• 한국대기환경학회지
• /
• 제29권5호
• /
• pp.682-691
• /
• 2013

The aerosol extinction vertical profile and surface visibility have been derived from the Microtops-II sunphotometer observation during the winter 2011 intensive observation period (IOP) at Seoul, Korea. Using models of degradation of aerosol optical thickness (AOT) and aerosol scale height, we have performed extinction-visibility modulation to determine the height dependent aerosol extinction and visibility. It is shown that the aerosol loading is relatively low during IOP (mean $AOT_{550}=0.22{\pm}0.08$, ${\AA}$ngstr$\ddot{o}$m exponent=$1.14{\pm}0.26$). Modeled extinction by use of Microtops II sunphotometer data shows good agreement with measurements by the Multi-wavelenth Polarization Lidar (MPoLAR), and the derived surface visibility are consistent with data from the transmissometer. These results emphasize the use of a vertically resolved extinction from AOT to predict visibility conditions at ground level.

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

• 한국지리정보학회지
• /
• 제16권2호
• /
• pp.141-151
• /
• 2013

본 연구에서는 MODIS 인공위성으로 분석된 에어러솔 광학두께 자료와 지상에서 관측된 시정거리 자료를 이용하여 에어러솔 연직분포 모델링을 수행하였다. 위성과 지상관측자료로부터 에어러솔의 척도 고도를 구할 수 있었으며, 그 결과는 복사전달 모델에서 사용되고 있는 표준대기 모델과 비교에서 만족할 만한 수준의 근사치를 보였다. 그리고 실제 사례로서 대기가 청명한 경우(${\tau}_{MODIS}=0.12{\pm}0.07$, 시정거리=$21.13{\pm}3.31km$)와 혼탁한 경우(${\tau}_{MODIS}=1.71{\pm}0.85$, 시정거리 =$13.33{\pm}5.66km$)에 대해서 적용하여 척도 고도를 산정한 결과는 각각 전국 평균값으로서 $0.63{\pm}0.33km$와 $1.71{\pm}0.84km$로 나타났다. 그리고 이 결과를 바탕으로 대기 에어러솔 소산계수의 연직분포를 구할 수 있었으며, 최종적으로 KML 형식으로 코딩되어 관심 영역의 대기 환경 특성 변화를 감시하는데 도움이 될 것으로 기대된다.

• 대기
• /
• 제27권2호
• /
• pp.225-233
• /
• 2017

Korea has recently suffered from severe hazes, largely being long-range transported from China but frequently mixed with domestic pollution. It is important to identify the origin of the frequently-occurring hazes, which is however hard to clearly determine in a quantitative term. In this regard, we suggest a possible classification procedure of various hazes into long-range transported haze (LH), Yellow Sand (YS), and urban haze (UH), based on mass loading of fine particles, time lag of PM mass concentrations between two sites aligned with dominant wind direction, backward trajectory of air mass, and the mass ratio of PM2.5 to PM10. The analysis sites are Seoul (SL) and Baengnyeongdo (BN), which are distant about 200 km from each other in the west to east direction. Aerosol concentrations at BN are overall lower than those of SL, indicative of BN being a background site for SL. We found distinct time lag of PM2.5 and PM10 concentrations between BN and SL in case of both LH and YS, but the intensity of YS being stronger than LH. Time scale (e-folding time scale) of LH appears to be longer and more variable than YS, which implies that LH covers much larger spatial scale. In addition, we found linear and significant correlations between ${\tau}_a$ obtained from sunphotometer and ${\tau}_{cal}$ calculated from surface aerosol scattering coefficient for LH episodes, relative to few correlation between those for YS, which might be associated with transported height of YS being much higher than LH. Therefore surface PM concentrations for the YS period are thought to be not representative for vertical integrated amount of aerosol loadings, probably by virtue of decoupled structure of aerosol vertical distribution. Improvement of various hazes classification based on the current result would provide the public as well as researchers with more accurate information of LH, UH, and YS, in terms of temporal scale, size, vertical distribution of aerosols, etc.

