EFEK PARAMETERISASI LAPISAN BATAS ATMOSFER TERHADAP PEMBENTUKAN GELOMBANG GRAVITAS DI SUMATERA BARAT [THE EFFECT OF ATMOSPHERIC BOUNDARY LAYER PARAMETERIZATION TO THE GENERATION OF GRAVITY WAVES OVER WEST SUMATERA]

Gelombang gravitas berperan dalam sirkulasi dinamika atmosfer dan mempengaruhi proses-proses di Lapisan Batas Atmosfer (LBA). Gelombang gravitas telah diidentifikasi dengan simulasi temperatur potensial dan kecepatan angin menggunakan model Weather Research and Forecasting–Advance Research WRF (WRF-ARW) dengan kondisi inisial dan kondisi batas model dari data final analyses (FNL) tanggal 16–17 Maret 2008. Simulasi dilakukan dalam tiga domain nested (bersarang) dengan resolusi horizontal paling tinggi sebesar 3 km. Metode simulasi dilakukan dengan membandingkan dua skema parameterisasi LBA yang berbeda yakni Medium Range Forecast (MRF) dan Yonsei University (YSU). Metode analisis menggunakan transformasi Fourier dan wavelet. Dari hasil simulasi, gelombang gravitas berhasil diidentifikasi dengan baik menggunakan skema MRF di atas Sumatera Barat saat aktivitas konveksi sedang terjadi dengan nilai Cloud Water Mixing Ratio (CWMR) sekitar 0,1-2,1 g/kg. Ciri-ciri gelombang gravitas yang terdeteksi merupakan gelombang gravitas berperiode singkat (~2 jam) dengan panjang gelombang horizontalnya 5–50 km. Perbedaan karakter gelombang gravitas yang dihasilkan simulasi, berhubungan dengan sensitivitas skema parameterisasi LBA dan resolusi grid horizontal. Gelombang gravitas dapat disimulasikan oleh skema MRF dengan resolusi horizontal 3 km yang dapat menghasilkan panjang gelombang yang lebih pendek.Kata kunci: Gelombang gravitas, Lapisan Batas Atmosfer, WRF-ARW, Parameterisas

Propagation Characteristics of Madden Julian Oscillation in the Indonesian Maritime Continent: Case Studies for 2020-2022

Madden-Julian Oscillation (MJO) can affect weather and climate variability in the Indonesian Maritime Continent. MJO propagation is not always the same, previous research has classified MJO into 4 categories: slow, fast, stand, and jump. The objective of this study is to investigate the differences in MJO propagation and the factors that impact it. Daily data for variables such as Outgoing Longwave Radiation (OLR), zonal wind, and sea surface temperature are utilized in this research. The collected data is processed using composite methods based on the 8 MJO phases, with a specific focus on the years 2020, 2021, and 2022. The research findings suggest that warm sea surface temperatures in the Pacific Ocean and zonal winds dominated by Kelvin waves are favorable for MJO propagation. Conversely, cooling sea surface temperatures in the Pacific Ocean and zonal winds dominated by equatorial Rossby waves can hinder MJO propagation. Future researchers are expected to examine the impact of MJO propagation during extreme rainfall occurrences in several regions of Indonesia, as well as the application of machine learning and deep learning methods to predict MJO propagation in the future

2007年1月-2月のジャワ島西部における豪雨に関する数値的研究

京都大学0048新制・課程博士博士(理学)甲第16637号理博第3749号新制||理||1542(附属図書館)29312京都大学大学院理学研究科地球惑星科学専攻(主査)教授 余田 成男, 教授 町田 忍, 准教授 石岡 圭一学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDA

EFEK PARAMETERISASI LAPISAN BATAS ATMOSFER TERHADAP PEMBENTUKAN GELOMBANG GRAVITAS DI SUMATERA BARAT [THE EFFECT OF ATMOSPHERIC BOUNDARY LAYER PARAMETERIZATION TO THE GENERATION OF GRAVITY WAVES OVER WEST SUMATERA]

hal. 33-4

Characterizing The Diurnal Cycle Of Convective Activity Over The South Of West Java Using Doppler X-Band Radar Observations

Routine observations using radar Transportable has been conducted at Pameungpeuk, West Java, focusing on the convective activity in the southern coastal areas of West Java during the rainy season. Structures of spatial and vertical were analyzed during the observation period of 21 days from 12 February to 4 March 2014. The threshold of 10 dBZ was chosen to classify the type of rain clouds (convective / stratiform). The spatial structure was characterized by calculating the frequency of rain events during the period of observation. Whereas the vertical structure was characterized by calculating the radar echo coverage at each altitude. Results showed that convective cloud growth in all areas of radar coverage reached a maximum at about 18-20 and minimum at 7-11 local time (LT). The composite spatial frequency of precipitation events showed that the frequency over land was greater than over the ocean, both for the type of convective and stratiform rain clouds. By dividing into two region, land and sea areas, it was found that the convective activity over land reached a maximum in the afternoon at 15 LT, while over the sea reached a maximum at 2 LT. Maximum convective rain clouds reached earlier than the time maximum of stratiform rain clouds. Analysis of the vertical structure showed that the variation of radar echo reached a maximum at an altitude of 5 km above mean sea level (AMSL) with radar echo coverage over the land was greater than over the ocean. This study showed that the convection activity over land occurring more intense than at sea during the rainy season.Hal.27-3

Fisika, Kimia, dan Dinamika Atmosfer Di Indonesia

v,119p.; 25 c