The Use of Lightning Data for Convective Rainfall Estimation

The objective of this study is to analyse electrification processes in the convective clouds. The intensity of lightning could characterized by three stages of thunderstorm’s life i.e. cumulus, mature and dissipation. First analysis focused on the relationships between lightning and rainfall. To accomplish this goal, a Storm Tracker Lightning Detector was used in the study area for detecting cloud-to-ground lightning (CG). The lag-time between the peak of CG lightning and the peak of rainfall are also being our focus. The results show that surface rainfall tends to follow the lightning (positive lag-time) ±15 minutes after the peak of CG lightning. The index of lightning (L-Index) created to analyse the possibility of heavy rainfall/extreme (>50 mm/day) in 15 minutes ahead, by considering the rainfall categories and normalization of data (from 0 to 1). L-Index of 0 - 0.5 indicating potentially occurs of slight rainfall to moderate rainfall with the intensity of 5-10 mm/hours; and L-Index >0.5 potentially occurs heavy rainfall to extreme rainfall with the intensity > 10 mm/hours

Analisis Tren Perubahan Intensitas Hujan (Studi Kasus: Jakarta dan Bogor)

Abstrak Penelitian ini mengkaji perbedaan Kurva Intensity-Duration-Frequency (IDF) di wilayah Jakarta dan Bogor yang dihitung berdasarkan data Stasiun Kemayoran dan Citeko, terhadap pendekatan Metode Alternating Block Method (ABM), Modified Mononobe, Standar Nasional Indonesia (SNI) Tata Cara Perhitungan Debit Banjir (SNI 2415-2016), dan SNI Tata Cara Perencanaan Drainase Permukaan Jalan (SNI 03-3424-1994). Hasil analisis menunjukkan bahwa curah hujan di wilayah kajian didominasi oleh kejadian ≤ 4 jam dengan rata-rata persentase volume hujan tertinggi pada dua jam pertama yakni 24,9% di Citeko dan 29,9% di Kemayoran. Rata-rata selisih besaran intensitas hujan berdasarkan data observasi dibandingkan dengan pendekatan Metode ABM serta Modified Mononobe mencapai >14%. Intensitas hujan yang dihitung berdasarkan SNI 03-3424-1994 memberikan hasil rata-rata yang lebih tinggi dibandingkan intensitas hujan observasi. Pada periode ulang 2, 5, dan 10 tahun, rata-rata perbedaan intensitas hujan berturut-turut sebesar 26,8 mm/jam, 17,6 mm/jam, dan 11,6 mm/jam di Citeko, serta 36,3 mm/jam, 24,7 mm/jam, dan 17,3 mm/jam di Kemayoran. Perhitungan yang sama menggunakan Modified Mononobe memberikan rata-rata intensitas yang lebih rendah yakni 17 mm/jam, 11,4 mm/jam, dan 8,9 mm/jam di Citeko, namun lebih tinggi sebesar 24,1 mm/jam, 47 mm/jam, dan 49,1 mm/jam di Kemayoran. Kajian ini menggarisbawahi perlunya pengembangan standar desain secara kontinu untuk menghadapi tantangan perubahan iklim. Kata-kata Kunci: Distribusi hujan, intensity-duration-frequency, intensitas hujan, alternating block method, modified mononobe. Abstract This study examines differences between Intensity Duration Curve (IDF) in Jakarta and Bogor Area, represented by Kemayoran and Citeko Rainfall Station, with the Alternating Block Method (ABM), Modified Mononobe, Indonesian National Standard (SNI) for Calculating Flood Discharge, and SNI for Road Surface Drainage Design. The results showed that the rainfall in Jakarta and Bogor mainly was less than 4 hours, with the highest percentage of rainfall volume at the first two hours, about 24.9% at Citeko and 29.9% at Kemayoran. The average bias of rainfall intensity calculated from observation data compared with ABM and Modified Mononobe was >14%. Average rainfall intensity, which was computed using SNI 03-3424-1994 was higher than rainfall intensity calculated from observation data. For the return period of 2, 5, and 10 years, the bias was about 26.8 mm/h, 17.6 mm/h, and 11.6 mm/h, respectively, at Citeko, and 36.3 mm/h, 24.7 mm/h, and 17.3 mm/h, respectively at Kemayoran. Same comparison using Modified Mononobe resulted in lower rainfall intensity about 17 mm/h, 11.4 mm/h, and 8.9 mm/h, respectively at Citeko, and 24.1 mm/h, 47 mm/h, and 49.1 mm/h, respective, at Kemayoran. This study underlined the importance of continuous development of design standards to cope with climate change. Keywords: Intensity-duration-frequency, rainfall distribution, rainfall intensity, alternating block method, modified mononobe.  Rainfall intensity and drainage channel capacity are the main inputs in flood management infrastructure planning. The Intensity-Duration-Frequency (IDF) curve in a region has a different pattern from other regions. This study examines the temporal distribution pattern of rain and the IDF curve with case studies of the Jakarta and Bogor, represented by Kemayoran Rainfall Station and Citeko Rainfall Station, respectively. This study compared data analysis from the above stations with the ABM Method, Modified Mononobe, Indonesian National Standard for Calculating Flood Discharge, and Indonesian National Standard for Road Surface Drainage Design. The analysis results showed that the rainfall event in the Jakarta and Bogor areas was dominated by events of ≤ 4 hours with the highest percentage of rainfall volume at the beginning of the event (at the first two hours of the event). The observed hourly rainfall data has a significant difference pattern with the rainfall distribution calculated using the ABM and Modified Mononobe methods. The IDF curve obtained from the Base Curve on the Indonesian National Standard for Road Surface Drainage Design gives higher results than the IDF curve of the observation data. Meanwhile, the IDF curve calculated using the Mononobe Equation gives lower results than the IDF curve of the observation data. This study shows that standard design of rainfall duration and rainfall intensity for drainage infrastructure planning and flood management need to be continuously developed based on the latest observational data with better temporal and spatial resolution. Continuous effort in improving codes and design standard needs to be conducted to respond to climate change challenges, dynamic regional developments, and the increasing trend of flood events in Indonesia

