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Megasains
Published by Stasiun Pemantau Atmosfer Global Bukit Kototabang
ISSN : 20865589     EISSN : 27232239     DOI : https://doi.org/10.46824/megasains
Core Subject : Science,
Earth & Planetary Sciences
Buletin MEGASAINS diterbitkan oleh Stasiun Pemantau Atmosfer Global (GAW) Bukit Kototobang sebagai media apresiasi Karya Tulis Ilmiah (KTI) yang bersumber dari kegiatan penelitian berbasis ilmu-ilmu meteorologi, klimatologi, kualitas udara, dan geofisika (MKKuG), serta lingkungan.
Arjuna Subject : Ilmu Bumi dan Planet (semua kategori) - Ilmu Bumi dan Planet (Lain-Lain)
Articles 214 Documents
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Estimasi Debit Aliran Menggunakan Data Radar Cuaca (Studi Kasus : DAS Manna, Bengkulu) HANDOYO, MUHAMMAD FAJAR
Megasains Vol 12 No 2 (2021): Megasains Vol. 12 No. 2 Tahun 2021
Publisher : Stasiun Pemantau Atmosfer Global Bukit Kototabang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46824/megasains.v12i2.64

Abstract

Weather radar has an advantage in estimating rainfall, because it has a high spatial resolution (up to 0.5 km). Weather radar estimate rainfall can be used for various needs, including for hydrological modeling. This study aims to utilize the Bengkulu BMKG weather radar to estimate discharge of the Manna watershed in December 2018. The Z-R equation is determined based on radar reflectivity (Z) and observed rainfall (R) data. Weather radar data processing uses Wradlib software based on the Python programming language. The HEC-GeoHMS and HEC-HMS hydrological models were used to calculate the discharge based on the weather radar rainfall input. The Gridded Soil Conservation Service Curve Number (SCS CN) and ModClark methods are used to determine the method of loss and travel time required for water to the outlet point. Meanwhile, base flow and routing use Recession and Lag methods. As a result, the equation between weather radar reflectivity and observed rainfall is Z=2,65R1,3. The simulation discharge produces an RMSE value of 11.99 m3/second before calibration, and an RMSE of 4.37 m3/second after calibration. In addition, the rainfall forecasted by weather radar has the same pattern as the daily discharge fluctuation of the Manna watershed.
Analisis Karakteristik Fisik dan Meteorologi DAS Bengkulu Faski, Gita Ivana Suci Lestari
Megasains Vol 12 No 2 (2021): Megasains Vol. 12 No. 2 Tahun 2021
Publisher : Stasiun Pemantau Atmosfer Global Bukit Kototabang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46824/megasains.v12i2.69

Abstract

Bengkulu watershed experiences flooding at least two times a year during the rainy season. The flood is one of the hydrometeorological disasters influenced by the physical and meteorological characteristics of the watershed. The characteristics are the basis for planning and management in the watershed. Therefore, this study aims to analyze the physical characteristics and meteorological characteristics of the Bengkulu watershed, as a basis for planning and managing the watershed, to minimize the incidence and impact of hydrometeorological disasters in the watershed. The method used in this research is a quantitative descriptive method of the physical and meteorological characteristics of the Bengkulu watershed. The physical characteristics of the watershed that were analyzed were morphometry, topography, soil type, and land use in the Bengkulu watershed. While the meteorological characteristics analyzed were rainfall and air temperature in the Bengkulu watershed. The results show that the physical characteristics of the Bengkulu watershed have a low capacity to store water, so that the infiltration is small, but the runoff rate is small and the flow type is moderate. However, runoff tends to increase. This is due to decreasing changes in forest land use, supported by increasing rainfall, and small variations in air temperature.
PENGARUH GELOMBANG ULTRA LOW FREQUENCY (ULF) DALAM PERILAKU CACING TANAH DI SOLO DAN KLATEN Pudja, I Putu
Megasains Vol 14 No 2 (2023): Megasains Vol. 14 No. 2 Tahun 2023
Publisher : Stasiun Pemantau Atmosfer Global Bukit Kototabang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46824/megasains.v14i2.71

