• 한국대기환경학회지
• /
• 제32권4호
• /
• pp.394-407
• /
• 2016

The spatial air pollution distribution of the Ulsan metropolitan region (UMR) was analyzed using monitoring data and high-resolution numerical simulations. A three-year (2011~2014) analysis for the average concentrations from the 13 air quality monitoring sites in the UMR showed that $SO_2$ and $PM_{10}$ levels in industrial regions were much higher than those in other regions, whereas spatial differences of $NO_2$ and CO concentrations were not significant. In particular, elevated $O_3$ concentrations were clearly found at urban sites near petrochemical complex area. Results from high-resolution simulations by CMAQ model performed for four months of 2012 showed large spatial variations in grid-average pollutant concentrations between industrial areas and other areas in the UMR, which displayed significant changes with wind pattern by season. It was noted that the increases of $SO_2$ and $PM_{10}$ levels were limited in costal industrial areas or over the area nearby the sea in all seasons. Modeled $O_3$ concentrations were quite low in industrial areas and main urban roads with large $NO_x$ emissions. However, the model presented that all pollutant concentrations were significantly increased in the urban residential areas near the industrial complexes in summer season with increase of southerly wind.

• 한국대기환경학회지
• /
• 제18권2호
• /
• pp.113-126
• /
• 2002

This study was carried out to evaluate the temporal (daily, weekly, and seasonal) variations of volatile organic compounds (VOCs) concentrations at a road-side site in a heavy-traffic central area of Metropolitan Taegu. Ambient air sampling was undertaken continuously for 14 consecutive days in each of four seasons from the spring of 1999 to the winter of 2000. The VOC samples were collected using adsorbent tubes, and were determined by thermal desorption coupled with GC/MS analysis. A total of 10 aromatic VOCs of environmental concern were determined, including benzene, toluene, ethylbenzene, m＋p-xylenes, styrene, o-xylene, 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, and naphthalene. Among 10 target VOCs, the most abundant compounds appeared to be toluene (1.5 ∼ 102 ppb) and xylenes (0.1 ∼ 114 ppb), while benzene levels were in the range of 0.3 ∼6 ppb. It was found that the general trends of VOC levels were significantly dependent on traffic conditions at the sampling site since VOC concentrations were at their maximum during rush hours (AM 7∼9 and PM 7 ∼9). However, some VOCs such as toluene, xylenes, and ethylbenzene were likely to be affected by a number of unknown sources other than vehicle exhaust, being attributed to the use of paints, and/or the evaporation of solvents used nearby the sampling site. In some instances, extremely high concentrations were found for these compounds, which can not be explained solely by the impact of vehicle exhaust. The results of this study may be useful for estimating the relative importance of different emission sources in large urban areas. Finally, it was suggested that the median value might be more desirable than the arithmetic mean as a representative value for the VOC data group, since the cumulative probability distribution (n=658) does not follow the normal distribution pattern.

• 한국환경과학회지
• /
• 제7권3호
• /
• pp.335-348
• /
• 1998

The intensive meteorological observations including pibal balloon at Ungcheon, airsonde and 10m meteorological tower observations at Gulup-Do, where are located In the western coastal region, are taken to Investigate the characteristics of the upper and lower atmospheric structure and the local circulation pattern during the period of 17 to 22 September 1996. The diurnal variations of weather elements(i.e. air temperature, humidity, pressure, and Und speeds at Gulup-Do are analyzed and discussed with those at four inland meteorological stations. The vertical profiles of wind vector, ortho- gonality(Ω), and shear obtained from the pibal obsenrations are also presented to examine the change of wand structure according to the synoptic-scale pressure system's movement. The diurnal temperature changes at Gulup-Do are more sensitive than that of Inland meteorological stations In case of the mow of southwesterlies but are not dominant due to the ocean effect under the Influence of relatively cold northerlies. A well defined mixed layer Is developed from the 500m to the maximum 1700m with a significant capping Inversion layer on the top of it. It can be found from the vertical profiles of wind vector that the wind become generally strong at the interface heights between cloud lay- ers and non-cloud layers. The maximum Und shear Is appeared at the bel각t where the varlauon of wand direction Induced by the passage of synoptic-scale pressure system Is accompanied with the In- crease of Und speed. Based on the wind orthogonality, the change of wind direction with height is more complicated In cloudy day than In clear day. In case of a fair weather, the change of wand direction is showed to be at around 2km.