THE ANALYSIS OF LAPSE RATE PROFILE IN THE SITE CANDIDATE OF NUCLEAR POWER PLANT (NPP) AT GOSONG BEACH, BENGKAYANG REGENCY– WEST KALIMANTAN

The lapse rate profile in the site candidate for the Nuclear Power Plant (NPP) at Gosong Beach Bengkayang, has been investigated to obtain a description of the lability of the atmosphere and upper air as part of a meteorological aspect safety study in the plan to develop a NPP site. The study of the lapse rate was carried out using air data on the reanalysis of the Global Data Assimilation System (GDAS) by extracting air temperature data at each altitude level so as to obtain a lapse rate of up to 25 km. Daily data was processed during 2021 and transformed in the monthly average profile data to describe the lapse rate profile in January – December 2021. Tropopause was identified with average altitude about 16.6 km and stratosphere at 20.5 km with a lapse rate about -0.21 ℃/100 m. The surface layer to 200 m have lapse rate from 0.7 ℃/100 m - 0.9 ℃/100 m at 00.00 Universal Time Coordinated (UTC) and 0.5 ℃/100 m -0.6 ℃/100 m at 12.00 UT

THE ANALYSIS OF LAPSE RATE PROFILE IN THE SITE CANDIDATE OF NUCLEAR POWER PLANT (NPP) AT GOSONG BEACH, BENGKAYANG REGENCY– WEST KALIMANTAN

The lapse rate profile in the site candidate for the Nuclear Power Plant (NPP) at Gosong Beach Bengkayang, has been investigated to obtain a description of the lability of the atmosphere and upper air as part of a meteorological aspect safety study in the plan to develop a NPP site. The study of the lapse rate was carried out using air data on the reanalysis of the Global Data Assimilation System (GDAS) by extracting air temperature data at each altitude level so as to obtain a lapse rate of up to 25 km. Daily data was processed during 2021 and transformed in the monthly average profile data to describe the lapse rate profile in January – December 2021. Tropopause was identified with average altitude about 16.6 km and stratosphere at 20.5 km with a lapse rate about -0.21 ℃/100 m. The surface layer to 200 m have lapse rate from 0.7 ℃/100 m - 0.9 ℃/100 m at 00.00 Universal Time Coordinated (UTC) and 0.5 ℃/100 m -0.6 ℃/100 m at 12.00 UT

A Conceptual Framework for Flood Impact Mitigation Through Transboundary River Management

It is acknowledged that for successful mitigation of flood risk there is a need for an integrated, basin-wide approach. This is particularly important in transboundary river basins that cross administrative borders where the actions of multiple stakeholders must be coordinated from source to mouth. The Ciliwung River, Indonesia, presents an example of a complex urban basin that crosses multiple administrative borders. The increasing frequency and severity of floods in the downstream capital city of Jakarta has highlighted the urgent need for more effective governance arrangements to tackle flooding. However, it is not clear what form these arrangements should take to be effective. In order to understand how transboundary river management arrangements can be improved to mitigate flood hazard impacts, it is first important to identify the nature of the existing management arrangements and how they relate and interact with the flood hazard. To do this, a conceptual framework was developed. The framework firstly outlines the flood hazard itself in terms of drivers and impacts. It then goes on to establish the associated transboundary governance and river management arrangements and seeks to identify any interdependencies. Key concepts were drawn from a review of the literature, conducted using online databases and search engines. The review included published journal and conference papers as well as reports published by organisations which were identified through online searches. The framework highlights multiple interrelated drivers of flood risk, both human and physical. There are also a range of governance issues related to capacities, coordination of institutions and fragmentation of plans and policies identified within the river basin, which need to be overcome. Due to the complexities of flood risk and river management, this conceptual framework provides much needed clarity to facilitate future research on transboundary management in relation to flood risk in urban and peri-urban river basins. It sets a framework for the development of improved transboundary management arrangements in the Ciliwung River Basin

