Change in rainfall per-decades over Java Island, Indonesia

Abstract

Abstract The frequency of hydro-meteorological disasters (climate and weather-related) in Indonesia has continued to increase in the last ten years. Java Island is the region with the highest disaster occurrence in Indonesia. The CMAP (the CPC Merged Analysis of Precipitation) rainfall data for the long time period 1981-2016 was used in this study. While the in situ data was used for verification of CMAP data. The rainfall is one of the main parameters that affects the climate in Indonesia. A study using this long-term data has been done to investigate the changes of rainfall occurring in Java Island per-decade. The results showed that the annual rainfall pattern appears to be almost the same during the all periods (period I, II, III and IV), but the intensity of the annual rainfall changes significantly. While the real changes are also seen in seasonal rainfall patterns and their intensity on Java Island. These changes indicate that the average rainfall in period IV is higher than period I, II and III. Likewise, the early of the dry/rainy season and the length of the season appear to be shifting in six locations from seven locations of case studies conducted. The CMAP data is quite well as alternative data in climate-related research because it has a good verification of in situ data.