Extreme Drought Characteristics in Java (1960-1965)

Abstract

This study examines the characteristics of the extreme drought experienced in Java between 1960 and 1965, a period marked by consecutive years of dry conditions. The research employs the Standardized Precipitation Index (SPI) to quantify meteorological drought and to assess extreme events as defined by the World Meteorological Organization (WMO), focusing on magnitude, duration, and spatial extent. The analysis identifies extreme drought episodes in 1960 and 1965, with 1964 exhibiting the most extreme magnitude, indicated by SPI-12 values of ≤ -2. These droughts were notably prolonged, with a duration of up to thirty-nine months (from December 1960 to October 1964), and spatial analysis reveals that the southern half of Java was most affected, covering nearly half the region. Further analysis explores the influence of major climate anomalies, including El Niño (Niño 3.4), the Indian Ocean Dipole (IOD), the Pacific Decadal Oscillation (PDO), and other climate indices. Spatial correlation analysis confirms that ENSO and IOD were the dominant drivers, with Niño 3.4 and DMI showing strong negative correlations with SPI-12, particularly across Central and East Java. In contrast, the PDO exhibited a positive correlation with SPI-12, suggesting it may have played a moderating role by enhancing rainfall during its positive phase. The study concludes that drought duration is a critical dimension in defining extreme drought in Java and that accounting for both interannual (ENSO, IOD) and decadal (PDO) variability is essential for improving drought risk forecasting and resilience strategies in vulnerable regions.