APLIKASI SOFT COMPUTING PADA PREDIKSI CURAH HUJAN DI KALIMANTAN

Analisis clustering curah hujan di Kalimantan menggunakan Jaringan Kompetitif Kohonen menghasilkan 5 kelompok wilayah yang disebut Zona Prediksi. Sementara itu spektrum data memperlihatkan sinyal sunspot hadir dalam deret waktu data curah hujan di semua Zona Prediksi dengan magnitude terbesar pada Zona Prediksi 2 yang mengindikasikan bahwa zona  tersebut memberikan respon langsung pada fenomena sunspot. Peranan aktivitas matahari pada pembentukan awan tinggi dipercayai berkaitan dengan variabilitas fluks sinar kosmik yang bervariasi terhadap lintang. Prediksi curah hujan bulanan dengan Metode ANFIS maupun Jaringan Neural dilakukan dengan menggunakan 1 Prediktor (curah hujan) dan 2 Prediktor (kombinasi antara sinar kosmik dan sunspot) dengan panjang data bervariasi yaitu 45 tahun, 30 tahun, dan 15 tahun  serta panjang data 46 tahun untuk prediksi tahunan (2007–2020). Secara keseluruhan keluaran Metode ANFIS 1 Prediktor menunjukkan nilai rata-rata RMSE (Root Mean Square Error) yang lebih kecil untuk prediksi bulanan. Namun pada prediksi tahunan, Metode ANFIS 2 Prediktor menunjukkan hasil yang lebih baik. Dengan demikian fenomena sunspot dan sinar kosmik sebagai prediktor perlu dipertimbangkan dalam melakukan prediksi jangka panjang karena memberikan akurasi yang lebih baik dibandingkan jika hanya menggunakan curah hujan sebagai prediktor.   Clustering analysis of rainfall using competitive neural Kohonen yields 5 groups area called prediction zone. Meanwhile, data spectrum  shows that sunspot signal exist in time series of rainfall to all of prediction zone with the biggest magnitude at prediction zone 2 and indicates that zone gives direct response to the sunspot phenomena. Role of sunspot activity to the cloud formation believed relationships to the cosmic rays flux that various at latitude. Monthly rainfall prediction with ANFIS Method and Neural Network done with 1 Predictor (rainfall) and 2 Predictors (combine between cosmic rays and sunspot) at various length of data that is 45 years, 30 years, and 15 years and 46 years data length for yearly prediction (2007-2020). Over all, 1 Predictor ANFIS Method shows small average value RMSE (Root Mean Square Error) for monthly prediction. But, for yearly prediction 2 Predictors ANFIS Method shows more accurate. That’s way, sunspot  and cosmic rays phenomena as predictor needs to be considered for long term prediction because gives better accuracy then using rainfall as predictor

KARAKTERISTIK PETIR TERKAIT CURAH HUJAN LEBAT DI WILAYAH BANDUNG, JAWA BARAT

Tulisan ini mencoba untuk menganalisis aktivitas petir menggunakan Lightning Detector sepanjang tahun 2009 dengan radius sekitar 10 km sekitar Bandung. Tujuan analisis adalah untuk identifikasi potensi hubungan antara parameter petir yaitu Cloud-to-Ground (CG) dengan curah hujan lebat di atas 50 mm/hari. Hasil analisis menunjukkan hubungan yang kuat antara CG dan curah hujan lebat serta dominasi CG- (66.1%) sepanjang musim dengan puncak aktivitas pada MAM (43.6%). Pemahaman akan keganjilan aktivitas kilat akan memberikan informasi penting dalam struktur, pertumbuhan awan, labilitas atmosfer ataupun sebagai warning (peringatan) cuaca ekstrim.   The objective of this paper is to analyze the lightning activities using Lightning Detector during the year 2009 with a radius about 10 km around Bandung. The purpose of this analysis is to identify potential relationships between lightning parameters i.e Cloud-to-Ground (CG) with torrential rainfall more than 50 mm/day. The results showed a strong relationships between CG and torrential rainfall and dominance of CG- (66.1%) throughout the season with a  peak at MAM (43.6%). Understanding of the peculiarities of lightning activity will provide important information in the structure, the growth of clouds, atmospheric labilitas or as a warning extreme weather

Komparasi Stasiun Meteorologi Calon Tapak RDNK dengan Kawasan Nuklir Serpong sebagai Upaya Memperkaya Data Pemantauan Cuaca dalam Proses Perizinan