Abstract

Deformed rocks emit Ultra Low Frequency (ULF) waves and affect the earth's magnetic field. So that ULF gives anomalies to the surroundings. ULF emissions also influence animal behavior. Changes in earthworm behavior in Solo and Klaten on 18 April 2020 coincided with the peak lead time period of deformation calculated by the ULF anomaly on the BMKG magnetograph in Yogyakarta. The location of the discharge area of ​​earthworms is in the deformation coverage area in accordance with the purpose of the interference in the results of the analysis of the magnetograph records. The ULF anomaly in Indonesia is being developed for earthquake prediction, as well as the phenomenon of animal behavior being widely studied for earthquake prediction. Collaboration on animal behavior research, including earthworms and ULF research, provides hope for the development of earthquake predictions in Indonesia.
Pemodelan Perubahan Banjir di Pamenang Barat Menggunakan HECRAS Andarino, Bastian
Megasains Vol 12 No 2 (2021): Megasains Vol. 12 No. 2 Tahun 2021
Publisher : Stasiun Pemantau Atmosfer Global Bukit Kototabang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46824/megasains.v12i2.77

Abstract

Flood is one of the most frequent hydrological disasters in Jambi province. The impact caused by the flood disaster can affect various sectors and cause material losses to fatalities. During the period 2010 to 2019 there have been 149 floods with the area experiencing the most damage, namely the West Pamenang sub-district. West Pamenang District is located in the Batanghari Watershed (DAS) precisely in the Batang Merangin Tembesi sub-watershed. Flood risk analysis can be done by modelling. One application that can be used is HECRAS with debit data input and DEMNAS. One of the outputs of this application is the flood area. The flood area obtained can be used to determine the impact on the physical area of an area, namely by overlaying it with administrative map data. In addition to flood modelling, analysis of daily rainfall trends, monthly rainfall and rainy days is also carried out to determine rainfall changes. The results of the analysis show that there are changes in the trend of daily rainfall, monthly rainfall and rainy days for five rain posts around the West Pamenang sub-district. In addition, daily rainfall is also related to the maximum river discharge. The increase in the maximum river discharge also results in an increase in the flood area which also makes the resulting impact wider.
Pengaruh Seruakan Dingin Asia Terhadap Tinggi Gelombang Maksimum di Selat Karimata dan Laut Jawa Setiawan, Budi
Megasains Vol 12 No 2 (2021): Megasains Vol. 12 No. 2 Tahun 2021
Publisher : Stasiun Pemantau Atmosfer Global Bukit Kototabang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46824/megasains.v12i2.82

Abstract

Indonesia merupakan negara kepulauan di daerah tropis dengan 2 (dua) musim (hujan dan kemarau), yang sebagian besar daerahnya merupakan daerah lautan. Musim di Indonesia sangat dipengaruhi oleh aktivitas monsun dingin Asia Timur yang juga memberikan pengaruh terhadap munculnya aktivitas seruakan dingin Asia yang membawa massa udara dingin dari belahan bumi utara ke belahan bumi selatan melewati daerah kepulauan maritim (cross equatorial flow). Kondisi ini kemudian menyebabkan terbentuknya awan – awan hujan yang merata dengan durasi yang cukup lama di daerah tersebut. Selain berdampak pada meningkatnya intensitas dan durasi hujan, seruakan dingin Asia diduga kuat juga memberikan dampak terhadap peningkatan tinggi gelombang di daerah tersebut. Hal ini dikarenakan pergerakan angin dominan yang bertiup cukup lama sehingga meningkatkan ketinggian gelombang, terutama di Selat Karimata dan Laut Jawa. Dalam penelitian ini dianggap perlu untuk mencari hubungan antara seruakan dingin Asia dengan peningkatan tinggi gelombang, dalam hal ini di Selat Karimata dan Laut Jawa. Pendekatan yang digunakan adalah pendekatan sebab akibat, guna memperoleh gambaran mengenai akibat yang ditimbulkan oleh seruakan dingin terhadap kenaikan tinggi gelombang maksimum. Terdapat jeda waktu antara meningkatnya aktivitas seruakan dingin Asia di Laut Cina Selatan dengan meningkatnya tinggi gelombang di Selat Karimata dan Laut Jawa, sehingga dapat dilakukan antisipasi dini dampak gelombang tinggi yang ditimbulkan. Akhirnya hasil yang diharapkan dalam penelitian ini diharapkan mampu menjadi pengetahuan baru dalam melakukan prediksi tinggi gelombang di Selat Karimata dan Laut Jawa ketika terjadi seruakan dingin Asia.
ANALISIS KUALITAS UDARA PARAMETER PM2.5 DI WILAYAH KOTA SORONG BERBASIS ISPU Syafaati, Ayu Diah
Megasains Vol 14 No 2 (2023): Megasains Vol. 14 No. 2 Tahun 2023
Publisher : Stasiun Pemantau Atmosfer Global Bukit Kototabang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46824/megasains.v14i2.131