• 한국환경농학회지
• /
• 제28권1호
• /
• pp.82-85
• /
• 2009

This study was performed to investigate if elevated $CO_2$ affects the residue pattern of $^{14}C$ in the soil environment after $^{14}C$-carbaryl treatment $^{14}C$-carbaryl was applied on the rice plant-grown greenhouse soil exposed to atmospheric and elevated $CO_2$ conditions. $^{14}C$-radioactivity was measured in the rhizospheric soil and rice straw samples six months after $^{14}C$-carbaryl application. Significantly high radioactivity was observed in the soil exposed to atmospheric $CO_2$ as compared to that in the soil exposed to elevated C(h. Background level of radioactivity was observed in rice plant samples. These observations suggest the possibility that elevated $CO_2$ may affect residual radioactivity of $^{14}C$-carbaryl in the soil rather than that in the plant.

• 한국대기환경학회지
• /
• 제26권4호
• /
• pp.420-431
• /
• 2010

The water-soluble components have been analyzed from the total suspended particulate (TSP) collected at Gosan site of Jeju Island for ten years (1997~2006), and the long-term variations of ionic constituent concentrations have been investigated in order to understand the pollution characteristics of atmospheric aerosols. Their mean concentrations were in the order of nss-${SO_4}^{2-}$ > $Na^+$ > ${NO_3}^-$ > $Cl^$ > ${NH_4}^+$ > nss-$Ca^{2+}$ > $K^+$ > $Mg^{2+}$. The ${NO_3}^-$ concentrations had increased somewhat smoothly compared to those of ${SO_4}^{2-}$ for the past 10 years, possibly indicating the recent energy consumption pattern changes in China. The concentrations of ionic aerosol components showed mostly higher values during the Asian Dust storm periods, and the concentration ratios of nss-$Ca^{2+}$, ${NO_3}^-$, and nss-${SO_4}^{2-}$ between the Asian Dust and Non-Asian Dust periods were 6.9, 2.4, and 1.3, respectively. The anthropogenic nss-${SO_4}^{2-}$, ${NO_3}^-$, ${NH_4}^+$ and the soil originated nss-$Ca^{2+}$ components showed high concentrations as the air parcels were moved from the Asia continent, on the other hand, their concentrations were relatively low as moving from the Northern Pacific into the Gosan area.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
• /
• pp.43-48
• /
• 1998

Prior to launch, simulated radiances of the Ocean Scanning Multispectral Imager (OSMI) will be very useful to guess the real imagery of OSMI and to check the data processing system for OSMI. The data processing system for OSMI which is one sensor of Korea Mult i - Purpose Satellite (KOMPSAT) scheduled for launch in 1999 is being developed based on the SeaWiFS Data Analysis System (SeaDAS). Such a simulation should include the spectral bands, orbital and scanning characteristics of the OSMI and KOMPSAT spacecraft. The simulation is also very helpful for finding and preparing for problem areas before launch. This paper describes a method to create simulated radiances of the OSMI over the oceans. Our method for constructing a simulated OSMI imagery is to propagate a KOMPSAT orbit over a field of Coastal Zone Color Scanner (CZCS) pigment values and to use the values and atmospheric components to calculate total radiances. A modified Brouwer - Lyddane model with drag was used for the realistic orbit prediction, the CZCS pigment data were used to compute water - leaving radiances, and a variety of radiative transfer models were used to calculate atmospheric contributions to total radiances detected by OSMI. Imagery of the simulated OSMI total radiances for 6 nominal bands was obtained. As expected, water - leaving radiances were only a small fraction of total radiances and sun glint contaminations were observed near the solar declination. Therefore, atmospheric correction is very important in the calculation of pigment concentration from total radiances. Because the imagery near the sun's glitter pattern is virtually useless and must be discarded, more advanced mission planning will be required.

• Applied Biological Chemistry
• /
• 제16권2호
• /
• pp.94-98
• /
• 1973

1. 품종은 노지에서 재배한 복수2호를 사용하였으며 1971년과 1972년 2회에 걸쳐 Tomato 과실의 성숙시기별 호흡량변황 및 저장중 성분변화에 대하여 조사하였다. 2. 환경압력조절에 의한 Tomato 과실의 호흡억제효과는 SAP 구중 660 Torr. 구가 가장 효과적이었다. 3. 성장중 성숙시기별로 채취한 Tomato의 호흡량 변화는 각채취시기별로 차이가 있었으며 Tomato의 일대에 있어서 시기별 숙기에 이른 과실을 경과일수에 따라 호흡량을 조사하면 전체적으로 호흡량의 증감이 sigmoid 형으로 나타났으며 하나의 climacteric pattern을 나타내 주고 있다. 4. 성장중 성숙시기별로 채취한 Tomato 과실의 환경압력변화에 의한 영향은 어느시기에서나 NAP구보다 SAP구의 호흡량이 적었으며 전 기간중 동일한 경향으로 호흡억제 효과가 있었다. 5. 저장중 Tomato 과실의 중량변화는 NAP 구가 SAP 구보다 현저하며 산, 당 및 Vitamine-C의 변화에 있어서는 SAP구가 NAP구 보다 감소율이 적었다.

