Analisis spasial kekeringan menggunakan metode standardized precipitation evapotranspiration index di Nusa Tenggara Barat

Abstract

This study investigates the spatial and temporal characteristics of drought in West Nusa Tenggara Province, Indonesia, using the Standardized Precipitation Evapotranspiration Index (SPEI) across multiple time scales (1-, 3-, 6-, 9-, and 12-month). The analysis is based on 29 years of rainfall and climate data (1995–2023) collected from 23 meteorological and climatological stations. Results reveal a distinct seasonal rainfall pattern, with peak precipitation between December and March and severe dry conditions from June to September. Spatial mapping using QGIS and the Inverse Distance Weighting (IDW) interpolation method indicates that eastern Sumbawa, including Bima and Dompu, are highly vulnerable, receiving less than 100 mm of monthly rainfall. Extreme drought events were identified in August 1995, 1998, and 2004, with the lowest SPEI values recorded at Sumi station (-4.07, SPEI-3) and Sepit station (-3.85, SPEI-1). These values reflect significant hydrometeorological stress. Drought classification based on SPEI confirms consistent patterns with historical drought reports. Persistent low SPEI values at longer time scales (SPEI-6 to SPEI-12) highlight the long-term nature of water deficits. The findings underscore the importance of historical drought analysis to support climate-resilient water resource management and proactive mitigation strategies. This research provides valuable input for policymakers in planning adaptive measures in drought-prone regions.