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Quick responses in managing peatfire disasters in Indonesia are one key success in mitigating and controlling the risk of peatfire disasters. The aim of this study was to simulate and identify the optimum numbers and locations of fire brigade posts for improving their response times in mitigating peatfire events in Bengkalis Island, Riau, Indonesia. Network analyses were applied in the case of peatfire events on this island. The results of this study may assist local governments and fire brigade teams in developing a strategy to manage peatfires systematically. Hence, the results may contribute to the body of knowledge as a reference in systematically controlling peatfire disasters elsewhere in the world. This study proposed five steps in the identification of appropriate locations of fire brigade posts and performs two main steps to achieve this objective: (i) evaluating existing fire brigade posts’ service coverages; and (ii) developing three scenarios for simulating additions of one, two, and three posts. The results of this study improve fire brigade dispatch time performances as well as expand their service coverage areas from 40.7% to 62.4% within 60 minutes of dispatch time.

This paper presents the application of the weather modification technology (WMT) for mitigation of peatlands fire in Riau Province, Indonesia. The application of WMT has been conducted to reduce the fire disaster risks which were very rare to be implemented in the world. The province of Riau which is about 56% covered with peatlands, is very vulnerable against haze disaster caused by peatlands fires. Peatlands are fragile ecosystems formed over thousands of years by the accumulation of dense wet plant material. When drained or cleared by fire for commercial plantations, such as for palm oil or pulpwood, the carbon is released into the atmosphere. In 2013-2015, Indonesia experienced its most serious fires in some years, worsened by dry weather caused by an El Nino phenomenon, and cloaked large stretches of Southeast Asia in choking smog for mounts. The history proved that the peatlands fires only can be stopped completely by rainfall. On the other hand, the peatland fires usually occur in the dry season that rainfall is very rare. The technology of artificial precipitation has an important role to solve this kind of natural disaster. The aim of this research is to study the impact of the application of the WMT on increasing of precipitation for mitigation of peatlands fire in Riau Province. The analysis was focused on the Kepulauan Meranti and Siak Regency which are very severe peatland fire in 2014, 2015, and 2016. This research found that the application of weather modification technology could increase precipitation occurrence and significantly reduce peatland fire in Riau. The increasing rainfall value (PCH) in Kepulauan Meranti Regency was 1.019, 1.08, 0.68, and 1.649 during the four times WMT application from 2014 to 2016. However, the PCH value in Siak Regency during the four times WMT application in 2014 to 2016 was 1.127, 0.7, 0.66, and 1.88.

In the last 10 years, based on Indonesia’s National Disaster Management Agency (BNPB) data, the number of hydro-meteorological disasters have been increasing. These hydro-meteorological disasters mainly pertain to flood, landslide, wildfire, Small Scale Tornado (SST), among others. High intensity rainfall is an extreme weather condition that is considered as one of the causes of hydrological disasters. Previous researches have mentioned lightning as a good proxy for storm activity. This research aimed to develop an observation and prediction methodology for extreme weather events such as torrential rain based on the combination of continuous lightning measurement and on-demand by surface lightning detection network with remote sensing instrument, a micro-satellite owned by ASEAN countries and Japan. Indonesia already has a network of lightning detection devices that use Very Low Frequencies (VLF) but not too dense. This research will lead to a new methodology in hydro meteorological disaster mitigation, and strengthen and complement already operational extreme weather early warning systems.

Smoke disasters caused by land and forest fires tend to very often occur in peatlands during dry season. Dry season occurs during periods in which rain intensity decreases, causing the land to dry and become prone to burn. Weather modification technology, or WMT, is an alternative solution that can increase rain intensity in a region during dry season by adding NaCl into potential rain clouds. This paper discusses the effectiveness of using WMT during weak El-Nino year in 2014 and strong El-Nino year in 2015 in Ogan Komering Ilir District (Kab. OKI), a region containing numerous peatlands in South Sumatra Province. This study uses track seeding data to determine the location of potential cloud seeding, humidity data to assess the level of atmospheric drought in the region, and rain and hotspot data to analyze the effectiveness of cloud seeding activities in the study period in Kab. OKI. The study results obtained during September–November 2014 and 2015 proved that WMT had been considerably useful, considering that Kab. OKI had relative increase in rainfall intensity and decrease of hotspots during that period. The year 2014 was classified as having weak El-Nino period, in which the rainfall gradient was positive (0.0348) and the gradient hotspot was negative (−0.3846). The same incident occurred in 2015 during a strong El-Nino.