• 대기
• /
• 제26권2호
• /
• pp.243-256
• /
• 2016

Total number concentration of aerosols larger than 10 nm ($N_{CN10}$), 3 nm ($N_{CN3}$), and cloud condensation nuclei ($N_{CCN}$) were measured during four different ship cruises over the Yellow Sea. Average values of $N_{CN10}$ and $N_{CCN}$ at 0.6% supersaturation were 6914 and $3353cm^{-3}$, respectively, and the minimum value of $N_{CN10}$ was $2000cm^{-3}$, suggesting significant anthropogenic influence even at relatively clean marine environment. Although $N_{CN10}$ and $N_{CN3}$ increased near the coast due to anthropogenic influence, $N_{CCN}$ was relatively constant and therefore $N_{CCN}/N_{CN10}$ ratio tended to decrease, suggesting that coastal aerosols were relatively less hygroscopic. In general $N_{CN10}$, $N_{CN3}$, and $N_{CCN}$ during the cruises seemed to be significantly influenced by wet scavenging effects (e.g. fog) and boundary layer height variation. Only one new particle formation (NPF) event was observed during the measurement period. Interestingly, the NPF event occurred during a dust storm event and spatial scale of the NPF event was estimated to be larger than 100 km. These results demonstrate that aerosol and CCN concentration over the Yellow Sea can vary due to various different factors.

• 대한원격탐사학회지
• /
• 제26권6호
• /
• pp.617-627
• /
• 2010

Although many researches for heat island study have been developed, there is little attempt to link the findings to actual and hypothetical scenarios of urban developments which would help to mitigate the Urban Heat Island (UHI) in cities. The aim of this paper is to analyze the UHI at urban area with different geometries, land use, and environmental factors, and emphasis on the influence of different geometric and environmental parameters on ambient air temperature. In order to evaluate these effects, the parameters of (i) Air pollution (i.e. Aerosol Optical Thickness (AOT)), (ii) Green space Normalized Difference Vegetation Index (NDVI), (iii) Anthropogenic heat (AH) (iv) Building density (BD), (v) Building height (BH), and (vi) Air temperature (Ta) were mapped. The optimum operational scales between Heat Island Intensity (HII) and above parameters were evaluated by testing the strength of the correlations for every resolution. The best compromised scale for all parameters is 275m resolution. Thus, the measurements of these parameters contributing to heat island formation over the study areas of Hong Kong were established from mathematical relationships between them and in combination at 275m resolution. The mathematical models were then tabulated to show the impact of different percentages of parameters on HII. These tables are useful to predict the probable climatic implications of future planning decisions.

• 한국환경과학회지
• /
• 제21권7호
• /
• pp.855-863
• /
• 2012

This study analyzed mass concentrations of TSP, PM10 and PM2.5 and elemental constituents according to the isentropic backward trajectories of air parcel from Cheongwonin East Asia during the period January - October, 2011. Mass concentrations of the continental polluted airflow (CP) showed levels of TSP and PM10 mass concentrations higher than the continental background airflow (CB). Also, PM2.5 mass concentrations of anthropogenic fine particles ran higher in CP than in CB. The elemental constituents and elemental constituent ratio ended up varying depending on the origin of atmospheric aerosols generated. The average absolute content of elemental constituents reached its height in CB, the ratio of anthropogenically originating elements (PE) among the all elements (AE) analyzed marked a high in CP, and Mg+Na/AE reached its height in the oceanic airflow (OA). At the same time, TSP, PM10 and PM2.5 mass concentrations, the ratio of PM2.5/TSP and PE/AE element ratio ran higher in CP than CB. Episodes of large-scale transport of atmospheric pollutants as observed at Cheongwon were 8 cases and 22 days. The ratios of PM10, PM2.5 among TSP mass concentrations showed different results and the ratios of PM2.5 showed an increasing trend in the episodes of anthropogenic air pollution transport. Overall, dustfall episodes show a level of elemental constituents higher than those of anthropogenic air pollution.Dustfall episodes were observed to contain more of Fe, Al and Ca originating from continental soils and those of air pollution were observed to contain more of Zn, Mn, Cu and Pb. By difference in contents of absolute elemental constituents, episodes of anthropogenic air pollution showed a high PE/AE rate, and dustfall episodes a high SE/AE rate.