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Pollution events extracted from the in situ observations of atmospheric CO2 and O2 mixing ratios at Hateruma Island (HAT, 24°N, 124°E) during the period from October 2006 and December 2008 are examined. The air mass origins for the pollution events are categorized by using back trajectory analysis, and the oxidative ratios (OR =-O2:CO2 molar exchange ratio) for selected pollution events are calculated. We find that there is a significant difference in the average oxidative ratios between events from China (OR = 1.14±0.12, n = 25) and Japan/Korea (OR = 1.37±0.15, n = 16). These values are in a good agreement with the national average oxidative ratios for the emissions from fossil fuel burning and cement production (FFBC) in China (ORFFBC = 1.11±0.03) and Korea/Japan (ORFFBC = 1.36±0.02). Compared with the observation, simulations of the atmospheric O2 and CO2 mixing ratios using Lagrangian particle dispersion models do a good job in reconstructing the average oxidative ratio of the pollution events originating in China but tend to underestimate for events originating in Japan/Korea. A sensitivity test suggests that the simulated atmospheric oxidative ratios at HAT are especially sensitive to changes in Chinese fuel mix. [ABSTRACT FROM AUTHOR]

Precise positioning of moving vehicles is necessary for many applications but the accuracy of global positioning system (GPS) is seriously affected in dense urban areas. This paper presents a general framework for matching such vehicle GPS traces with urban road networks based on a pipeline approach, where the matching is divided into several sequential stages. The GPS position points with inadequate satellite geometry are first filtered by common filters of fix and horizontal dilution of precision (HDOP). Then three advanced filters are developed to filter the deviant position points that have good satellite geometry but are not consistent with the vehicle motion model, i.e. velocity, angular velocity and heading changes. Finally, two curve-to-curve distance measurement algorithms - Hausdorff and Frechet are implemented to match these filtered trajectories with urban road networks. The examination of this approach is carried out using the vehicle track logging data in Sugimotocho station area of Osaka city, Japan. The results show that the pipelining of several filter algorithms can remove error position points on trajectories significantly. It also suggests that the Frechet algorithm outperforms Hausdorff by including the topology of road networks. [ABSTRACT FROM AUTHOR]

Abstract: To evaluate the effects of the regional pollutant emission and long-range transport from East Asia of nitrogen and sulfur pollutants on air quality at an inland suburban-forested site in northern Kyushu, western Japan, nitrogen and sulfur pollutants were characterized from May 2006 to April 2007 using an annular denuder system. The annual mean concentration of HNO3 (2.16μgm−3) at the study site was comparable to concentrations reported in urban areas. The HNO3 concentration had a diurnal variation, being higher in daytime and lower at night. The diurnal variation of wind direction suggests air pollutants emitted from the regional urban area were transported to the study site during the daytime and caused a higher HNO3 concentration. The HNO3 concentration was significantly higher in summer and spring than in winter. The annual mean concentrations of SO2 and nss-SO4 2− (6.52 and 7.70μgm−3, respectively) were higher than concentrations determined in other urban areas and forested areas near urban areas in Japan and other countries. The SO2 concentration was significantly higher in winter and spring than in summer. Backward trajectory analysis indicates the long-range transport from East Asia partly contributed to the higher concentrations of SO2 in winter and spring. In contrast, there were no statistical differences in the nss-SO4 2− concentrations among seasons, which could be explained by increased oxidation of SO2 to SO4 2− in summer. The value of sulfur conversion ratio (F s) being higher throughout the year at the study site (52.6%) than values determined in urban sites and there being no diurnal variation of F s indicates the long-range transport of nss-SO4 2− not only from East Asia but also from other areas including Japan. The equivalent ratio of NH4 + and nss-SO4 2− at the study site (0.96±0.22) indicates that acidic sulfate is neutralized by NH3, existing mainly as (NH4)2SO4 in fine particles. On the other hand, NH4NO3 had scarcely formed at the study site, unlike the case for urban areas. Ca2+ and Na+ are suggested to be the counter ions of NO3 − in coarse particles, which is similar to the situation for the sites where the concentration of NH3 is insufficient for NH4NO3 to form. [Copyright &y& Elsevier]

Total gaseous mercury (TGM) and carbon monoxide (CO) were measured every 5min and hourly, respectively, in Seoul, Korea, from February 2005 through December 2006. The mean concentrations of TGM and CO were 3.44±2.13ngm−3 and 613±323ppbv, respectively. TGM and CO concentrations were highest during the winter and lowest during the summer. In total, 154 high TGM concentration events were identified: 86 were classified as long-range transport events and 68 were classified as local events. The TGM and CO concentrations were well correlated during all long-range transport events and were weakly correlated during local events. Five-day backward trajectory analysis for long-range transport events showed four potential source regions: China (79%), Japan (13%), the Yellow Sea (6%), and Russia (2%). Our results suggest that measured ΔTGM/ΔCO can be used to identify long-range transported mercury and to estimate mercury emissions from long-range transport. [Copyright &y& Elsevier]

The purpose of this paper is to optimize helicopter flight trajectories to reduce ground noise in the landing approach using an optimization technique and to conduct flight experiments to confirm the effectiveness of the optimal solutions. The Japan Aerospace Exploration Agency has thus far measured helicopter noise under various flight conditions. This study builds a noise model of the helicopter in which the level of noise generated from a point noise source is a function of the flight path angle and bank angle. Then, we define optimal control problems that minimize the noise levels measured at points on the ground surface using equations of motion of 3 degrees of freedom for three-dimensional flight, and obtain the optimal controls for some flight constraints and wind conditions. The obtained optimal flights avoid the flight path angle that generates a great deal of noise and skirt the measurement points; these optimal flights are different from the conventional flight. Finally, this study verifies the validity of the optimal flight patterns by means of flight experiments with an experimental Japan Aerospace Exploration Agency helicopter. The actual flights following the optimal flights result in noise reduction and prove the effectiveness of the optimization. [ABSTRACT FROM AUTHOR]

Solar Photovoltaics (PV) is seen as one of the renewable energy technologies that could help reduce the world's dependence on fossil fuels. However, since it is dependent on the sun, it can only generate electricity in the daytime, and this restriction is exacerbated in electricity grids with high PV penetration, where solar energy must be curtailed due to the mismatch between supply and demand. This study conducts a techno-economic analysis to present the cost-optimal storage growth trajectory that could support the dynamic integration of solar PV within a planning horizon. A methodology for cost-optimal assessment that incorporates hourly simulation, Monte Carlo random sampling, and a proposed financial assessment is presented. This approach was tested in Japan's southernmost region since it is continuously increasing its solar capacity and is at the precipice of high PV curtailment scenario. The results show the existence of a cost-optimal storage capacity growth trajectory that balances the cost penalty from curtailment and the additional investment cost from storage. This optimal trajectory reduces the impact of curtailment on the energy generation cost to manageable levels and utilizes more solar energy potential that further reduces CO 2 emissions. The results also show that the solar capacity growth rate and storage cost significantly impact the optimal trajectory. The incorporation of the Monte Carlo method significantly reduced the computational requirement of the analysis enabling the exploration of several growth trajectories, and the proposed financial assessment enabled the time-bound optimization of these trajectories. The approach could be used to calculate the optimal growth trajectories in other nations or regions, provided that historical hourly temperature, irradiance, and demand data are available. [ABSTRACT FROM AUTHOR]