Analisis Mekanisme Pengaruh IOD, ENSO dan Monsun terhadap Suhu Permukaan Laut dan Curah Hujan di Perairan Kepulauan Mentawai, Sumatera Barat

Fenomena El-Niño Southern Oscillation (ENSO) dan Indian Ocean Dipole (IOD) berkaitan erat dengan suhu permukaan laut dan variabilitas curah hujan. Monsun Asia sering menyebabkan hujan lebat termasuk di Sumatera bagian utara sedangkan monsun Australia umumnya menyebabkan kemarau. Perairan Kepulauan Mentawai berada di dekat Samudra Hindia dan dilalui oleh garis khatulistiwa. Hal ini menyebabkan kondisi iklim curah hujan dipengaruhi oleh beberapa faktor seperti suhu muka laut, dipole mode, angin dan Niño 3.4. Data yang digunakan pada penelitian ini adalah data curah hujan (GSMaP), data suhu permukaan laut MUR Level 4 (GHRSST), data angin (ASCAT) yang diolah menggunakan metode komposit serta analisa koefisien korelasi dan koefisien determinasi. Saat fenomena IOD positif, sebesar 60,6% indeks IOD mempengaruhi suhu permukaan laut, sedangkan curah hujan sebesar 21,8%. Saat fenomena ENSO terutama saat La-Niña, indeks ENSO mempengaruhi SPL sebesar 15,8% dan mempengaruhi curah hujan sebesar 6,1%. Monsun asia mempengaruhi SPL sebesar 50,2% sedangkan monsun Australia sebesar 36,7%. Fenomena IOD lebih berpengaruh terhadap SPL dan curah hujan di Perairan Kepulauan Mentawai dibandingkan dengan fenomena ENSO. Saat fenomena El-Niño dan IOD positif suhu permukaan laut menurun diikuti dengan curah hujan rendah. Saat La-Niña dan IOD negatif SPL meningkat diikuti dengan curah hujan yang meningkat. Kecepatan angin yang tinggi menyebabkan SPL merendah.Kata kunci: Curah Hujan, ENSO, IOD, Monsun, SPL Abstract Analysis of Mechanisms of Influence of IOD, ENSO and Monsoon on Sea Surface Temperature and Rainfall in Mentawai Islands Waters, West Sumatra The El-Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) are closely related to sea surface temperature and rainfall variability. The Asian monsoon often causes heavy rains, including in northern Sumatra, while the Australian monsoon generally causes dryness. The sea of the Mentawai Islands are near the Indian Ocean and are traversed by the equator. This causes the climatic conditions of rainfall to be influenced by several factors such as sea surface temperature, dipole mode, wind and Niño 3.4. This research uses rainfall data (GSMaP), sea surface temperature data from MUR Level 4 (GHRSST), wind data (ASCAT) which is processed using the composite method and analysis of correlation coefficients and coefficients of determination. When the IOD is positive, 60.6% of the IOD index affects sea surface temperature, while rainfall is 21.8%. During the ENSO phenomenon, especially during La-Niña, the ENSO index affects SST by 15.8% and affects rainfall by 6.1%. The Asian monsoon affects SST by 50.2% while the Australian monsoon affects 36.7%. The IOD phenomenon has more influence on SST and rainfall in the Mentawai Islands waters compared to the ENSO phenomenon. When the El-Niño and IOD are positive, the sea surface temperature decreases, followed by low rainfall. When La-Niña and IOD are negative the SST increases followed by an increase in rainfall. The high wind speed causes the SST to decrease.Keywords: Rainfall, ENSO, IOD, Monsoon, SS