IntisariTelah didesain sebuah usulan pemanfaatan teknologi modifikasi cuaca (TMC) dengan ground-based generator (GBG) untuk menambah debit aliran sungai Mamasa di Sulawesi guna meningkatkan produksi listrik dari Pembangkit Listrik Tenaga Air (PLTA) Bakaru. GBG adalah metode alternatif operasi penyemaian awan dari darat menggunakan menara. Penelitian tentang GBG telah selesai dilakukan di kawasan Puncak Bogor yang merupakan bagian dari sistem orografik Gunung Gede-Pangrango. Daerah Aliran Sungai (DAS) Mamasa memiliki kemiringan lereng antara 25%-40%. Topografi dengan kelerengan curam berada di bagian tengah, sebagian kecil di bagian hulu serta di bagian hilir DAS. Faktor orografi sangat dominan dalam pembentukan awan di DAS Mamasa. Uap air yang masuk ke DAS dipaksa naik oleh pebukitan di batas DAS sehingga terjadi pembentukan awan. Bagian tengah DAS sisi sebelah barat (Sikuku dan Sumarorong) memiliki curah hujan paling banyak sedangkan bagian tengah sisi sebelah timur (Rippung, Tabone, Tatoa dan Salembongan) memiliki curah hujan paling rendah. Hasil kajian topografi merekomendasikan wilayah Sikuku, Makuang dan Sumarorong sebagai lokasi menara GBG. Sementara itu, Polewali direkomendasikan untuk lokasi radar. Karena DAS Mamasa adalah daerah yang rawan longsor maka pembangunan menara GBG disarankan dilakukan pada bulan bulan tidak banyak hujan yaitu pada bulan Juni sampai dengan Agustus.AbstractA proposed use of weather modification technology (TMC) with ground-based generator (GBG) to increase Mamasa river flow in Sulawesi to increase electricity production from Bakaru hydropower was designed. GBG is an alternative method of cloud seeding operations from the ground using towers. Research on GBG has been completed in the area of Puncak, Bogor, which is part of the orographic system Gunung Gede-Pangrango. Mamasa Watershed has a slope of between 25% -40%. Topography with steep slopes are in the middle, a small portion in the upstream and in the downstream of watershed. Orography is very dominant factor in the formation of clouds in the Mamasa watershed. Water vapor that enters the watershed is forced up by the hills in the watershed resulting in the formation of clouds. The middle part of west side (Sikuku and Sumarorong) have the most rainfall, while the central part of the eastern side (Rippung, Tabone, Tatoa and Salembongan) has the lowest rainfall. Results of the assessment of topography recommend the area of Sikuku, Makuang and Sumarorong as GBG tower locations. Meanwhile, Polewali recommended for radar location. Because Mamasa watershed is an area that is prone to landslides, the construction of the GBG tower suggested carried out during June to August.

IntisariTelah dilakukan kajian aplikasi mobile zappeline sebagai media teknologi modifikasi cuaca (tmc) dan media penipisan polutan udara (asap) pada sebuah truk Mitsubishi Colt Diesel berukuran 5,960 x 1,970 meter. Dengan kendaraan tersebut, direkomendasikan dimensi zappeline berbentuk bangun ruang eliptical dengan jari-jari diagonal a dan b masing-masing 3,25 dan 0,65 meter. Selanjutnya, karakteristik aerodinamik dan fisika dihitung dengan memecahkan beberapa persamaan fisika secara numerik pada kondisi atmosfer standart yaitu internasional standart of atmosphere (ISA). Pada kondisi standart ISA, maksimal beban pada ketinggian 1500 meter (5000 feet) sebesar 5,67 kg dan mampu mencapai ketinggian tersebut dalam waktu 1221.93 sekon (+/- 20 menit). Selanjutnya dilakukan perhitungan drag zappeline relatif terhadap udara yang disajikan dalam sebuah grafik yang dapat digunakan bahan pertimbangan dalam desain pendorong zappeline dan perhitungan kekuatan tali. AbstractStudies of mobile zeppeline aplication as a medium of weather modification technology and media thinning air pollutants (smoke) on a Mitsubishi Colt Diesel truck with dimensions of 5,960 x 1,970 meters have been done. With these vehicles, an elliptical zappeline shape geometry are recommended with diagonal radii a and b, 3.25 and 0.65 meters, respectively. Then, the aerodynamics and physics characteristic are calculated by solving some physics equations numerically at standard atmospheric conditions of the international standard atmosphere (ISA). In the ISA standard conditions, the maximum load at 1500 meters altitude (5000 feet) is 5.67 kg and it is capable to reach that altitude in 1221.93 seconds (+/- 20 minutes). Furthermore, calculation of the air drag relative are presented in a graph that can be used in the design considerations of driving force zappeline and calculation of rope tension.

