Relationship between extreme rainfall based on GSMaP data with Madden Julian Oscillation (MJO) in Bangka Island

Abstract

The effect of MJO events on extreme rainfall events on Bangka Island needs to be spatially studied in more detail. The low quality of rain station data encourages the use of alternative data such as Global Satellite Mapping of Precipitation (GSMaP). This study aimed to analyze the influence of active MJO on extreme rainfall events using GSMaP data on Bangka Island. The methods used are extreme threshold of 95th, 98th and 99th percentile, the Spearman Rank correlation between extreme rainfall events and active MJO and its correlation significance test. The results showed that northern coast has the highest range of extreme threshold. The correlation significance test showed GSMaP grids that have a significant correlation with the MJO are in the north of the Island, especially coast area. MJO phases 3 and 5 have an impact on decreasing of extreme rainfall events which are known through the negative correlation values. From all the three extreme thresholds, it was only MJO phase 4 that increasing extreme rainfall events. Active MJO phase 4 causes Bangka Island as a convective area, while MJO phases 3 and 5 affect the formation of suppressed areas on Bangka Island.