Kajian aspek meteorologi dalam rencana pembangunan Reaktor Daya Non Komersial (RDNK) merupakan salah satu hal penting dalam proses perizinan tapak, tahap konstruksi, komisioning dan operasi. Dalam rangka pemenuhan aspek tersebut, Badan Tenaga Nuklir Nasional (BATAN) membangun stasiun meteorologi di tapak RDNK pada tahun 2018. Hasil evaluasi data cuaca pada stasiun meteorologi RDNK kurang representatif karena pengamatan data dilakukan dalam rentang waktu yang pendek sehingga perlu pengumpulan data cuaca dari stasiun meteorologi lain, yaitu stasiun meteorologi di tapak Kawasan Nuklir Serpong (KNS). Penelitian ini bertujuan membandingkan data cuaca hasil pengukuran dari kedua stasiun meteorologi di tapak KNS dan tapak RDNK sehingga dapat dijadikan justifikasi dalam proses evaluasi tapak RDNK, serta kegiatan evaluasi lanjutan dalam proses perizinan. Parameter cuaca yang diamati dalam penelitian ini meliputi temperatur, tekanan, kelembaban relatif, radiasi matahari dan curah hujan selama satu tahun. Data cuaca yang telah lolos penyaringan dibandingkan pada waktu yang sama. Data tersebut dianalisis menggunakan statistik deskriptif, box-plot, korelasi Pearson, Root Mean Square Error (RMSE), Mean Absolute Error (MAE), analisis regresi linier dan analisis kecenderungan. Hasil kajian menunjukkan adanya korelasi positif yang sangat kuat dan kecenderungan yang sama dari waktu ke waktu antara parameter cuaca di kedua stasiun meteorologi tersebut. Dengan demikian dapat disimpulkan bahwa tapak RDNK memiliki karakteristik meteorologi yang sama dengan tapak KNS

Komparasi Stasiun Meteorologi Calon Tapak RDNK dengan Kawasan Nuklir Serpong sebagai Upaya Memperkaya Data Pemantauan Cuaca dalam Proses Perizinan

Kajian aspek meteorologi dalam rencana pembangunan Reaktor Daya Non Komersial (RDNK) merupakan salah satu hal penting dalam proses perizinan tapak, tahap konstruksi, komisioning dan operasi. Dalam rangka pemenuhan aspek tersebut, Badan Tenaga Nuklir Nasional (BATAN) membangun stasiun meteorologi di tapak RDNK pada tahun 2018. Hasil evaluasi data cuaca pada stasiun meteorologi RDNK kurang representatif karena pengamatan data dilakukan dalam rentang waktu yang pendek sehingga perlu pengumpulan data cuaca dari stasiun meteorologi lain, yaitu stasiun meteorologi di tapak Kawasan Nuklir Serpong (KNS). Penelitian ini bertujuan membandingkan data cuaca hasil pengukuran dari kedua stasiun meteorologi di tapak KNS dan tapak RDNK sehingga dapat dijadikan justifikasi dalam proses evaluasi tapak RDNK, serta kegiatan evaluasi lanjutan dalam proses perizinan. Parameter cuaca yang diamati dalam penelitian ini meliputi temperatur, tekanan, kelembaban relatif, radiasi matahari dan curah hujan selama satu tahun. Data cuaca yang telah lolos penyaringan dibandingkan pada waktu yang sama. Data tersebut dianalisis menggunakan statistik deskriptif, box-plot, korelasi Pearson, Root Mean Square Error (RMSE), Mean Absolute Error (MAE), analisis regresi linier dan analisis kecenderungan. Hasil kajian menunjukkan adanya korelasi positif yang sangat kuat dan kecenderungan yang sama dari waktu ke waktu antara parameter cuaca di kedua stasiun meteorologi tersebut. Dengan demikian dapat disimpulkan bahwa tapak RDNK memiliki karakteristik meteorologi yang sama dengan tapak KNS

ANALISIS DETERMINAN PENDAPATAN PEKERJA PEREMPUAN (RUMAH TANGGA MISKIN) DI KECAMATAN UTAN

This study was conducted on poor household women workers in Utan sub-district. This study aimed to know the effect of work, education level and working hours toward the income of poor female household workers in Utan District, either partially or simultaneously. The type of this study was associative with quantitative data types. The data in this study were primary and secondary. The data collection technique used was interviews. The data analysis techniques used were multiple linear regression, statistical T and F test. The results of the simultaneous test (F-test) showed that work, level of education and working hours together have a significant effect toward the income of poor female household workers in Utan District. Based on the results of the partial test (t-test), the results of this study indicated that the work partially had a positive and significant effect toward the income of poor female household workers, the level of education partially has a negative and significant impact toward the income of poor female household workers, and working hours partially did not affected the income of women workers in poor households