Intisari Telah dilakukan kajian tentang korelasi antara data curah hujan yang terukur di Pos Meteorologi dan data curah hujan yang terukur pada TRMM (Tropical Rainfall Measuring Mission). Data curah hujan merupakan data curah hujan rata – rata harian dibeberapa titik yang ada di Provinsi Riau. Data yang digunakan dalam kajian ini adalah data hujan dari tanggal 16 Maret sampai dengan 28 April 2014. Pengujian korelasi dilakukan dengan menggunakan teknik korelasi Product Moment Pearson dengan asumsi bahwa data terdistribusi normal. Dari hasil perhitungan dengan korelasi Pearson didapatkan nilai korelasi sebesar 0,52. Korelasi yang terhitung sebesar 0,52 masuk kedalam kategori CUKUP. Selain pengujian korelasi, data curah hujan juga dianalisa dengan uji perbandingan streamline yang terbentuk pada diagram kartesius. Tanpa melihat besarnya nilai curah hujan tetapi dengan melihat pola terbentuknya streamline terlihat tanggal 16 Maret sampai dengan tanggal 21 Maret 2014 pola yang terbentuk cenderung berkebalikan dimana ketika data curah hujan pada Posmet turun curah hujan pada TRMM justru malah naik. Sementara mulai tanggal 22 Maret 2014 sampai akhir tanggal 28 April 2014 terlihat tren stream line yang cenderung berpola mirip walaupun ada beberapa titik yang saling berkebalikan sehingga secara umum terlihat polanya mirip.Abstract Studied correlation between data rainfall in Post Meteorological (Posmet) and rainfall data on TRMM (Tropical Rainfall Measuring Mission) have been done. Precipitacion is average rainfall data at the daily average some point in Province of Riau. Data used in this study is data from 16 March to 28 April, 2014. Correlation testing was done by using Pearson Product Moment correlation with assumption that data were normally distributed. From the calculation of Pearson correlation obtained correlation value is 0.52. Correlations were calculated is 0.52, category ENOUGH. In addition to testing the correlation, data rainfall were also analyzed with a streamlined comparison test were formed on Cartesian diagram. Without seeing the value of rainfall but by looking at the pattern formation of streamlined look dated March 16 until March 21, 2014 established pattern which tends to reverse when the rainfall data Posmet down on TRMM rainfall actually even go up. While the start date of March 22, 2014 until the end date of 28 April 2014 visible trends that tend to stream line pattern is similar, although there are a few points of each other so that in general the pattern looks similiar.

IntisariTanaman Kelapa Sawit (Elais sp) adalah sumber utama minyak nabati sesudah kelapa di Indonesia. Tanaman tersebut merupakan komoditi andalan ekonomi Indonesia karena selain merupakan penghasil devisa, kelapa sawit merupakan salah satu alternatif upaya peningkatan kesejahteraan masyarakat melalui pembukaan lapangan pekerjaan dan lapangan usaha. Distribusi tanaman kelapa sawit di Indonesia dapat dijumpai di setiap pulau seperti Sumatera, Kalimantan, Sulawesi dan Jawa. Pada tahun 2013, dari total luas perkebunan kelapa sawit sebesar 9,14 juta hektar, sekitar 65% berada di pulau Sumatera, disusul Kalimantan (31%), Sulawesi (3%), kemudian Jawa dan Papua di bawah satu persen. Tanaman kelapa sawit tergolong ke dalam tanaman xerophyte yang dapat beradaptasi dengan kondisi air yang kurang, walaupun demikian tanaman tetap akan mengalami gejala stres air pada saat musim kemarau yang berkepanjangan. Salah satu upaya untuk mengantisipasi musim kemarau panjang dan kebakaran lahan yaitu dengan melakukan Teknologi Modifikasi Cuaca (TMC). Penerapan TMC di Indonesia sudah dilakukan sejak tahun 1979 dengan berbagai tujuan, yaitu menambah curah hujan untuk mengatasi kekeringan, pengisian air waduk untuk irigasi dan PLTA; mengurangi curah hujan untuk mengatasi banjir; longsor; dan mengurangi kabut asap akibat kebakaran hutan dan lahan. Simulasi proyeksi curah hujan dengan skenario pelaksanaan TMC 120 hari dilakukan di wilayah Riau, Kalimantan Tengah dan Sumatera Utara sebagai daerah dengan luas perkebunan sawit terbesar di Indonesia. Hasil dari simulasi tersebut adalah menghitung besarnya jumlah curah hujan tahunan yang dapat dihasilkan apabila dilakukan TMC 120 hari pada bulan April-Mei 2014 dan Agustus-September 2014 dengan asumsi tingkat pertambahan hujan ketika berada pada periode penyemaian awan sebesar 30%. Berdasarkan hasil simulasi curah hujan dengan skenario pelaksanaan TMC 120 hari, untuk wilayah Riau akan didapatkan penambahan curah hujan sebesar 198 mm/tahun, wilayah Kalimantan Tengah sebesar 254 mm/tahun dan wilayah Sumatera Utara sebesar 233 mm/tahun. Abstract Palm (Elais sp) is the main source of vegetable oil after coco in Indonesia. This plant is mainstay commodity of Indonesia because in addition to foreign exchange earner, palm oil is one alternative efforts to improve the welfare of society through the opening of employment and business field. Distribution of palm oil plantations in Indonesia can be found in every island like Sumatra, Kalimantan, Sulawesi and Java. In 2013, total area of palm oil plantations amounted to 9.14 million hectares, approximately 65% were on the island of Sumatra, Kalimantan followed (31%), Sulawesi (3%), then Java and Papua under one percent. Palm oil plants belonging to the plant xerophyte that can adapt to conditions that are less water, however the plant will continue to experience symptoms of water stress during the long dry season. One effort to anticipate the long dry season and forest fires by performing the Weather Modification Technology. Application of this technology in Indonesia have been carried out since 1979 with a variety of purposes, namely to rain enhancement to overcome drought, filling water reservoirs for irrigation and hydropower; reduce rainfall to overcome floods; landslides; and reduce smog from forest fires and land. Simulation of rainfall projection with applying weather modification technology for 120 days in Riau, Central Kalimantan, and North Sumatra as the area with the largest palm oil plantations in Indonesia. Result of this simulation is to calculate the amount of annual rainfall if weather modification for 120 days applied in April-May 2014 and AugustSeptember 2014, assuming growth rate when cloud seeding period is 30%. Based on this simulation resulted for Riau regoin will get additional rainfall 198 mm/year, Central Kalimantan Region 254 mm/year and North Sumatra Region 233 mm/year

