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Journal : Jurnal Fisika Unand

Pola Sebaran Konvektif Berdasarkan Indeks Konvektif dan Konvergensi Di Sulawesi Selatan Trisnakusumawati, Dofiali Dwi; Sujiono, Eko Hadi; Palloan, Pariabti
Jurnal Fisika Unand Vol 11 No 4 (2022)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.11.4.515-522.2022

Abstract

La Nina merupakan kejadian anomali atmosfer secara global, saat terjadi la nina yang bersamaan dengan musim hujan memberikan dampak signifikan terhadap aktivitas konvektif dan konvergensi. Sulawesi Selatan mempunyai pesisir, dataran tinggi dan terdapat teluk Bone, mempunyai aktivitas konvektif dan konvergensi yang juga berbeda. Penelitian ini bertujuan mengidentifikasi pola aktifitas konvektif berdasarkan indeks konvektif dan nilai konvergensi secara temporal dan spasial pada saat periode La Nina dan normal. Data indeks konvektif dari data satelit dan konvergensi angin permukaan, dilakukan pengolahan berdasarkan musiman DJF, MAM, JJA, dan SON serta harian pagi, siang, malam, dan dini hari. Hasil penelitian menunjukkan nilai konvekstif dan konvergensi saat periode la Nina dan normal musim serta harian mempunyai pola yang sama, yang mebedakan adalah nilai Ic. Aktifitas konvektif kuat terjadi di musim MAM dengan Ic > 30 K, selain itu daratan bagian utara terjadi pola aktivitas konvektif dan konvergensi sepanjang musim, diakibatkan dari topografi pegunungan dan terdapat teluk. Pola sebaran konvektif dan konvergensi di perairan terjadi di pagi dan dini hari (pukul 08.00 dan 02.00 WITA), di darat terjadi di siang hari dan malam hari (pukul 14.00 dan 20.00 WITA), hal ini diakibatkan kuatnya aktifitas angin darat dan angin laut yang menyebabkan perbedaan sebaran konvektif dan konvergensi.
Analysis of Madden-Julian Oscillation (MJO) on extreme rainfall event in the west coastal south Sulawesi for mitigation disaster Matandung, Rekun; Sujiono, Eko Hadi; Subaer, Subaer
Jurnal Fisika Unand Vol 12 No 3 (2023)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.12.3.479-486.2023

Abstract

Madden Julian Oscillation (MJO) is one of the global phenomena that affects weather and climate conditions in Indonesia. MJO increases the rainfall rate and causes a plethora of extreme rainfall occurrences in areas along its trajectory. Those extreme rainfall events could trigger hydrometeorological hazards that endanger the surrounding environment. As the first step to analyse this extreme weather event, this research tries to determine the threshold of the extreme rainfall rate. The method used for determining the threshold is the statistical method 98th percentile. The next step is to identify the frequency trend of the extreme rainfall in the period of 1991 to 2020, by measuring the rainfall rate and comparing it with the normal value. If the rainfall rate is above the normal condition in a certain threshold, then it is considered an extreme rainfall event. After that, these extreme rainfall occurrences are compared to the active MJO phase to find out the influence of MJO to the rainfall in the west coast of South Sulawesi. Then, the dynamical atmospheric conditions are to be analysed during those extreme rainfall events. The result shows that the frequency trend of extreme rainfall events are generally negative in 5 (five) regions, which means an insignificant correlation between MJO and rainfall rate. In contrast, 3 (three) other regions show a positive trend. The influence of an active MJO on the extreme rainfall rate is about 34,1%. Meanwhile, the rest for about 65,9% is influenced by other factors. The use of MJO indices for generating early warning hydrometeorological disasters is by utilising the MJO monitoring data, supported with the analysis of dynamical atmospheric condition in the west coast of South Sulawesi.
Karakteristik Sistem Awan Konvektif Cumulonimbus Berbasis Radar Cuaca C-Band di Sekitar Bandara Internasional Sultan Hasanuddin Makassar Akhirta, Nabilla; Sujiono, Eko Hadi; Palloan, Pariabti
Jurnal Fisika Unand Vol 12 No 4 (2023)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.12.4.568-576.2023

Abstract

Sistem konvektif Cumulonimbus merupakan kumpulan awan yang terdiri dari awan Cumulonimbus dan awan awan lain yang membentuk sebuah sistem, yang dapat menimbulkan cuaca signifikan. Karakteristik fisis dan dinamis Cumulonimbus diperoleh menggunakan radar cuaca C-Band pada musim peralihan dan musim hujan September hingga Februari 2016 – 2022, berpusat pada radius 150 km di sekitar Bandara Internasional Sultan Hasanuddin Makassar. Sembilan tipe morfologi sistem konvektif meso-β ditemukan dengan panjang awan 20-220 km dan panjang rata-rata awan 65 km. Sistem konvektif dominan membentuk sistem linier. Morfologi yang paling banyak terbentuk adalah sistem linier Trailing Stratiform, dan sistem seluler Cluster of Cells. Pada musim peralihan, inisiasi Cumulonimbus dominan di dataran tinggi dan pada musim hujan inisiasi dominan di laut pesisir. Secara umum Cumulonimbus matang di laut pesisir pada siang hari. Cluster of Cells dan Bow Echo adalah sistem yang paling aktif di darat, dengan windshear yang relatif lebih kuat dari semua sistem konvektif. Sistem sebagian besar berpropagasi dengan lambat. Vertical wind shear paling besar terjadi pada lapisan 0,3 – 2 km. Verifikasi dari media massa dan laporan pilot menunjukkan bahwa Cumulonimbus dapat menyebabkan bencana hidrometeorologi dan mengganggu penerbangan.
Analisis Hubungan Ketinggian Planetary Boundary Layer (PBL) dengan Surface Flux di Makassar dan Sekitarnya Lestari, Juliana Tri; Sujiono, Eko Hadi; Arsyad, Muhammad
Jurnal Fisika Unand Vol 13 No 4 (2024)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.13.4.459-468.2024

Abstract

Planetary Boundary Layer (PBL) is influenced by the processes of transfer of momentum, energy, and materials between tPBL and surface layer. Surface fluxes variables consist of Sensible heat flux (SHF) and Latent heat flux (LHF), these variables are also used to measure transport level in this process. Madden Julian Oscillation also contribute in the PBL condition. Therefore, this study was aimed to describe the SHF/LHF and PBL profiles during strong and weak Madden-Julian Oscillation (MJO) periods around Makassar area and its relationship. PBL height was obtained by using the Bulk Richardson Number (Rib) method and bulk aerodynamic for SHF/LHF. Then correlation analysis was done between these two variables. SHF in both strong and weak MJO at 12.00 UTC have greater value than 00.00 UTC, while LHF showed the opposite. PBL height tends to be higher at 00.00 UTC than 12.00 UTC, with the average values were between549,9 to 690,5 m. Annual mean of PBL height ranged between 470 to 1100 m. Maximum average PBL occurred during the transition season I (MAM) at 00.00 UTC, while the minimum happened during transition season 2 (SON) at 12.00 UTC. However, the PBL height profile had shown weak correlation to SHF/LHF value during both MJO strong and weak in Makassar Area.