• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2008년도 춘계학술대회 논문집
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• pp.447-449
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• 2008

• 한국전자파학회논문지
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• 제19권6호
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• pp.698-705
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• 2008

전자파가 대기를 통과할 때 대기를 형성하고 있는 다양한 요인들에 의해 그 특성이 변동하게 된다. 전파 특성에 영향을 미치는 대기의 주요 요인으로는 수증기, 안개, 산소와 같은 대기 입자, 강우, 강설 및 그 외 여러 종류의 에어로졸을 들 수 있으며, 이러한 것들은 지형 및 지역적 특성에 따라 다르게 분포한다. 따라서 대기 환경에서의 전파 특성을 예측하기 위해서는 주어진 환경에 대한 기온, 습도, 기압, 풍속, 에어로졸 및 강우율 등의 통계적 분석이 중요하다. 본 논문에서는 국내 대기 환경에 대한 통계적 분석을 수행하였으며, 이를 바탕으로 국내 대기 환경에서의 전파 특성을 분석하였다.

• 대한원격탐사학회지
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• 제29권6호
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• pp.663-670
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• 2013

Total Vertical Column Density (VCD) of $NO_2$, a key component in air quality and tropospheric chemistry was measured using a ground-based instrument, Pandora, in Seoul from March 2012 to October 2013. The $NO_2$ measurements using Pandora were compared with those obtained by satellite remote sensing from Ozone Monitoring Instrument (OMI) where the intercomparison characteristics were analyzed as a function of measurement geometry, cloud amount and aerosol loading. The negative biases of the OMI $NO_2$ VCD were larger when cloud amount and Aerosol Optical Depth (AOD) were higher. The correlation coefficient between $NO_2$ VCDs from Pandora and OMI was 0.53 for the entire measurement period, whereas the correlation coefficient between the two was 0.74 when the cloud amount and AOD were low (cloud amount<3, AOD<0.4). The low bias of OMI data was associated with the shielding effect of the cloud and the aerosols.

• Asian Journal of Atmospheric Environment
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• 제5권2호
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• pp.105-112
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• 2011

In order to investigate the effects of local and synoptic meteorological conditions on urban scale particulate air pollutants observed over the Busan coastal area, power spectrum analysis was applied to observed particulate matter with an aerodynamic diameter $\leq10\;{\mu}m$ ($PM_{10}$) for the period from 1 October, 1993 to 31 December, 2004. Fast Fourier Transform (FFT) analysis was used to obtain the hourly mean observed $PM_{10}$ concentrations to identify different periodicity scales of $PM_{10}$ concentrations. The results showed that, aside from the typical and well-known periodicities such as diurnal and annual variations caused by anthropogenic influences, three other significant power spectral density peaks were identified: 7-day, 21-day and 2.25-year periodicities. Cospectrum analysis indicated that the seven-day variations were closely related to the synoptic meteorological conditions such as weak wind speed, which are relevant to the stagnant high pressure system slowly passing through the Korean Peninsula. The intra-seasonal 21-day variation was negatively correlated with wind speed but was consistently positively correlated with relative humidity, which is related to aerosol formation that can be achieved as a result of the hygroscopic characteristics of aerosols. However, the quasibiennial 2.25-year variation was correlated with the frequency of Asian dust occurrence, the periodicities of which have been recorded inter-annually over the Korean Peninsula.

• 한국대기환경학회지
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• 제32권1호
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• pp.57-66
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• 2016

Aerosol optical thickness (AOT) and ${\AA}ngstr{\ddot{o}}m$ exponents were monitored at the KIU site ($N35.91^{\circ}$, $E128.80^{\circ}$) during the continuous observation period of 5 November 2010~19 March 2013 using a Microtops-II handheld munti-wavelenth radiometer. Comparisons of AOT values from the Microtops-II with the Sun-sky radiometer data from the Aerosol Robotic Network (AERONET) showed very good agreements: correlation coefficients are lies between 0.98 and 0.99, slopes range from 0.98 to 1.01, and intercepts are smaller than 0.008 at five wavelengths (380 nm, 440 nm, 500 nm, 675 nm, 870 nm). During the observation period, the Microtops-II AOT and ${\AA}ngstr{\ddot{o}}m$ exponents are ${\tau}_{500}=0.560{\pm}0.351$, ${\alpha}_{500-870}=1.135{\pm}0.445$. Fine mode aerosols appear to dominate in the study region with significant contributions from small particles.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2004년도 GIS/RS 공동 춘계학술대회 논문집
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• pp.241-246
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• 2004

The ocean signal that reaches the detector of an imaging system after multiple interactions with the atmospheric molecules and aerosols was retrieved from the total signal recorded at the top of the atmosphere (TOA). A simple method referred to as 'Path Extraction' applied to the Landsat-TM ocean imagery of turbid coastal water was compared with the conventional dark-pixel subtraction technique. The shape of the path-extracted water-leaving radiance spectrum resembled the radiance spectrum measured in-situ. The path-extraction was also extended to the SeaWiFS ocean color imagery and compared with the standard SeaWiFS atmospheric correction algorithm, which relays on the assumption of zero water leaving radiance at the two NIR wavebands (765 and 865nm). The path-extracted water-leaving radiance was good agreement with the measured radiance spectrum. In contrast, the standard SeaWiFS atmospheric correction algorithm led to essential underestimation of the water-leaving radiance in the blue-green part of the spectrum. The reason is that the assumption of zero water-leaving radiance at 755 and 865nm fails due to backscattering by suspended mineral particles. Therefore, the near infrared channels 765 and 865nm used fur deriving the aerosol information are no longer valid for turbid coastal waters. The path-extraction is identified as a simple and efficient method of extracting the path radiance largely introduced due to light interaction through the complex atmosphere carried several aerosol and gaseous components and at the air-sea interface.interface.