The southern region of Indonesia is one of the places where tropical cyclones grow in the southern hemisphere. During 1983-2017 there were 51 tropical cyclones occurring in the region. This study aims to understand the characteristic of tropical cyclones in southern Indonesia and their variations, both spatially and temporally, and their effect on extreme rain events in Indonesia. Historical data analysis results show that tropical cyclones in southern Indonesia generally occur in November-April with a lifetime of 7-8 days. The result of data analysis shows that the central pressure value of tropical cyclone in latitude 0°-10°S is more than 960 hPa. The value tends to be higher than the central value pressure of tropical cyclone in latitude 10°S-20°S, which has the range of values about 920-960 hPa. This study also explains that there are 9 tropical cyclones in 35 years back that grow or move closer to the Indonesian archipelago in latitude 0°-10°S. The event of tropical cyclone Dahlia at the end of 2017 also affect the enormously increase of rainfall in Gunungkidul, Yogyakarta region with the increase of rain reaches 750% from the historical average.

Flood has always been a problem in Indonesia since the colonization era. First flood occurred on January 10 th, 1932 on Sabang Street. After Indonesian independence in 1945, significant flood events occurred in 1979 and 2007 has caused 4.3 Trillion IDR (T) economic losses and killed 80 persons), 2013 (20 T), 2014 (12 T), and the latest flood event on 9-10 February 2015 had caused a total loss of 10 T IDR (1$=13,000 IDR). The provincial rules in Jakarta Number 20/2013 stated that the 4% of land covered by building must compensate with 4% holes volume on that area. However, the data shown that ±30% of Jakarta's land surface is located under sea level and most building in Jakarta is not follow those rules. Furthermore, the capacity of all drainage in Jakarta has lower capacity than required and only 30% of that drainage working properly. Nowadays, the open green land of Jakarta is only 9.9% with 1.9% change-land use rate per year. Government of Jakarta has policy mentions that every deep-well exploitations must registered with water tax. To anticipate future floods, BPPT has a flood solution concept by combining two activities, for example rain reduction (Weather Modification for Rain Reduction, WM-4-RR; Seto et. al., 2011), and flood reduction with Artificial Recharge Deep Well Injection System (AR-DWIS; Sudinda et.al., 2006-2009), and technology innovation such as WM-RR & AR-DWIS (Goenawan et.al., 2014). The WM-4-RR & AR-DWIS have proven to be able to reduce flood approximately to 33% as stated by Mohajit et.al. (2014). It was assumed that flood peak in Jakarta is equivalent to 800 m 3 /s, therefore Jakarta needs until 2000 AR-DWIS in which each capacity is 400 l/s. While, BPPT and Ristek's building has made experiment & development for AR-DWIS (BR-1) since 2006, the capacity is still 1.43 l/s or 85.71 l/minute or 2.057 m 3 /hour.

