Megasains (Journal)
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RAIN PAUSE (DRY SPELL) AND RAINFALL BASED ON PROBABILITY IN DRY LAND TYPOLOGY IN LOMBOK
No full textJeda hujan (dry spell) dan probabilitas curah hujan sangat esensial bagi pertanian tadah hujan, dan lahan kering. Kedua parameter tersebut sebagai indikator penting status kekeringan dan memiliki relevansi dengan resiko tanaman di daerah tipologi lahan kering. Tujuan penelitian untuk mengetahu durasi jeda hujan (dry spell) dan curah hujan berbasis probabilitas di daerah tipe iklim D dan E Lombok bagian selatan. Penelitan Deskriptif telah dilakukan pada tahun 2014 dengan mengumpulkan data curah hujan harian dari 13 stasiun curah hujan yang ditetapkan secara “‘purposive sampling” mewakili daerah Lombok bagian selatan. Sifat bersyarat atas kejadian hari hujan atau hari tanpa hujan dianalisis menggunakan model rantai Markov level satu, menggunakan data curah hujan harian 16 tahun. Probabilitas curah hujan ditetapkan menggunakan rumus transformasi guna memenuhi sifat distribusi kurva normal. Penilaian tingkat kekeringan musim tanam dilakukan berbasis nilai indeks presipitasi standar (Standarized Precipitation Index, SPI) menggunakan data curah hujan musim tanam rentang 30 tahun. Hasil penelitain menunjukkan, bahwa jeda hujan dan curah hujan berbasis probabiltitas bervariasi secara spasial, dan temporal serta dipengaruhi oleh variasi indek presipitasi standar; jeda hujan semakin ke timur lebih panjang, dan curah hujan berkurang. Jeda hujan bersifat parabolik; selalu lebih panjang pada awal (Nopember) dan akhir musima tanam (April), dan relatif pendek di antaranya. Jeda hujan pada SPI-negatif lebih panjang daripada SPI-positif. Sifat musim tanam mengarah ke sifat kering, dengan harkat agak keringDry spells and the probability of precipitation are very essential for both rainfed and dry land agriculture. The parameters are important indicators of drought status and have relevance to crop risk in dry land areas. The research objective is to determine duration of dry spells and probability-based rainfall in the area of climate types D and E at southern Lombok. Descriptive research was conducted in 2014 by collecting daily rainfall data from 13 rainfall stations. The station are assigned as purposive sampling to represent the southern part of Lombok area. Conditional upon the nature of the incident rainy day or day without rain was analyzed using Markov chain model of level one, using daily rainfall data of 16 years. Probability of precipitation was determined using the formula of transformation in order to meet the normal curve distribution properties. Drought-level assessment carried out based on the value of the standard precipitation index (Standard Precipitation Index, SPI) using growing season rainfall data of span 30 years. The results show, that the dry spells and probability-based rainfall varies spatially and temporally as well as influenced by variations in standard precipitation index; dry sells was longer getting to the east, and rainfall decreased. Dry spell is parabolic; always longer in the early (November) and the end of the growing season (April), and relatively short in between. Dry spell on SPI-negative was longer than the SPI-positive. The nature of the growing season tends to a dry nature, with level of mild drough
EVALUATION OF AUTOMATIC CALIBRATION RESULTS ON CO ANALYZER HORIBA APMA 360 AT SPAG BUKIT KOTOTABANG PERIOD 2012-2015
No full textPenelitian telah dilakukan untuk mengevaluasi hasil automatic calibration pada instrumen CO Analyzer HORIBA APMA 360 di SPAG Bukit Kototabang periode tahun 2012-2015. Automatic Calibration dilakukan dengan cara automatic zero check dan automatic span check. Automatic zero check dilakukan dengan cara memasukkan udara kering bebas karbonmonoksida (CO) ke dalam instrumen. Automatic Span Check dilakukan dengan mencampurkan gas standar karbonmonoksida (CO) konsentrasi 44.86 ± 0.45 ppm dengan udara kering bebas karbonmonoksida (CO) menggunakan dilution unit ke dalam instrumen. Hasil automatic zero check menunjukkan telah terjadi penyimpangan nilai konsentrasi CO sejak 2013 hingga 2015, sedangkan hasil automatic span check menunjukkan bahwa sebagian besar nilai konsentrasi CO berada jauh dibawah nilai teoritis (443 ppb)Research has been conducted to evaluate the results of automatic calibration the instrument CO Analyzer HORIBA APMA 360 at GAW Bukit Kototabang Station in period 2012-2015. Automatic Calibration is done by automatic zero and automatic span check check. Automatic zero check is done by entering the dry air free of carbon monoxide (CO) into the instrument. Automatic Span check is done by mixing the standard gas carbon monoxide (CO) concentrations of 44.86 ± 0:45 ppm with dry air free of carbon monoxide (CO) using a dilution unit into the instrument. Results of automatic zero check indicates there has been a deviation value of the concentration of CO from 2013 to 2015, while the automatic span check results show that most of the CO concentration values are far below the theoretical value (443 ppb
MAPPING THE POTENTIAL THREAT OF LANDSLIDS IN NORTH SUMATRA PROVINCE
No full textInisiasi pemetaan potensi ancaman (hazard) gerakan tanah longsor di Sumatera Utara menjadi prioritas utama dalam mitigasi bencana. Mitigasi bencana gerakan tanah diharapkan mampu mengurangi bahkan menghilangkan dampak dari bencana gerakan tanah longsor. Langkah kongkrit dalam upaya antisipasi penggunaan lahan berwawasan kebencanaan dapat ditempuh melalui pemetaan potensi ancaman (hazard).Bencana dapat timbul sebagai akibat dari aktifitas manusia (antropogenik) dan faktor alam. Pendekatan terhadap faktor pemicu dilakukan dengan cara tumpang susun (overlay) dan skoring dari parameter pemicu gerakan tanah longsor. Pendekatan secara statistik mendapatkan gambaran bahwa Provinsi Sumatera Utara berpotensi terhadap ancaman gerakan tanah longsor. Potensi ancaman gerakan tanah longsor tingkat sangat rendah sebesar 5,94 % dan tingkat rendah sebesar 74,23 %; sedangkan potensi ancaman longsor tingkat menengah dan tinggi sebesar 19,52 % dan 0,03 % dari luas total wilayah Provinsi Sumatera UtaraInitiation of potential hazard mapping of landslide movement in northern Sumatera becomes the main priority in disaster mitigation. Mitigation of landslide is expected to decrease and avoid the impact of landslide movement disaster. Concrete steps to anticipate improper land usage can be done by mapping its potential hazard. Disasters may arise as a result of human activities (anthropogenic) and natural factors. Approachment to the triggering factors is done by overlaying and scoring the parameters that trigger the landslides movement. Based on its statistical approach, we can conclude that North Sumatra province has the potential of landslide movement. The lowest potential of landslide movement is 5,94 % ; lower potential 74,23 % ; middle potential 19,52 % and the highest potential is 0,03% from the total area ofthe province of North Sumatr