IntisariPrediksi kejadian badai guntur menjadi perhatian masyarakat luas karena biasanya disertai dengan curah hujan yang tinggi, terutama untuk wilayah rawan banjir seperti provinsi DKI Jakarta. Penelitian ini bertujuan untuk analisis potensi hujan disertai badai guntur dengan menggunakan data radiosonde, analisis indeks labilitas berdasarkan parameter yang didapat dari radiometer dan analisis tren indeks labilitas 6 jam sebelum kejadian hujan. Ada beberapa tanggal yang menjadi perhatian yaitu hari dimana kejadian hujan disertai badai guntur tinggi pada tanggal 28 - 31 Januari 2016 serta tanggal 14 Februari 2016 dan kejadian hujan tanpa badai guntur pada tanggal 3 - 4 Februari 2016. Hasil penelitian menunjukan bahwa terdapat perbedaan hasil sounding sebelum hujan dan pada saat hujan. Hasil sounding sebelum kejadian hujan memiliki labilitas moderat dan sounding pada saat kejadian hujan/badai guntur memiliki labilitas kuat. Selain itu, data dari radiometer menunjukan perbedaan signifikan antara perubahan tren indeks labilitas pada 6 jam sebelum kejadian hujan yang disertai badai guntur, dan pada kejadian hujan tanpa badai guntur.   AbstractPredictions of a thunderstorm event become an attention for wide society because it is usually accompanied by heavy rainfall, especially for the flood prone area like the province of Jakarta. The objective of this study is to analyze the potential of rain with thunderstorms using radiosonde data, to analyze the lability indices based on parameters that obtained from Radiometer, and to analyze the trends of instability indices in 6 hours before the storm event. There are a few dates that become attention, the day where rain events with thunderstorms is high which is on January 28th - 31st, 2016 and February 14th, 2016, and the rain event without thunderstorm on February 3rd - 4th, 2016. The results showed that there are different sounding results before rain event and when it rains. The sounding result before rain event has moderate lability and sounding result when rain event has strong lability. In addition,  the data from the radiometer showed a significant difference between the predicted 6 hours prior to the event of rain with a thunderstorm and rain without thunderstorm events.

Intisari  DAS Citarum Hulu merupakan salah satu subdas yang paling berpengaruh di DAS Citarum dengan Waduk Sagulingnya. Besarnya debit yang masuk ke waduk menjadi sangat penting demi keberlangsungan kinerja waduk tersebut, misalnya untuk pembangkit listrik. Penelitian ini bertujuan untuk mengetahui karakteristik kekeringan hidrologi, relasinya dengan curah hujan, dan analisis frekuensi kejadian kekeringan hidrologi di DAS Citarum Hulu. Data dari pos duga air Nanjung digunakan dalam menentukan ambang batas kekeringan hidrologi yang kemudian diperoleh karakteristik kekeringan hidrologi. Hasil menunjukan bahwa rata-rata periode kekeringan di DAS Citarum Hulu terjadi mulai dari bulan Juni hingga Oktober. Terdapat keterlambatan antara waktu curah hujan turun dan waktu ketika debit naik akibat input dari curah hujan. Hasil analisis frekuensi menunjukan bahwa kekeringan maksimum yang terjadi pada tahun 1994 memiliki periode ulang 52 tahun dan kekeringan sering terjadi dengan durasi kurang dari 20 hari.  Abstract  Citarum Hulu is one of the most influential Citarum sub-basin with the Saguling Reservoir. The amount of discharge into the reservoir is very important for the sustainability of the reservoir's performance for power plants in example. This study aims to determine the characteristics of hydrological drought, its relationship with precipitation, and frequency analysis of hydrological drought occurrence in Citarum Hulu. Data from Nanjung post are used in determining the threshold of hydrological drought which then acquired the characteristics of hydrological drought. The results showed that the average period of drought in Citarum Hulu occurred from June to October. There is a lag between the time when rainfall drops and the time when the discharge rise due to the input of rainfall. Frequency analysis results showed that the maximum drought that occurred in 1994 had a 52-year return period and drought often occurs with a duration of less than 20 days.

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Intisari Beberapa penelitian terkait kejadian hujan menggunakan beberapa jenis alat seperti Micro Rain Radar (MRR) dan Disdrometer. Kombinasi kedua instrument tersebut dapat memberikan gambaran yang lebih  komprehensif mengenai kejadian hujan mulai dari lapisan atas atmosfer hingga permukaan. Penelitian ini mengamati beberapa kejadian hujan pada puncak musim hujan tahun 2017 dan pergantian tahun 2019/2020 di Kawasan Puspiptek Serpong, Tangerang Selatan dengan menggunakan instrumen MRR dan Disdrometer untuk mengetahui karakteristik distribusi ukuran butir air hujan. Hasil penelitian ini menunjukkan pola sebaran butir air hujan yang berbeda, antara kejadian hujan dengan intensitas sangat lebat dan sangat ringan hingga lebat, baik pada lapisan atas atmosfer maupun permukaan. Selain itu, hasil penelitian ini menunjukkan bahwa kejadian hujan sangat lebat berasal dari kumpulan awan konvektif dengan durasi hujan selama 15-60 menit. Sedangkan, kejadian hujan ringan hingga sedang pada umumnya berasal dari kumpulan awan nimbostratus di level menengah atmosfer dengan durasi hujan sekitar 2-3 jam. Abstract Several studies used some equipment types to observe rain events, such as the Micro Rain Radar (MRR) and Disdrometer. Combining the two can provide a more comprehensive picture of rain events from the upper atmosphere to the surface. This study observed several rain events at the peak of the rainy season in 2017 and the turn of the year 2019/2020 in the Puspiptek Serpong Area, South Tangerang, using MRR and Disdrometer instruments to determine the characteristics of the droplet size distribution. This study's results indicate a different droplet size distribution pattern, between the incidence of rain with very heavy intensity and very light to dense, both in the upper atmosphere and surface. Besides, this study's results indicate that the very heavy rain events come from convective clouds with a 15-60 minutes rain duration. Meanwhile, light to moderate rain events generally come from a group of nimbostratus clouds in the medium-level atmosphere with a rain duration of roundabout 2-3 hours.

Meteorological hazard has been frequently occurred in Indonesia due to torrential rains. It is important to examine the characteristics of the atmosphere during rainy seasons for hazard mitigation. National Laboratory of Weather Modification Technology has conducted a short Intensive Observation Program (IOP) from January 18th to February 16th, 2016 to collect meteorological data in the vicinity of Jakarta Region. During that period several instruments have been used, such as Radar, Microwave Profiling Radiometer, Automatic Weather Station, and Radiosonde. This paper examines the comparison of atmospheric parameters obtained from Radiosonde and Profiling Radiometer during extreme weather days. The results showed that there were significant differences of instability indices of Radiosonde and Profiling Radiometer data: 15 points for KI, 6 points for TT and 100 points for SWEAT. The atmospheric stability indices of the Profiling Radiometer tended to be lower than Radiosonde. A radar image showing a rainstorm as well as rain rate information validates atmospheric index stability data. Radar and atmospheric instability indices data integration can be used as one of the parameters to forecast extreme weather events and as an early warning system of hazard mitigation., 02006 (2018) MATEC Web of Conferences