Repositori digital publikasi ilmiah. Memuat artikel , jurnal, dan makalah penelitian terkait meteorologi dan klimatologi.
La Nina is one of the global-scale phenomena that occur in Pacific Ocean. In general, this phenomenon can increase rainfall in Indonesia. La Nina events can last for one year, two years, or even up to three years. When La Nina persists or lasts for three years, it is referred to Triple-Dip La Nina. One such Triple-Dip La Nina occurred during 2020 to 2023. Research on La Nina in Indonesian has been extensive. However, research specifically on Triple-Dip La Nina, particularly during 2020 to 2023, has not been conducted extensively. Therefore, this study aims to analyze Triple-Dip La Nina phenomenon that occurred during 2020 to 2023 and its impact on atmospheric dynamics and rainfall in Indonesia The results showed that the formation of the Triple-Dip La Nina was caused by the intrusion of cold anomalies from the southeastern subtropical region towards the equator of the East Pacific Ocean and the strengthening of the southeast trade wind which was associated with the east trade wind in the equatorial Pacific. Triple-Dip La Nina had varying impacts on atmospheric dynamics and rainfall in Indonesia. During each time period, only the northern and eastern parts of Indonesia, which are closest to the Pacific Ocean, consistently responded positively and were influenced by the Triple-Dip La Nina. In general Triple-Dip La Nina affects almost all regions of Indonesia during JJA (dry season) and SON (transition from dry season to rainy season) periods. During this period there was a strengthening of zonal winds (up to 5 - 7 m/s), an increase relative humidity (up to 6 - 20%) and rainfall (up to 150 mm) in almost all regions of Indonesia.
Hujan lebat merupakan salah satu jenis cuaca ekstrim yang umumnya disebabkan oleh awan Cumulonimbus. Kejadian hujan lebat cukup sering terjadi di wilayah Indonesia, khususnya di wilayah Samarinda selama tahun 2015 – 2022. Penelitian mengenai hujan lebat sudah cukup banyak dilakukan. Pendekatan lain yang dapat digunakan untuk penelitian mengenai hujan lebat adalah dengan menggunakan data pengamatan udara atas. Dari data tersebut dapat diketahui gerak udara dan labilitas atmosfer di suatu wilayah. Salah satu instrumen yang digunakan untuk pengamatan udara atas adalah Pilot Balloon (Pibal). Pemanfaatan data pengamatan Pibal belum cukup banyak dilakukan. Oleh karena itu, dalam penelitian ini akan dilakukan pemanfaatan data pengamatan Pibal untuk analisis kondisi atmosfer sebelum terjadinya hujan lebat di wilayah Samarinda tahun 2015 – 2022. Data pengamatan Pibal diolah menggunakan aplikasi RAOB 5.7, sehingga dapat diketahui gerak udara dan labilitas atmosfer (kecepatan angin 850 mb, Bulk Richardson Number (BRN) Shear, dan Storm Relative Helicity (SRH)). Hasil penelitian ini menunjukkan bahwa sebelum terjadinya hujan lebat gerak udara dari lapisan permukaan hingga ketinggian 3 km umumnya bergerak searah jarum jam (clockwise), yang mengindikasikan adanya aktivitas konvektif yang mendukung pembentukan awan dan terjadinya hujan. Namun, nilai labilitas atmosfer yang teramati sebelumnya terjadinya hujan lebat umumnya relatif rendah. Hanya satu kejadian yaitu pada kejadian – 10 (K10) yang menunjukkan labilitas atmosfer cukup tinggi sehingga dapat meningkatkan aktivitas konvektif dan pembentukan awan Cumulonimbus. Pada K10 teramati adanya peningkatan kecepatan angin lapisan 850 mb yang mencapai 32 knot, serta nilai BRN Shear dan SRH yang cukup tinggi yaitu mencapai 26 m2/ s2 dan 226 m2/ s2.
The development of the Indonesian Capital City (IKN) in Indonesia faces major challenges due to hydrometeorological disasters such as floods and landslides. High rainfall fluctuations, coupled with changes in landuse, have the potential to increase the risk of hydrometeorological disasters. Therefore,acomprehensive mitigation strategy is needed, including adaptation through climate change and weather studies in determining the direction of infrastructure development, to ensure the resilience and safety of the IKN Nusantara area. MJO is one of the factors that can cause high rainfall fluctuations or extreme rain in the Indonesian region. Therefore, this study examines the influence of the MJO phenomenon on rainfall conditions, especially extreme rain events in the IKN area, with a focus only on MJO phases 3, 4, and 5.This study uses rainfall data for 30 years (1991–2020) from meteorological station observation data and the CHIRPS satellite. The results of the study show that MJO significantly affects rainfall conditions, especially extreme rainfall events in the IKN Nusantara region. In addition, this study also succeeded in identifying areas that have significant responses to MJO phases. Generally, the influence of MJO varies by phase and season, both in terms of monthly rainfall accumulation and extreme rainfall events. Some MJO phases increase the average extreme rainfall by up to 20% when the momentum coincides with humid atmospheric conditions that support the formation of convective clouds in the IKN Nusantara region, while other phases can reduce rainfall by up to 5% due to air flow that inhibits the formation of rain clouds incertain areas. This pattern shows a complex interaction between the MJO and local weather variability, which is influenced by seasonal factors and geographical characteristics of the IKN Nusantara region.