• 한국대기환경학회:학술대회논문집
• /
• 한국대기환경학회 2002년도 추계학술대회 논문집
• /
• pp.343-343
• /
• 2002

This study examines the influence of long-range transport of dust particles and air pollutants on both local/regional DMS oxidation chemistry and the distribution of sulfur compounds at Jeju Island (33.17$^{\circ}$ N. 126.10$^{\circ}$ E) during the Asian dust-storm(ADS) period in April 2001. The atmospheric concentrations of these sulfur species were measured at a ground station on Jeju Island. Korea as Part of the ACE-Asia intensive operation. Three ADS events were observed during the periods of 10-12, 13-14. and 25-26 April. respectively. The concentrations of DMS and CS$_2$ were higher during the ADS period than during the non-Asian-dust-storm (NADS) period. Conversely. a difference in SO$_2$ levels during the ADS period was not distinguishable from those during the NADS period. The diurnal variation pattern of DMS observed was largely different from that in the remote marine boundary layer. DMS loss by NO$_3$ in the atmospheric boundary layer was dominant due to significantly high NOx levels influenced by the long-range transport of pollutants from East Asia to Jeju Island The DMS maximum during the ADS period was observed in the late afternoon. The oceanic fluxes of DMS during the ADS and NADS periods were estimated to be 5.7$\pm$2.3 and 2.9 (+2.8/-1.5) mole m$^{-2}$ day$^{-1}$ . respectively. The contribution of oxidized DMS to SO$_2$ levels at Jeju Island during the study period was found to be insignificant.

• 한국환경과학회지
• /
• 제24권6호
• /
• pp.827-840
• /
• 2015

This study analyzed a correlation between South China Sea summer (June to September) monsoon (SCSSM) and the ENSO for the last 32 years (1979 to 2010). There was a correlation that the higher (lower) the SST in the $Ni{\tilde{n}}o-3.4$ region was, the weaker (stronger) the SCSSM intensity was. To identify the reason for this correlation, a difference of means between 8 El $Ni{\tilde{n}}o$ years and 8 La $Ni{\tilde{n}}a$ years (June to September). The analysis on the difference between two groups with respect to the 850 hPa stream flows showed that there were anomalous huge cyclones in the subtropical Pacific in the both hemispheres so that cold and dry anomalous northerlies were strengthened in the South China Sea relatively while anomalous westerlies were strengthened from the Maritime Continent to the off the coast of Chile. The analysis on the difference between two groups with respect to the 200 hPa stream flows showed that the opposite anomalous pressure system pattern to that in the 850 hPa stream flows were shown. In the subtropical Pacific of the both hemispheres, anomalous anticyclones existed so that anomalous easterlies were strengthened from the Maritime Continent to the equatorial central Pacific. Considering the anomalous atmospheric circulations in the upper and lower layers of the troposphere, upward airflows from the equatorial central and eastern Pacific were downward in the South China Sea and the Maritime Continent, which was a structure of anomalous atmospheric circulations. This means that the Walker Circulation was weakened and it was a typical structure of atmospheric circulations revealed in El $Ni{\tilde{n}}o$ years.

• 한국환경과학회지
• /
• 제7권2호
• /
• pp.177-184
• /
• 1998

1981년부터 1990년까지 10년간 발생한 274개의 호우사례를 분류하여,한반도에서 호우시에 나타나는 강수량의 공간분포를 여섯 종류로 나누고 각각의 정관적 특성을 분석하였다. 첫때, 강하게 발달한 지표 저기압에 연관되어 발생하는 호우보다 상, 하층 제트를 동반한 채 발달중인 저기압에 연관되어 발생하는 호우가 많다. 둘째, 재부분의 호우역은 하층 제트의 위치와 방향 그리고 지표 온나전선의 위치에 연관되어 있다. 셋째, 500hPa 면의 저기압 중심이나 기압골의 위치가 서쪽으로 멀어질수록 한반도에어 호우는 고위도에서 발생하는 경향이 있다. 넷째, 한반도에 호우를 초래하는 500hPa의 저기압 중심은 하계몬순의 발달을 따라 서쪽으로 자리잡는 경향이 있으나 해마다 차이가 있다.차이가 있다.