Karakteristik dan variabilitas marine heatwave di perairan Indonesia serta keterkaitannya dengan ENSO dan IOD

Abstract

Peningkatan konsentrasi gas rumah kaca menyebabkan ketidakseimbangan energi di bumi yang mendorong peningkatan suhu permukaan laut (Sea Surface Temperature, SST). Letak perairan Indonesia di kawasan Indo-Pacific Warm Pool serta pengaruh variabilitas iklim antartahun, seperti El Niño–Southern Oscillation (ENSO) dan Indian Ocean Dipole (IOD), menjadikan wilayah ini rentan terhadap marine heatwave (MHW). Penelitian ini bertujuan menganalisis karakteristik MHW di perairan Indonesia periode 1986–2024 serta hubungannya dengan variabilitas atmosfer-laut dan variabilitas iklim skala besar dengan menganalisis frekuensi, durasi, dan intensitas MHW di perairan Indonesia. Analisis Empirical Orthogonal Function (EOF) multivariat diterapkan pada frekuensi MHW, SST, kecepatan angin, fluks panas bersih (NHF), dan tekanan permukaan laut (MSLP), sedangkan hubungan keterkaitan dianalisis menggunakan Oceanic Niño Index (ONI) dan Dipole Mode Index (DMI). Hasil menunjukkan frekuensi dan intensitas MHW tertinggi terjadi pada Desember–Februari (DJF), sedangkan total hari terpanjang terjadi pada Juni–Agustus (JJA), dengan dominasi kejadian di wilayah timur Indonesia. Analisis EOF menunjukkan mode pertama tiap musim merepresentasikan mekanisme atmosfer-laut skala besar, sedangkan mode kedua bersifat regional. ENSO menjadi pengontrol utama variabilitas MHW pada musim DJF dan Maret–Mei (MAM), sementara kombinasi El Niño dan IOD positif pada musim JJA dan September–November (SON) memperkuat upwelling sehingga menghambat perkembangan MHW.

The increase of greenhouse gas concentration causes an energy imbalance on Earth and leads to higher sea surface temperature (SST). The location of Indonesian waters in the Indo-Pacific Warm Pool combined with interannual climate variability, such as El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD), which increase their vulnerability to marine heatwave (MHW) events. This study aims to analyze the characteristics of MHWs in Indonesian waters during 1986–2024 and their relationship with atmosphere–ocean variability and large-scale climate variability based on MHW frequency, duration, and intensity. Multivariate Empirical Orthogonal Function (EOF) analysis uses MHW frequency, sea surface temperature (SST), wind speed, net heat flux (NHF), and mean sea level pressure (MSLP), while the relationship with the Oceanic Niño Index (ONI) and Dipole Mode Index (DMI). The results show that the highest MHW frequency and intensity occur during December–February (DJF), while the longest duration occurs during June–August (JJA), with dominant events in eastern Indonesia. EOF analysis shows that the first mode represents large-scale atmosphere-ocean mechanisms, while the second mode has regional characteristics. ENSO becomes the main factor of MHW variability during DJF and March–May (MAM), while the combination of El Niño and positive IOD during JJA and September–November (SON) increases upwelling and inhibits MHW development.