneo Vortex has a significant impact to the changing of atmospheric conditions at the area where close to the forming zone of Borneo Vortex and trigger to increase the convective cloud growing up which affects the increase of rainfall in some areas of West Borneo.