Intisari Curah hujan merupakan faktor utama penyebab banjir, tidak terkecuali banjir di wilayah DKI Jakarta. Oleh karena itu, karakteristik curah hujan perlu dipelajari untuk tujuan mitigasi bencana banjir di wilayah Ibukota. Kegiatan riset IOP (Intensive Observation Period) yang telah dilaksanakan oleh BPPT dan BMKG pada tanggal 18 Januari 2016 hingga 16 Februari 2016 bertujuan untuk mengetahui karakteristik atmosfer yang menyebabkan cuaca ekstrim di sekitar wilayah DKI Jakarta. Tulisan ini secara lebih spesifik membahas karakteristik curah hujan dari data satelit TRMM JAXA (Tropical Rainfall Measuring Mission) di Wilayah DKI Jakarta dan sekitarnya, untuk mengetahui bagaimana distribusinya baik secara temporal maupun spasial. Dari hasil pengamatan selama periode kegiatan IOP dapat diketahui bahwa secara temporal distribusi curah hujan yang memiliki intensitas tinggi terjadi pada siang hari (mulai pukul 13.00 WIB) hingga malam hari (pukul 24.00 WIB) dengan intensitas tertinggi terjadi pada rentang waktu antara pukul 13.00 sampai dengan 18.00 WIB. Secara spasial total hujan tertinggi selama periode IOP terpusat di daerah sekitar perbatasan antara Provinsi DKI Jakarta (Jakarta Selatan), Provinsi Jawa Barat (Depok), dan Provinsi Banten (Kota Tangerang Selatan) dengan total curah hujan berkisar antara 600 mm hingga lebih dari 650 mm. Suplai utama curah hujan terbesar adalah hujan-hujan yang terjadi di daerah Selatan hingga bagian tengah Provinsi DKI Jakarta. Abstract Rainfall is a major factor causing flooding, no exception flooding in Jakarta. Therefore, precipitation characteristics need to be studied for the purpose of flood mitigation in the Capital region. Research activities IOP (Intensive Observation Period) have been conducted by BPPT and BMKG on January 18, 2016 until February 16, 2016 aims to determine the characteristics of the atmosphere that causes extreme weather around Jakarta. This paper more specifically discusses the characteristics of rainfall from satellite data TRMM JAXA (Tropical Rainfall Measuring Mission) in the Jakarta area and its surroundings, to know how they were distributed both temporally and spatially. From observations during IOP periods can be seen that the temporal distribution of rainfall high intensity of rain that has occurred during the day (starting at 13.00 pm) until late at night (24.00 pm) with the highest intensity occurred in the period between 13.00 until 18.00. Spatially the highest total of rainfall during the IOP is concentrated in the area around the border between Jakarta (South Jakarta), West Java (Depok), and Banten (South Tangerang City) with total rainfall 600–650 mm. The main supply of the heaviest rainfall was the rain that occurred in the South until the middle part of Jakarta.

This study focuses on features of vertical wind and cloud distributions in Sumatra during the initial phase of a westerly wind burst (WWB) associated with a synoptic-scale super cloud cluster (SCC), by mainly using radar, radiosonde, and lidar data from 5 to 9 May 2004. The convective envelope of the SCC reached Sumatra from the Indian Ocean on 5 May, passing over Sumatra on 7 May. Intensification of the westerly wind occurred over Sumatra below 5.5-6.0 km as the SCC passed over it. On 7 May, the 2.5-4.0 km westerly wind at Kototabang (KT; 0.2°S, 100.32°E, 865 m MSL) was identified as a WWB. Precipitating clouds around KT were suppressed after 7 May, as drier air (lower than 60% relative humidity) was transported from the Indian Ocean over Sumatra at 2.5-6.0 km. Non-precipitation clouds were observed at 5-8 km by the lidar after 7 May.After 7 May, the vertical wind at 2.5-5.5 km showed the oscillatory motion with a timescale of about 12 hours. Similar oscillatory motion was found in the 1.5-2.5 km zonal wind. Contrary to the radiosonde-derived downward wind with a horizontal scale of several hundred km, daily-averaged vertical wind at KT showed upward motion of 0.07-0.08 m s−1 on 7 and 8 May, when westerly winds larger than 10 m s−1 prevailed at 2.5-4.0 km. These facts imply that the topography around KT, which has steep mountains to the west, modulates the behaviors of the vertical wind.The vertical wind oscillation was suppressed above 3.0-5.5 km, where the Richardson number (Ri) was smaller than 0.45 and westerly wind changed to easterly wind. The small Ri was brought about by strong vertical wind shear (larger than 10 m s−1 km−1) and/or weak vertical gradient of potential temperature (smaller than 3 K km−1). Both regions appeared at the upper part of the westerly wind region. This fact implies that shear instability and horizontal wind change inhibit upward propagation of vertical wind oscillations.

Teknologi Modifikasi Cuaca (TMC) telah diaplikasikan untuk mengamankan SEA GAMES 2011 di Palembang, SUmatera Selatan dari ancaman hujan berlebih

