• Journal of Korean Society for Atmospheric Environment
• /
• v.14 no.5
• /
• pp.479-490
• /
• 1998

The concentrations of ten inorganic (sodium, chloride, sulfate, ammonia, etc.) and three organic (acetate, formate, and MSA) ions associated with airborne particulate matter were measured from Cheju Island, Korea during the three field intensive campaigns conducted in (1) Sept./oct. 1997 (fall), (2) Dec. 1997 (winter), and (3) April 1998 (spring). The results of our measurements indicated that the concentration levels of most ionic species were decreasing significantly across the three experimental periods. The patterns of concentration reduction were clear as the sum of all cation and anion species changed dramatically across those periods such as 294> 144 > 65 and 193 >96>74 nequiv/m3, respectively. The changes were best explained in terms of the wind rose patterns of the study site. Since our sampling spot is located on the western-end point of Cheju Island, it is likely to reflect the effects of diverse sources such as natural, marine processes during NW and local non-maritime ones during SE winds. .Hence, the periodical changes in ionic concentrations may be accounted for by the comparable changes in wind direction. To further investigate environmental characteristics of these ionic components, correlation analysis was conducted not only between meteorological and ion data but between different ion-pairs. The results of these analyses confirm that the concentration levels of ionic species are strongly affected by wind speed and temperature and that there are certain patterns between ion species to which such effects apply. In light of the significance of the wind rose patterns in the area, we further extended these analyses into four data groups that were divided on the basis of wind direction. The results of these analyses showed that the strength of correlations between important pairs (e.g.:. between windspeed and most of major inorganic species including sodium and chloride) can be ranked on the distribution of major ions are very diverse, depending on data grouping scheme for such analysis. The results of this study thus suggest that environmental behavior of chemical components be analyzed in various respects, rather than simple standard, especially if measurements are made in complex environmental condition under which both natural and anthropogenic effects are competing each other.

• Journal of Korean Society for Atmospheric Environment
• /
• v.25 no.4
• /
• pp.289-303
• /
• 2009

The chemical and meteorological effects on the concentration variations of ozone ($O_3$) were evaluated based on the intensive air quality measurement (5 pollutants and aromatic volatile organic compounds (AVOCs)) in and out-side an urban valley during spring and summer of 2006. The 5 pollutants measured in the study area include $O_3$, $NO_2$, NO, $PM_{10}$, and CO; the AVOCs include benzene (BEN), toluene (TOL), ethylbenzene (EB), m,p-xylene (MPX), and o-xylene (OX). For the purpose of this study, study areas were classified into two categories: valley area (VA) with a semi-closed topography covering a number of industrial complex, public building, and mountains and non-valley area (NVA) surrounding the suburban and residential areas. In general, the mean concentration levels of most pollutants (except for $PM_{10}$) in the VA were higher than those in the NVA. It was found that the average $O_3$ increase in the VA during spring might result from the combined effects such as the photochemical production from diverse anthropogenic sources and the $O_3$ accumulation due to geographical features (e.g., the semi-closed topography) and wind conditions (e.g., a low wind speed). In addition, the nocturnal $O_3$ increase in the VA during spring was primarily caused by local wind conditions (e.g., mountain and valley winds) with the low wind speed (approximately $1{\sim}2\;m\;s^{-1}$). On the other hand, the $O_3$ difference between the two areas during summer might be because of the photo-chemical production with the $O_3$ precursors (especially the AVOCs) rather than the contribution of wind conditions.

• Journal of Korean Society for Atmospheric Environment
• /
• v.32 no.3
• /
• pp.329-341
• /
• 2016

Pohang is a well-known industrial city in Korea with a large steel-industrial complexes. The biggest environmental issue in the city is associated with fine particulate matter (hereinafter, $PM_{10}$). The concentration of $PM_{10}$ is generally dependent on the local emission sources and meteorological conditions. Iron and steel industrial complexes are likely serious pollution sources of $PM_{10}$ in Pohang. In this study, daily $PM_{10}$ data from a large database from the year of 2000 to 2012 were statistically analyzed, together with meteorological data. The average concentrations of $PM_{10}$ were evaluated according to the frequency of Asian dust, haze, mist, and fog. The number of days exceeding short-term standard for $PM_{10}$ were also examined, taking into consideration of weather conditions. It was found that the concentration of $PM_{10}$ was reduced about 18% to 26% because of precipitation. In addition, the effects of wind direction and wind speed on the $PM_{10}$ concentrations were investigated.

