The Effect of Car Free Day (CFD) on Pollutant Emissions at Alternative Roads (Case Study: RE Martadinata Street, Bogor City)

Car Free Day (CFD) is a social campaign aimed to reduce the dependence of people on vehicle uses, which occurs once per week in Bogor. The idea intends to decrease the vehicle emissions. However, CFD is often to cause a new problem like the congestions, which are found on the nearby alternative roads, as happened in RE Martadinata Street, Bogor City. This study aims to compare the emission load and the concentrations of pollutants in ambient air during CFD (06.00-09.00 am) and non-CFD days in alternative road. We measured the following pollutants: CO, HC, NOx, PM10 and SO2. This research first applied Fixed-Box Model to estimate concentration of pollutants, then we used the Finite Length Line Source (FLLS) to estimate dispersion of pollutants. The results showed that there was no substantial difference in pollutant emissions between CFD and non-CFD days. But if we separate between weekdays and weekend, our analysis revealed that emissions during the weekend are bigger than that of weekdays. This was consistent with an increase of number of vehicles during the weekends by 17.2%. Based on our analysis, motorcycle contributes to an increased of CO, HC, PM10 pollutants, whereas SO2 and NOx pollutants were generated by cars. Our findings suggest that a short time of CFD does not contribute a lot to reduce the emissions

Prediksi Awal Musim Hujan di Jawa Menggunakan Data Luaran Regional Climate Model Version 3.1 (RegCM3)

Monsoon onset information plays an important role in setting up planting strategy for achieving optimum yield. This study aimed to develop forecasting model for the monsoon onset in main rice growing area of Java used Regional Climate Model Version 3.1 (RegCM3). The forecasting models of the monsoon onset and September-Oktober-November (SON) rainfall data were developed using regression model that have the highest coefficient determination and the models were tested using likelihood ratio test. It was found that the forecasting models of the monsoon onset and September-Oktober-November rainfall data were polynomial orde 2 or cuadratic that have coefficient determination 69%, 74%, 80% and 86%. Likelihood ratio test found that RegCM3 rainfall data was not significantly different with observation rainfall data (α = 0.05). Onset in Java between 25th until 34th of 10-days period (early September until early December)

KONDISI ATMOSFER PADA KEJADIAN BANJIR DESEMBER 2007 SAMPAI JANUARI 2008 DI KABUPATEN BOJONEGORO

Banjir merupakan salah satu bencana yang menimbulkan kerugian bagi manusia. Bencana tersebut biasanya didahului oleh curah hujan yang tinggi (lebat) dan lama. Proses terjadinya hujan yang tinggi dan lama memerlukan kondisi atmosfer yang mendukung seperti . Tujuan utama penelitian ini adalah menjelaskan kondisi atmosfer pada saat banjir di Kabupaten Bojonegoro tanggal 26 Desember 2007 sampai 7 Januari 2008. Hasil analisis menunjukkan bahwa kondisi atmosfer saat banjir tidak stabil, kandungan uap air tinggi, pengangkatan massa udara intensif dan kecepatan angin rendah. Kondisi tersebut cukup potensial dalam menyebabkan hujan yang lebat, meskipun kondisi atmosfer tersebut belum termasuk kategori ekstrim. Dengan demikian banjir tersebut tidak hanya dipengaruhi oleh kondisi atmosfer setempat tetapi dipengaruhi juga oleh kondisi atmosfer sekitarnya dan kondisi permukaan.   Flood is one of the disasters that cause harm to humans. That disaster is usually preceded by heavy and long-term rainfall. The occurrence of high and long-term rainfall requires atmospheric conditions that supported it. The main objective of this study is to explain the atmospheric conditions while flood event in Bojonegoro on December 26th 2007 until January 7th 2008. The analysis showed that the atmospheric conditions are unstable during floods, high moisture content and the removal of intensive air mass and low wind speeds. The atmospheric condition during the flood was sufficient to support the heavy rain but not in extreme categories. Therefore, the flood affected by atmospheric conditions in surrounding area and surface condition in that area