Abstract

Sorong City has an area of 1.105 km2 and is the most densely populated area in the Provinces of West Papua and Southwest Papua. As the population in Sorong City increases, human activities also increase which can contribute to increasing PM2,5 particulate concentrations. Sources of particulates in Sorong City came from anthropogenic activities such as city development projects, transportations, biomass burning, and other public activities in the area. PM2,5 that exceeds ambient air quality standards can harm human health. PM2,5 Observations were carried out at Global Atmosphere Watch Sorong Station using BAM Met-One 1020 automatic instrument. BAM-1020 automatically measures and records the level of particle concentrations in the air using Beta Ray Attenuation principle, namely the attenuation of beta particles through the collected solid matter. on fiber filters. PM2,5 solid matter collected in the fiber filter in a volume of ambient air that is drawn by the pump. In general, during September 2021 – June 2023, PM2,5 concentrations tend to increase. The results of the analysis showed that the daily average concentration of PM2,5 measured during September 2021 – June 2023 was in the range 1.21 – 18.71 ug/m3; still below the PM2,5 threshold value of 65 ug/m3 (24 hours). Based on the calculation of the PM2,5 parameter Air Pollutant Standard Index (ISPU), it is known that the ISPU value is in the range 0 – 50. Air quality conditions in Sorong area during this time were in the good category. The influence of meteorological parameters of rainfall and air temperature on PM2,5 concentrations in Sorong City has the most significant and strongest correlation, with a value of r=0.8 (air temperature) and r=-0.7 (rainfall).
Evaluasi Luaran Model S2S (Subseasonal To Seasonal) Ecmwf Dalam Menangkap Variabilitas Hujan Ekstrem Di Sumatera Barat Reyhan, Charisma
Megasains Vol 14 No 2 (2023): Megasains Vol. 14 No. 2 Tahun 2023
Publisher : Stasiun Pemantau Atmosfer Global Bukit Kototabang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46824/megasains.v14i2.137

Abstract

Extreme rain events pose challenges regarding disaster preparedness. Accurate rain prediction is one of the contributions to reducing the impact of extreme events. Predictions on subseasonal to seasonal (S2S) have been developed to fill the gap between short-term weather predictions and long-term seasonal forecasts. This study aims to assess the performance of the S2S model in predicting extreme rainfall events with extreme indices R95p, R99p PRCPTOT, and Rx1day. The data used are the S2S ECMWF data and observational data that were tested at the Stasiun Klimatologi Sumatera Barat and Stasiun Meteorologi Minangkabau during 2017-2022 period. Bias correction of S2S ECMWF data is corrected using the Distribution Mapping method. The results showed that the correlation value at Stasiun Klimatologi Sumatera Barat for daily rainfall ranged from 0.16 to 0.47 and ranged from 0.05 to 0.86 for monthly rainfall. Corrected model data correlation values at the Stasiun Meteorologi Minangkabau ranged from 0.24 to 0.41 for daily rainfall and ranged from 0.27 to 0.62 for monthly rainfall. The RMSE value at the Stasiun Klimatologi Sumatera Barat is smaller than Stasiun Meteorologi Minangkabau. The calculated extreme indices show underestimated values for the R95p, R99p, and overestimated values for the PRCPTOT, and Rx1day.
PENERAPAN IMPUTASI LOCF DAN CROSS MEAN DALAM PENGISIAN DATA KOSONG PADA CURAH HUJAN HARIAN ARG Risnayah, Siti
Megasains Vol 14 No 2 (2023): Megasains Vol. 14 No. 2 Tahun 2023
Publisher : Stasiun Pemantau Atmosfer Global Bukit Kototabang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46824/megasains.v14i2.138