Telah dilakukan análisis temporal dan spasial data tekanan udara dan curah hujan menggunakan data hasil pengukuran dengan AWS dan penakar hujan manual di DASLarona, Sulawesi Selatan. Dari hasil analisis temporal nampak bahwa tekanan udarapermukaan cenderung turun saat pertumbuhan awan. Penurunan tekanan menjadi energi yang digunakan untuk menarik massa udara di sekitarnya. Ketika terjadi hujan maka tekanan udara menjadi tinggi akibat adanya pendinginan masa udara. Dari analisisspasial nampak bahwa daerah yang memiliki tekanan lebih rendah cenderung memilikicurah hujan yang lebih tinggi dibandingkan dengan daerah-daerah di sekitarnya. Hasilpenelitian ini bisa dijadikan referensi bahwa ketika terjadi pertumbuhan awan di suatulokasi maka aliran udara akan masuk menuju lokasi pertumbuhan awan. Semakin kuat pertumbuhan awannya maka semakin kuat tarikan massa udara dari sekitarnya. Dalam teknologi modifikasi cuaca, usaha memperkuat pertumbuhan awan mungkin bisa dijadikan salah satu strategi untuk menarik massa udara atau awan-awan yang lebih kecil ke area dengan pertumbuhan awan yang kuat. Namun masih perlu dilakukan penelitian lebih lanjut untuk membuktikan hipotesa ini.Temporal and spatial data analysis of air pressure and rainfall data using AWS andrain gauges in the watershed of Larona, South Sulawesi has been done. From theresults it appears that surface air pressure tends to fall when clouds develop. Pressuredecreasing became energy which is used to draw air mass from the vicinity. When itrains then the air pressure increased due to the cooling of the air. From the spatialanalysis it appears that areas with lower pressure tend to have higher rainfall than thesurrounding areas. The results of this study can be used as a reference that when thereis cloud growth in a location, air flow will go to the location of cloud growth. The stronger cloud’s growth the stronger pull of the surrounding air mass. In weather modification technology, strengthen the growth of cloud technique may be used as one strategy to attract the mass of air or clouds of smaller clouds to the area with strong growth. But it still needs to do further research to prove this hypothesis.

[1] Variations of vertical air velocity (W) in the midlevel shallow-layer clouds are described by a case study observed at West Sumatra, Indonesia (0.2°S, 100.32°E), in the nighttime between 8 and 9 May 2004. By receiving echoes from refractive index irregularities, W and spectral width (σW), used as a proxy of W turbulence, were observed both in clear and cloud regions using frequency power spectrum obtained by a 47-MHz wind profiler with 150-m vertical and 166-s time resolutions. Using altitude profiles of received signal intensity of a 532-nm Mie lidar (Plidar), altitudes with significantly larger Plidar than below (or above) were considered as cloud regions. Most of the shallow-layer clouds were observed between 6.0 and 8.5 km. In the top part of clouds (∼0–500 m below the estimated cloud tops), downward W up to ∼0.2–0.3 m s−1 and σW up to ∼0.5–0.6 m s−1 were observed. In the middle part of clouds (∼500–1000 m below the estimated cloud tops), W showed large variations. Both the standard deviation of W during the observation period and σW were large (∼0.5–0.7 m s−1). These results demonstrate that a combination of VHF wind profiler and lidar is useful to observe wind variations in and around midlevel shallow-layer clouds with high time and vertical resolutions. Altitude profiles of temperature observed by radiosondes showed that the air was absolutely stable near the top part of clouds and conditionally stable below. Possible relationship between W and temperature is discussed.

The influence of intraseasonal variation (ISV) on convective activities over Sumatera (or Sumatra) is studied by using data derived from the Equatorial Atmosphere Radar (EAR), the Boundary Layer Radar (BLR), the surface weather station, the Geostationary Meteorological Satellite (GMS), and NCEP/NCAR reanalysis. In June 2002, convective activities over the Indian Ocean, the maritime continent, and the western Pacific were significantly modulated by the ISV. Blackbody brightness temperature observed by GMS (TBB) showed that two super cloud clusters (SCCs) developed over the Indian Ocean (70-90° E) in the first half of June 2002, and propagated eastward from the Indian Ocean to the western Pacific. Convective activities were enhanced over the western Pacific (130-160° E) in the latter half of June 2002. Convergence at 1000hPa, which prevailed over the Indian Ocean in the first half of June 2002, propagated eastward to the western Pacific in the latter half of June 2002. Zonal wind observed by EAR and surface pressure observed at the observation site suggested the existence of a Kelvin-wave-like structure of ISV. From temporal variations of TBB, zonal wind at 850hPa, and vertical shear of horizontal wind between 700 and 150hPa, we classified the observation periods into the inactive phase (1-9 June), active phase (10-19 June), and postwesterly wind burst phase of ISV (20-26 June). During the inactive phase of ISV, convective activities caused by local circulation were prominent over Sumatera. Results of radar observations indicated the dominance of convective rainfall events over the mountainous area of Sumatera during the inactive phase of ISV. During the active phase of the ISV, cloud clusters (CCs), which developed in the convective envelope of SCC with a period of 1-2 days, mainly induced the formation of convective activities over Sumatera. Results of radar observations indicated that both convective and stratiform rainfall events occurred over the mountainous area of Sumatera during the active phase of ISV. In the postwesterly wind burst phase of ISV, convective activities were suppressed over Sumatera. Features of convective activities found over Sumatera generally agreed well with those found in Tropical Ocean and Global Atmosphere/Coupled Ocean-Atmosphere Response Experiment (TOGA COARE). However, local circulation played an important role in the formation of convective activities over Sumatera in the inactive phase of ISV.

