Spatiotemporal relation of satellite-based meteorological to agricultural drought in the downstream Citarum watershed, Indonesia

Abstract

Jatiluhur dam, located in West Java province, is one of the most extensive reservoirs in Indonesia and is used to secure the water supply for 240,000 ha of rice fields to prevent agricultural drought in the downstream Citarum watershed. During the last two decades, several areas in the downstream Citarum watershed have been experiencing agricultural drought following meteorological drought events. This study aimed to examine the spatiotemporal patterns of agricultural drought and their correlation with meteorological drought occurrence by utilizing a remote sensing image processing technique. The Normalized Difference Drought Index (NDDI) and Standardized Precipitation Index (SPI) derived from MODIS and CHIRPS data were used to estimate agricultural and meteorological drought events, respectively. The results showed that the magnitude of agricultural drought in the downstream Citarum watershed was varied and related to earlier meteorological drought. The agricultural drought mainly occurred after a meteorological event with the magnitude mostly related to the magnitude of the ONI and DMI. A strong El Nino and positive IOD will cause a higher magnitude of agricultural drought. The time lag between the two drought occurrences was found to be related to the distance of the paddy fields from the main irrigation network and the proximity of the main irrigation network to the Jatiluhur Dam spillway.