Abstract

The number of installed Automatic Rain Gauges (ARG) today has not been optimally utilized. It is because ARG that works automatically often has missing data due to technical and network problems raising doubts about its accuracy. The data used are ARG rainfall data in 10 minute periods during 2021 and rainfall data from conventional gauge at the same location. The data will be processed until it becomes daily data and will be recovered by missing data entry worked by the Python programming language. Because the ARG data is the longitudinal data type, missing data entry will use LOCF and cross mean imputation. The validity test will compare the recovered ARG data with the conventional gauge data by calculating the MAE, RMSE, and correlation coefficient. The results showed that missing data entry could reduce the percentage of missing from 21.4% to 1.1%. The result of validity tests showed that ARG could produce accurate data determined by a lower error (MAE=0.998mm, RMSE=2.253mm) and a very high correlation (r=0.966). With a higher percentage of data completeness and excellent accuracy, the data usage will become more extensive to provide more benefits, especially for the need of analysis, forecasting, data services, and research.
PREDIKSI KEJADIAN PETIR DENGAN ARTIFICIAL NEURAL NETWORK DI WILAYAH KABUPATEN KEPULAUAN TANIMBAR Prawiro Adiredjo, Indra
Megasains Vol 14 No 2 (2023): Megasains Vol. 14 No. 2 Tahun 2023
Publisher : Stasiun Pemantau Atmosfer Global Bukit Kototabang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46824/megasains.v14i2.140

Abstract

Various research efforts have been made to determine thunderstorm prediction methods, one of which involves using upper air data. However, the use of atmospheric stability threshold values as a reference does not always apply uniformly to all locations due to differences in the characteristics of each region. Therefore, a more objective and precise approach is needed in predicting thunderstorm events, including the application of artificial neural network (ANN) techniques. In this study, the Artificial Neural Network (ANN) method, which is an implementation of artificial intelligence, is used to predict thunderstorm events in the Saumlaki region. The ANN input not only relies on raw data in the form of atmospheric instability index values but also uses feature selection processing to reduce the dimensionality of multivariate input data, minimizing the loss of input data. This process focuses only on essential information and eliminates linear dependencies between features, a technique known as Principal Component Analysis (PCA). The research results indicate that ANN with PCA technique has a higher level of accuracy in predicting thunderstorm events in the Saumlaki region.
IDENTIFIKASI PERUBAHAN CURAH HUJAN DAN SUHU UDARA DI KOTA BENGKULU DAN KABUPATEN KEPAHIANG PROVINSI BENGKULU Muslihah, Dina Whiri; Akmal, Saif
Megasains Vol 15 No 1 (2024): Megasains Vol. 15 No. 1 Tahun 2024
Publisher : Stasiun Pemantau Atmosfer Global Bukit Kototabang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46824/megasains.v15i1.145

Abstract

Climate change has far-reaching impacts in various regions of the world. The chance of extreme climate conditions in the form of high rainfall and drought is increasing as a result of climate change. Indonesia, which is in a tropical region and is a developing country, is vulnerable to being affected by climate change, so it is necessary to analyze climate change in Indonesia. This research analyzes climate change using extreme climate indices produced from the Expert Team for Climate Change Detection and Indices (ETCCDI) study. This index calculates changes in minimum temperature, minimum temperature, and rainfall. Statistical analysis using the Mann-Kendall method was also carried out to see whether or not there were changing trends in climate elements. The data used is data from the Bengkulu Meteorological Station as a representative of the Bengkulu City area which is on the coast and data from the Kepahiang Geophysical Station as a representative of Kepahiang Regency which is in the highland area. The data used is data for the period 1991 – 2020. The results of this research show that there has been a significant change in minimum temperature in both regions.

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