IntisariMasalah pangan bagi suatu negara adalah suatu hal yang sangat krusial mengingat pangan adalah kebutuhan dasar bagi kehidupan manusia. Iklim yang fluktuatif berpengaruh terhadap produksi beras. Saat terjadi anomali iklim di Indonesia yang berakibat pada kekeringan yang berkepanjangan, produksi beras nasional terganggu akibat kurangnya pasokan air irigasi. Teknologi Modifikasi Cuaca (TMC) adalah suatu upaya manusia untuk memodifikasi cuaca dengan tujuan untuk mendapatkan kondisi cuaca seperti yang diinginkan. Penerapan TMC di Indonesia yang sudah dilakukan sejak tahun 1977 memiliki berbagai tujuan, antara lain menambah curah hujan untuk mengatasi kekeringan, serta pengisian air waduk/danau untuk kebutuhan irigasi dan PLTA. TMC pernah diterapkan pada tahun 2007 untuk menambah cadangan air guna meningkatkan produksi beras di Jawa Barat, Jawa Tengah, Jawa Timur, dan Lampung terkait program pemerintah untuk meningkatkan produksi beras nasional sebanyak 2 juta ton. Pada saat itu, TMC berhasil menyumbang peningkatan sebesar 25 %. Berbekal pengalaman tersebut maka TMC diusulkan untuk dilaksanakan di 10 provinsi penghasil beras tertinggi nasional setiap tahun. Penerapan TMC ini diperkirakan dapat meningkatkan produksi beras nasional sehingga tidak diperlukan impor beras bahkan menjadikan Indonesia menjadi surplus beras.AbstractFood problem for a country is a very crucial thing because food is a basic necessity for human life. Climate variability affects rice production. When climate anomalies occurred in Indonesia that resulted in prolonged drought, national rice production disrupted due to the lack of irrigation water supply. Weather Modification Technology (TMC) is a human attempt to modify the weather in order to get the weather conditions as needed. TMC implementation in Indonesia, which has been conducted since 1977 has a variety of purposes, such as rainfall enhancement to overcome the drought, as well as replenishing water reservoirs/lakes for irrigation and hydropower. TMC had applied in 2007 to increase water reserves in order to increase rice production in West Java, Central Java, East Java, and Lampung related government programs to increase national rice production by 2 million tons. At that time, TMC successfully accounted for an increase of 25 %. Based on that experience, TMC is proposed to be implemented in 10 top rice-producing provinces every year. TMC is expected to increase national rice production so as not necessary to import rice even make Indonesia a rice surplus.

IntisariDilatarbelakangi oleh beberapa permasalahan operasional Teknologi Modifikasi Cuaca (TMC) dengan wahana pesawat terbang dan juga permintaan TMC yang semakin meningkat, maka dilakukan pengembangan teknologi Ground-Based Generator berupa desain konseptual Ground-Based Generator (GBG) otomatis dan konsep operasional berbasis wireless sensor network (WSN). Dari kajian teori, teknologi GBG efektif diterapkan dilereng pegunungan, sehingga konsep pengembangan teknologi ini dimaksudkan untuk operasional TMC waduk PLTA di Indonesia yang sebagian besar dikelilingi oleh daerah aliran sungai (DAS) berupa pegunungan. Di dalam tulisan ini dijelaskan 4 topografi waduk PLTA yang telah lama menggunakan jasa TMC yaitu DAS Riamkanan, DAS Larona, DAS Koto Panjang, dan DAS Singkarak. Data topografi yang menunjukkan kelayakan suatu DAS dapat diterapkan GBG diperoleh dari Digital Elevation Model (DEM) dan ditampilkan dengan software Global Maper. Selanjutnya, rancangan GBG otomatis di ilustrasikan dalam sketsa gambar. GBG otomatis memiliki fitur; autoloading flare, rak penyimpanan flare, solar panel, dan dikontrol dengan mikroprosesor. Dengan menerapkan konsep WSN, pengoperasian GBG dapat dilakukan secara terpusat untuk beberapa DAS sekaligus, sehingga kegiatan TMC mejadi lebih efektif dan efisien. AbstractMotivated by some operational problems of Weather Modification Technology (TMC) with airplane medium and also increasing the demand of TMC, then the development of Ground-Based Generator technology in the form of conceptual design of automatic Ground-Based Generator (GBG) and operational concepts based wireless sensor network (WSN) is done. From the study of theory, GBG effectively applied on mountain slope, so the concept of development of this technology is intended for TMC operation in hydroelectric (PLTA) dam in Indonesia that were mostly surrounded by watersheds (DAS) in the form of mountains. This paper describe four hydroelectric dams topography which has long used the TMC service (Riam Kanan DAS, DAS Larona, DAS Koto Panjang, and DAS Singkarak). The topographic data that indicate the feasibility of applied GBG in a watershed is obtained from the Digital Elevation Model (DEM) and displayed with Global Mapper software. Furthermore, the design of automatic GBG is illustrated in sketch drawings. The designed GBG has automatic features; autoloading flares, flare storage racks, solar panels, and controlled by a microprocessor. By applying the concept of WSN, GBG operation can be performed centrally for multiple DAS at once, so that the activities of TMC becoming more effective and efficient.

