Nur, Muchamad (2025) Karakteristik Hujan Ekstrem Terkait Indian Ocean Dipole (IOD) Dan El Nino Southern Oscillation(ENSO) Di Provinsi Sumatera Utara. Masters thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Curah hujan ekstrem merupakan salah satu dampak signifikan variabilitas iklim di wilayah tropis seperti Sumatera Utara, dan sangat dipengaruhi oleh fenomena Indian Ocean Dipole (IOD) serta El Nino–Southern Oscillation (ENSO). Penelitian ini bertujuan untuk menganalisis karakteristik hujan ekstrem menggunakan indeks ETCCDI, serta mengidentifikasi pengaruh fase ENSO dan IOD terhadap pola ekstrem pada berbagai kondisi topografi. Data yang digunakan meliputi curah hujan observasi BMKG, data satelit CHIRPS resolusi 0.05°, indeks ONI dan DMI selama periode 1994–2023, serta data elevasi DEM SRTM 30 m. Analisis dilakukan dengan perhitungan indeks ekstrem (RX1day, RX5day, R95p, R99p, CDD, CWD), klasifikasi fase ENSO–IOD, serta analisis spasial terkait elevasi. Hasil penelitian menunjukkan bahwa CHIRPS yang telah dikoreksi memiliki akurasi lebih baik dibandingkan data asli sehingga layak digunakan untuk analisis ekstrem spasial. Indeks hujan ekstrem menunjukkan respons yang kuat terhadap variabilitas iklim global. Pada fase El Nino, indeks berbasis intensitas seperti R95p, R99p, RX1day, dan RX5day mengalami penurunan, sementara CDD meningkat, menandakan periode kering yang lebih panjang. Pada fase La Nina, keempat indeks intensitas tersebut meningkat signifikan, disertai penurunan CDD dan peningkatan CWD, yang menunjukkan intensifikasi hujan ekstrem. Fase IOD positif melemahkan kejadian ekstrem, sedangkan IOD negatif memperkuat seluruh indeks hujan ekstrem baik intensitas maupun durasi basah. Secara spasial, respon indeks ekstrem dipengaruhi oleh topografi, di mana wilayah dataran tinggi lebih sensitif terhadap peningkatan ekstrem selama La Nina dan IOD negatif. Penelitian ini menunjukkan bahwa dinamika ENSO dan IOD secara signifikan memengaruhi pola hujan ekstrem di Sumatera Utara, dan integrasi data CHIRPS dengan observasi mampu meningkatkan akurasi karakterisasi ekstrem secara spasial. Temuan ini memberikan dasar ilmiah yang penting bagi pengembangan sistem peringatan dini, perencanaan mitigasi risiko hidrometeorologi, serta adaptasi perubahan iklim di wilayah Sumatera Utara.
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Extreme rainfall is one of the significant impacts of climate variability in tropical regions such as North Sumatra, and is strongly influenced by the Indian Ocean Dipole (IOD) and El Nino-Southern Oscillation (ENSO) phenomena. This study aims to analyze the characteristics of extreme rainfall using the ETCCDI index, and to identify the influence of ENSO and IOD phases on extreme patterns under various topographic conditions. The data used include BMKG rainfall observations, CHIRPS satellite data with a resolution of 0.05°, ONI and DMI indices for the period 1994–2023, and 30 m SRTM DEM elevation data. The analysis was carried out by calculating extreme indices (RX1day, RX5day, R95p, R99p, CDD, CWD), classification of ENSO–IOD phases, and spatial analysis related to elevation. The results show that bias-corrected CHIRPS data exhibit improved accuracy compared to the original dataset, making them suitable for spatial extreme rainfall analysis. Extreme rainfall indices demonstrate a strong response to global climate variability. During El Nino phases, intensity-based indices such as R95p, R99p, RX1day, and RX5day decrease, while CDD increases, indicating longer dry periods. In contrast, La Nina phases significantly enhance all four intensity indices, accompanied by reduced CDD and increased CWD, reflecting intensified extreme rainfall. Positive IOD phases weaken extreme events, whereas negative IOD phases strengthen all extreme rainfall indices, both in intensity and wet-spell duration. Spatially, the response of extreme indices is influenced by topography, with high-elevation areas showing greater sensitivity to extreme increases during La Nina and negative IOD phases. This study demonstrates that ENSO and IOD dynamics significantly affect extreme rainfall patterns in North Sumatra, and that integrating CHIRPS data with observations improves the spatial characterization of rainfall extremes. These findings provide an important scientific basis for developing early warning systems, hydrometeorological risk mitigation strategies, and climate change adaptation efforts in North Sumatra.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | curah hujan ekstrem, Sumatera Utara, Indian Ocean Dipole (IOD), El Nino-Southern Oscillation (ENSO), ETCCDI, CHIRPS Karakteristik. ======================================================================================================================== extreme rainfall, North Sumatra, Indian Ocean Dipole (IOD), El Nino-Southern Oscillation (ENSO), ETCCDI, CHIRPS, characteristics |
| Subjects: | G Geography. Anthropology. Recreation > G Geography (General) > G70.217 Geospatial data G Geography. Anthropology. Recreation > GE Environmental Sciences |
| Divisions: | Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geomatics Engineering > 29101-(S2) Master Thesis |
| Depositing User: | Muchamad Nur |
| Date Deposited: | 29 Jan 2026 04:21 |
| Last Modified: | 29 Jan 2026 04:21 |
| URI: | http://repository.its.ac.id/id/eprint/131007 |
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