• Journal of Environmental Health Sciences
• /
• v.30 no.5 s.81
• /
• pp.417-426
• /
• 2004

We investigate changing characteristics and concentration distribution of ambient air quality using data from which obtained local ambient air monitoring network and local meterological measuring sites in Gwangju area from January to December in 2003. Sulfur dioxide ($SO_2$) showed that increase from 8 AM and decrease in 6 PM but, it was not drastically changed concentration. it also 0.010 ppm in 1995 from at this time it's decrease step by step and than some constant in year 2001 to 2003. Nitrogen dioxide ($NO_2$) concentration was showed highest peak in 10 AM and increase again at 6 PM. And also it showed peak concentration (0.026 ppm) in 2001 and decreased from after that times. Ozone was showed peak concentration in 1 PM and Nitrogen dioxide was ditto in 10 AM from this data, we can conclude that this two article ws showed chemical reaction by 3 to 5 hours. There was no case of Ozone alarm in Gwangju area since 1995, but it showed highest ozone concentration (over 0.070 ppm) in May and June of the year and 2 to 4 PM of the day and sometimes it showed increase at the dawn. Ozone product optimum condition was that air temperature is over $25^{\circ}C$, no rain and increase solar radiation (over $20MJ/m^2$) and no wind or below 2.0 m/s wind speed.

• Journal of the Korean earth science society
• /
• v.24 no.6
• /
• pp.533-548
• /
• 2003

The prevailing wind phenomenon around Pohang in winter was investigated by using surface and vertical observatory datas and a numerical simulation was carried out to analyse this phenomenon using RAMS. Direction of the prevailing wind was westerly at upper atmosphere. However, near the surface, southwestern wind prevailed in winter. Using the RAMS to simulate a winter wind system numerically, it was found out that this phenomenon was strongly affected by the geographical features such as directions of coastline and low level valley, and distributions of land and sea. To investigate the accuracy of the model results, wind speed, temperature and wind direction of typical continuous southwestern wind occurring days were compared with observation data. Analyzing the characteristics of local circulation system was very hard because of horizontally sparse observation data. But from the result above, a numerical simulation using the RAMS, which satisfies the spatial high resolution, will provide more accurate results.

• Wind and Structures
• /
• v.28 no.2
• /
• pp.129-140
• /
• 2019

Accurately simulating the wind field of large-scale region, for instant urban areas, the locations of large span bridges, wind farms and so on, is very difficult, due to the complicated terrains or land surfaces. Currently, the regional wind field can be simulated through the combination of observation data and numerical model using observation-nudging in the Weather Research and Forecasting model (WRF). However, the main drawback of original observation-nudging method in WRF is the effects of observation on the surrounding field is fully mathematical express in terms of temporal and spatial, and it ignores the effects of terrain, wind direction and atmospheric circulation, while these are physically unreasonable for the turbulence. For these reasons, a spatial correlation-based observation-nudging method, which can take account the influence of complicated terrain, is proposed in the paper. The validation and comparation results show that proposed method can obtain more reasonable and accurate result than original observation-nudging method. Finally, the discussion of wind field along bridge span obtained from the simulation with spatial correlation-based observation-nudging method was carried out.

• Journal of Environmental Impact Assessment
• /
• v.15 no.4
• /
• pp.237-247
• /
• 2006

In case of studied area located around the sea, the data measured from the regional meteorological office is highly different from the local weather data because the diffusivity of fugitive dust varies considerably with meteorological conditions. Especially, it is very difficult to predict the amount of fugitive dust accurately as wind speed remains high frequently. In this study, the fluxes of suspended particulates as a function of the friction velocity were applied to consider the effect of wind speed on the amount of fugitive dust generated from the reclamation site. The amount of fugitive dust estimated as mentioned above was simulated by using ISCST3 model. As a result, in case of using only the Fugitive Dust Formula which is usually used in Environment Impact Assessment, the predicted $PM_{10}$ concentrations with points were $43.4{\sim}67.8{\mu}g/m^3$. However, in case of applying to the flux of suspended particulates, the predicted values of $PM_{10}$ with points were $43.3{\sim}69.1{\mu}g/m^3$, $49.5{\sim}90.4{\mu}g/m^3$ and $76.0{\sim}182.6{\mu}g/m^3$ with the wind speeds of 4.4, 5.8 and 7.7m/s, respectively. It could be possible to predict the amount of fugitive dust accurately because these predicted values were similar to the measured values. Consequently, we can establish alternatives for reduction of fugitive dust in this area damaged by fugitive dust which is caused by wind.