Paper ini mencoba untuk membuat perhitungan penambahan curah hujan selama periode pelaksanaan kegiatan modifikasi cuaca di DAS Citarum sebagai bentuk lain dari sudut pandang evaluasi hasil kegiatan modifikasi cuaca dengan menggunakan pendekatan statistik. DAS Citarum dipilih sebagai lokasi studi berkaitan dengan jumlah frekuensi kegiatan modifikasi cuaca di daerah tersebut yang relatif banyak dan ketersediaan data historis yang relatif lebih lengkap dibandingkan dengan daerah lain di Indonesia yang juga pernah dilakukan kegiatan modifikasi cuaca

Intisari Pelaksanaan operasi TMC untuk redistribusi curah hujan di Provinsi DKI Jakarta dan sekitarnya dilakukan dengan menggunakan dua metode, yaitu metode mekanisme proses lompatan (jumping process mechanism) dan metode mekanisme persaingan (competition mechanism). Metode mekanisme proses lompatan (jumping process mechanism) dilakukan dengan proses penyemaian awan (cloud seeding) menggunakan bahan semai NaCl yang ditaburkan ke dalam awan menggunakan pesawat terbang. Tujuannya untuk mempercepat proses hujan pada awan-awan Cumulus yang berada di daerah upwind, yang dari radar terpantau bergerak masuk ke arah wilayah Jakarta. Sementara itu, metode mekanisme persaingan (competition mechanism) dilakukan dengan cara membakar bahan semai dalam flare menggunakan wahana penyemaian dari darat (GBG: Ground-Based Generator) yang terpasang di sejumlah lokasi di wilayah Jakarta, mulai dari hulu (daerah Puncak, Bogor) hingga hilir (sekitar Teluk Jakarta). Metode ini bertujuan untuk mengganggu mekanisme fisika awan-awan konvektif yang tumbuh di atas wilayah Jakarta dan berpotensi menjadi hujan. Secara umum, pelaksanaan TMC yang berlangsung selama 33 hari sejak tanggal 26 Januari sampai dengan 27 Februari 2013 berhasil mengurangi intensitas curah hujan dan resiko banjir di wilayah Provinsi DKI Jakarta dan sekitarnya. Selama berlangsungnya pelaksanaan TMC di Provinsi DKI Jakarta, total telah dilakukan 66 sorti penerbangan penyemaian dengan rincian 44 sorti menggunakan pesawat Hercules A-1323 dan 22 sorti menggunakan CASA 212-200 U-616. Total bahan semai NaCl powder yang ditaburkan sebanyak 201,8 ton, sementara dengan GBG telah melakukan pembakaran 486 batang flare di 14 lokasi, dan GBG sistem larutan di 9 lokasi masingmasing selama 158 jam. Berdasarkan data curah hujan historis dari TRMM, curah hujan aktual dari penakar dan TRMM, serta prediksi curah hujan dari GFS diperoleh hasil perhitungan pengurangan curah hujan selama operasional TMC sebesar 20-50%. Abstract Implementation of the TMC operations for the redistribution of rainfall in Jakarta and surrounding areas is done using two methods, namely the jumping process mechanism and the competition mechanism. The jumping process mechanism performed by seeding the clouds using NaCl using aircraft. The goal is to accelerate the process of rain on Cumulus clouds in upwind areas, which is observed (using radar) moving in the direction to Jakarta area. Meanwhile, the competition mechanism is done by burning the material seeding in form of flares using Ground-Based Generator installed in several locations in Jakarta, ranging from upstream (Puncak area, Bogor) to downstream (around the Bay of Jakarta). This method aims to disrupt the cloud physics mechanism for the existence of convective clouds that grow in the area of Jakarta and potential rain.In general, the implementation of the TMC which lasts for 33 days from January 26 until February 27, 2013 managed to reduce the intensity of rainfall and the risk of flooding in areas of Jakarta and its surroundings. During the implementation of the TMC in Jakarta, a total of 66 flight sorties have been carried out with 44 sorties using Hercules aircraft A-1323 and 22 sorties using CASA 212-200 U-616. Total seeding material NaCl powder was 201.8 tons, while the Ground-Base Generators have burned 486 flares in 14 locations, and GBG solution system has operated in 9 locations for 158 hours each. Based on historical rainfall data from TRMM, actual rainfall from raingauge and TRMM, and rainfall predictions obtained by the GFS, rainfall reduction during TMC operation was about 20-50%.