ANALYSIS OF CHARACTERISTICS EXTREME RAINFALL TRENDS IN WEST JAVA BASED ON IN-SITU DATA

• Main Author: Fujiawati Jaelani, Ghina
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/74789
• Institution: Institut Teknologi Bandung

Extreme rainfall is a condition where rainfall is above or below the normal average which can have significant agricultural, ecological, infrastructural, and social impacts. The magnitude of the frequency, intensity, and duration of extreme rainfall both spatially and temporally is predicted to increase worldwide due to climate change. However, the spatial pattern of extreme rainfall trends is found to be non-uniform in several regions, so that regional scale research in other areas is necessary. For this reason, the characteristics of extreme rainfall trends are analyzed by focusing on the western part of Java. In this study, daily rainfall data from 372 stations were used to determine trends using the four extreme rainfall indices. The RX1d and RI90p indices were chosen as intensity indicators. While CWD and R90p were chosen as frequency indicators. Trends in extreme rainfall are obtained by the Mann-Kendall test and Sen’s slope estimator using a significance level (?) of 0.05. The results showed that most of western Java experienced an increase in extreme rainfall intensity values every year. Meanwhile, the frequency of extreme rainfall has decreased in the north and increased in the highlands and south. Patterns in long-term trends do not represent trend patterns in every decade. In the 1981–2000 period, western Java was dominated by areas with negative trends in both the intensity and frequency of extreme rainfall, while positive trends were seen in the 2001–2020 period. In general, insignificant trends dominate western Java for intensity and frequency indicators. Topography was found to be more significantly associated with the trend of the RX1d index. While the trend of the other three extreme rainfall indices, the topography has a very weak relationship.