Spatial distribution and diurnal characteristics of rainfall in South Sumatra and surrounding areas based on Tropical Rainfall Measuring Mission (TRMM) data

Abstract

This study aims to obtain information about the characteristics of rainfall in South Sumatra and its surroundings (Longitudes 99° – 107° East and Latitudes 1° - 5° South), which includes climatological anomalies and shifts in the time of diurnal rainfall peak events. This research data comes from TRMM PR 3B42 v7 with grid spatial resolution of 0.25 ° x 0.25 ° and temporal resolution of 3 hours, which includes two categories, namely climatology data for ten years (2008 – 2017) and 12 months actual data (October 2018 – September 2019), with main attention in December 2018 to February 2019. Climatologically the pattern of rainfall is similar to “Type A” of the Aldrian’s rainfall pattern. Meanwhile, the calculations of anomalies indicated a significant rainfall deficiency, starting in July to September 2019, which can be understood as the impact of the positive Indian Ocean Dipole. On the other hand it was found that the peak of rainfall on the west coast of Sumatra generally occurred at 16:00 to 19:00 (local time), which then shifted increasingly late towards both East (mainland Sumatra) and West (Indian Ocean) as stated by Vincent and Lane. Finally, about 30% of the study area did not experience a shift in peak rainfall time (RP time shift) and 40% of the other area experienced it of ± 3 hours and the rest experienced it with a longer time.