• Journal of the Optical Society of Korea
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• 제15권1호
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• pp.90-95
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• 2011

12-year LIDAR observations of tropospheric aerosol vertical distribution using a Mie scattering LIDAR in Hefei ($31.9^{\circ}N$, $117.2^{\circ}E$) from 1998 to 2009 are presented and analyzed in this paper. Characters of temporal variation and vertical distribution of tropospheric aerosol over Hefei are summarized from the LIDAR measurements. The impacts of natural source and human activities on the aerosol vertical distribution over Hefei could be seen clearly. Dust particles from the north in spring could affect the aerosol distributions below about 12 km over Hefei, and aerosol scale height in April reaches $2.29{\pm}0.68\;km$. Both LIDAR measurements and surface visibility imply that aerosols in the lower troposphere have been increasing since about 2005.

• 환경영향평가
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• 제13권4호
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• pp.197-211
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• 2004

Visibility impairment was known as an indicator of the increased air pollution. In many previous studies, it is known that both directly emitted fine particles mainly from vehicles and secondary aerosols from photochemical reactions could contribute to this visibility impairment in addition to the meteorological condition. Furthermore, the visibility showed different change patterns according to the geographical condition. In order to research into the influence of these factors on visibility, this study analyzed the visibility at 15:00, observed from 1990 to 2001 in Seoul, Ganghwa, Susan, Gwangju, Jeju. As a result, the visibility was increased in Seoul except the rainfall period, but in Susan, Gwangju, Jeju, it decreased with the relative humidity (RH). Especially, in Seoul, the number of low visibility days was larger than other sites and variations of the visibility were sensitive to the concentration of air pollutants, such as TSP, $NO_2$, $O_3$. The visibility impairment was mainly observed in meteorological condition of RH<50% and relatively stationary front. Therefore it is inferred that photochemical smog could lead to the low visibility in Seoul. On the other hands, in Ganghwa and Susan, when RH was 60~70%, the low visibility observed under the influence of the transports of air pollutants from nearby cities as well as humid air mass from coastal region. And in Jeju, sea fog and humid air mass caused the visibility impairment when the RH was larger than 80%. Finally, during the observational period, some cases of low visibility phenomena were simultaneously observed in the vast region including Seoul, Susan, Ganghwa. It not only includes the visibility aggravation by Asian Dust, but also could be caused by the movement and diffusion of flying dust or secondary aerosols. Moreover, the result shows that these phenomena could be mainly influenced by meteorological factors covering the wide regions.

• 한국지구과학회지
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• 제43권1호
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• pp.77-90
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• 2022

최근 동아시아 지역에서 인위적 배출량의 감소에도 불구하고, 봄철에 한국에서는 잦은 연무 사례가 발생하고 있다. 북동 태평양에서 자주 발생하는 대기 블로킹은 지구 규모 대기 변동과 동아시아 지역의 서풍 기류를 정체시키기도 한다. 2019년 3월 동아시아 지역의 온난하고 정체적인 종관 기상 특성이 알래스카 대기 블로킹이 발생한 6-7일 후에 일어나고 있었다. 특히, 2019년 3월 18-24일에 발생한 알래스카 대기 블로킹은 3월 25-28일 동안 한국에서 일평균 미세먼지(particulate matter; PM₁₀) 질량농도가 50 ㎍ m^-3을 넘는 고농도 PM₁₀ 연무 사례가 발생하는 데 영향을 미치고 있었다. 한편, WRF-Chem 모델을 활용하여 한국의 고농도 PM₁₀ 연무 사례에 대한 인위적 배출의 장거리 수송 기여도는 30-40%를 나타내고 있었다. PM₁₀ 에어로졸 구성 성분인 황산염, 질산염, 암모늄, 블랙 카본, 유기 탄소, 기타 무기물의 장거리 수송 기여도는 각각 10-15, 20-25, 5-10, 5-10, 5-10, 15-20%를 나타내었다. 질소 산화물이 온난하고 정체적인 대기에서 암모늄과의 광화학 반응으로 형성된 질산암모늄은 한국의 고농도 PM₁₀ 연무 사례에 대한 장거리 수송 기여도가 PM₁₀ 에어로졸 중 가장 큰 비중을 나타내고 있었다.

• 한국대기환경학회지
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• 제9권1호
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• pp.1-10
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• 1993

A brief description on the greenhouse gases, the greenhoue effect, sea level changes, forcing of climate, the history of Earth's changing climate based on the IPCC REPORT and the records of the recent variation of the climate in the Republic of Kore is presented here for help enhancing awareness of the issues. The climate of the Earth has the potential to be changed on all timescales by the fluctuations of the concentrations of radioactively active greenhouse gases, solar radiation, aerosols and albedo. However, the rate of the recent global warming seems to be larger and rapid than any have occurred thorughout recorded history enough to draw the world-wide attention and worry concerned with the theme of environment and development. There are still uncertainties in the predictions relating to the timing, magnitude and the pattern of the climatic change due to the current incomplete understanding of various aspects of the complex processes. Nonetheless, the scientific results avaliable is sufficient to allow for decisive precautionary measures to be taken.