Karakteristik Tren Temporal dan Distribusi Spasial Wet Bulb Globe Temperature (WBGT) sebagai Indeks Heat stress di Pulau Jawa Periode 2000–2024

Abstract

Perubahan iklim berpotensi meningkatkan risiko heat stress di wilayah tropis, termasuk Pulau Jawa yang berpenduduk terbesar di Indonesia. Penelitian ini bertujuan menganalisis karakteristik temporal dan spasial Wet Bulb Globe Temperature (WBGT), tren perubahan, distribusi kategori heat stress, serta keterkaitannya dengan variabilitas iklim ENSO dan IOD di Pulau Jawa selama periode 2000–2024. Penelitian menggunakan data reanalisis ERA5 dan ERA5 HEAT yang diolah menjadi WBGT harian. Analisis meliputi karakterisasi musiman dan spasial, klasifikasi kategori heat stress, uji tren Mann–Kendall dan Sen's Slope, analisis frekuensi kejadian heat stress, identifikasi hotspot, serta korelasi Pearson dengan Oceanic Niño Index (ONI) dan Dipole Mode Index (DMI). Hasil menunjukkan bahwa nilai WBGT tertinggi terjadi pada musim Maret–Mei (MAM), sedangkan terendah pada musim Juni–Agustus (JJA). Secara spasial, wilayah pesisir utara Pulau Jawa, Jakarta, dan sebagian Jawa Timur memiliki tingkat heat stress lebih tinggi dibandingkan wilayah pegunungan. Analisis tren menunjukkan peningkatan WBGT dan frekuensi heat stress, terutama kategori extreme danger (WBGT =30°C), dengan hotspot dominan di Jawa Timur. Kejadian heat stress lebih banyak terjadi pada fase El Niño dibandingkan La Niña, sedangkan fase IOD positif menghasilkan frekuensi lebih tinggi daripada IOD negatif. Meskipun demikian, hubungan ENSO dan IOD terhadap frekuensi heat stress relatif lemah, sehingga peningkatan heat stress di Pulau Jawa lebih dipengaruhi oleh pemanasan jangka panjang dan faktor lingkungan lokal. Kata kunci: ENSO, heat stress, IOD, Pulau Jawa, WBGT

Climate change has increased the risk of heat stress in tropical regions, including Java Island, the most populous island in Indonesia. This study aimed to analyze the temporal and spatial characteristics of Wet Bulb Globe Temperature (WBGT), its trends, the distribution of heat stress categories, and their relationship with El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) during 2000–2024. The study used ERA5 and ERA5-HEAT reanalysis datasets to derive daily WBGT. The analyses included seasonal and spatial characterization, heat stress classification, Mann–Kendall trend analysis, Sen's Slope estimation, heat stress frequency analysis, hotspot identification, and Pearson correlation with the Oceanic Niño Index (ONI) and Dipole Mode Index (DMI). The results showed that the highest WBGT values occurred during March–May (MAM), while the lowest occurred during June–August (JJA). Spatially, the northern coastal region of Java, Jakarta, and parts of East Java experienced higher heat stress than mountainous areas. Trend analysis revealed increasing WBGT and heat stress frequency, particularly for the extreme danger category (WBGT =30°C), with hotspots concentrated in East Java. Heat stress events occurred more frequently during El Niño than La Niña, while positive IOD phases produced higher frequencies than negative IOD phases. Nevertheless, the relationships of ENSO and IOD with heat stress frequency were relatively weak, indicating that increasing heat stress over Java is mainly driven by long-term warming and local environmental factors. Keywords: ENSO, heat stress, IOD, Java Island, WBGT