The Quantification of Rainfall Variability Based on the Standardized Precipitation Index

Abstract

The objective of this research is to detect a pattern of rainfall in Gowa Regency using the standardized precipitation index (SPI). The SPI is a tool to investigate wetness and dryness events based on rainfall data in an area. In this study, monthly rainfall data are obtained from 6 rainfall stations. Data are collected from 1988 to 2017. The research result shows that the all stations have the highest frequency of normal condition of rainfall. Meanwhile, the frequency of both extreme wet and extreme dry events is the lowest about 2 percent in most stations. The result also shows that in general, Gowa Regency experiences very wet and very dry events with duration is one month, respectively.