• Journal of Environmental Science International
• /
• v.22 no.9
• /
• pp.1213-1226
• /
• 2013

$PM_{10}$ concentration is related to the meteorological variables including to local and synoptic meteorology. In this study the $PM_{10}$ concentrations of Busan in 2007~2011 were analyzed and the days of yellow sand or rainfall which is more than 5 mm were excluded. The sections of $PM_{10}$ concentration were divided according to 10-quantiles, quartiles and 90-quantiles. The 90-quantiles of daily $PM_{10}$ concentration were selected as high concentration dates. In the high concentration dates the daily mean averaged cloudness, mean daily surface wind speed, daily mean surface pressure and PBL height were low and diurnal variation of surface pressure and daily maximum surface temperature were high. When the high $PM_{10}$ dates occurred, the west and south wind blew on the ground and the west wind blew strongly on the 850 hPa. So it seemed that long range transboundary air pollutants made effects on the high concentration dates. The cluster analysis using Hysplit model which is the backward trajectory was made on the high concentration dates. As a result, 3 clusters were extracted and on the short range transboundary cluster the daily mean relative humidity and cloudness were high and PBL height was low.

• Journal of Korean Society for Atmospheric Environment
• /
• v.27 no.6
• /
• pp.791-804
• /
• 2011

Numerical simulations were carried out to investigate the impact of PBL (Planetary boundary layer) scheme implemented in WRF on the result of meteorological fields and CMAQ modeling. 25-day period, representing high ozone concentration, was selected for the simulations. The three WRF domains covered East Asia region, Korean Peninsula and Seoul metropolitan area. The sensitivity of WRF-CMAQ modeling to the various PBL schemes was assessed and quantified by comparing model output and against observation from the meteorological and the air quality monitoring network within the domain. The meteorological variables evaluated included temperature, wind speed and direction over surface sites and upper air sounding sites. The CMAQ variables included gaseous species $O_3$ and $NO_x$ over monitoring stations. Although difference of PBL schemes implemented in WRF, they did not appreciably affect the WRF and CMAQ performance. There are partially differences between non-local and local mixing scheme, but are not distinct differences for the results of weather and air quality. It is suggested that impact of parameterization of vertical eddy diffusivity scheme in CMAQ also need to be researched in the future study.

• Atmosphere
• /
• v.32 no.2
• /
• pp.119-133
• /
• 2022

From 2015 to 2021, high-concentration fine dust episodes with a daily average PM_2.5 concentration of 50 ㎍ m^-3 or higher were selected and classified into 3 types [long range transport (LRT), mixed (MIX) and Local emission and stagnant (LES)] using synoptic chart and backward trajectory analysis. And relationships between the fine particle data (PM_2.5 and PM₁₀ concentration and PM_2.5/PM₁₀ ratio) and meteorological data (PBLH, Ta, WS, U-wind, and Rainfall) were analyzed using hourly observation for the classification episodes on the Korean Peninsula and the Seoul metropolitan area (SMA). In LRT, relatively large particles such as dust are usually included, and in LES, fine particle is abundant. In the Korean peninsula, the rainfall was relatively increased centered on the middle and western coasts in MIX and LES. In the SMA, wind speed was rather strong in LRT and weak in LES. In LRT, rainfall was centered in Seoul, and in MIX and LES, rainfall appeared around Seoul. However, when the dust cases were excluded, the difference between the LRT and other types of air quality was decreased, but the meteorological variables (Ta, RH, Pa, PBLH, etc.) were further strengthened. In the case of the Korean Peninsula, it is difficult to find a clear relationship because regional influences (topographical elevation, cities and coasts, etc.) are complexly included in a rather wide area. In the SMA, it is analyzed that the effects of urbanization such as the urban heat island centered on Seoul coincide with the sea and land winds, resulting in a combination of high concentrations and meteorological phenomena.