• Journal of Korean Society for Atmospheric Environment
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• v.6 no.1
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• pp.11-21
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• 1990

To quantitatively estimate the effect of yellow sand(loess) fromt he Northern China, various soil sources having similar chemical compositions to yellow sands should be separated and identified. After that, mass contribution for yellow sand can be calculated. The study showed that it was impossible to solve this problem by the traditional bulk analyses. However, particle-by-particle analysis by a CCSEM (computer controlled scanning electron microscope) gave enormous potentials to solve it. To perform this study, seven soil source data analyzed by CCSEM were obtained from Texas, U.S.A. Initially, each soil date was classified into two groups, coarse and fine particle groups since the particle number distribution showed a minimum occurring at 5.2$\mu$m of aerodynamic diameter. Particles in each group were then classified into one of the 283 homogeneous particle classes by the universal classification rule which had been built by an expert system in the early study. Further, mass fractions and their uncertainties for each class in each source were calculated by the Jackknife method, and then source profile matrix for the 7 soil sources was created. To use the profile matrix in the study of source contribution, it is necessary to test the degree of collinearity among sources. The profiles were tested by the singular value decomposition method. As a result, each soil source characterized by artificially created variables was totally independent each other and is ready to use in source contribution studies as a receptor model.

• Journal of Environmental Science International
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• v.13 no.10
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• pp.891-902
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• 2004

In order to predict air pollution and Yellow-sand dispersion precisely, it is necessary to clarify the sensitivity of meteorological field input interval. Therefore numerical experiment by atmospheric dynamic model(RAMS) and atmospheric dispersion model(PDAS) was performed for evaluating the effect of temporal and spatial resolution of meteorological data on particle dispersion. The results are as follows: 1) Base on the result of RAMS simulation, surface wind direction and speed can either synchronize upper wind or not. If surface wind and upper wind do not synchronize, precise prediction of Yellow-sand dispersion is strongly associated with upwelling process of sand of particle. 2) There is no significant discrepance in distribution of particle under usage of difference temporal resolution of meteorological information at early time of simulation, but the difference of distribution of particles become large as time goes by. 3) There is little difference between calculated particles distributions in dispersion experiments with high temporal resolution of meteorological data. On the other hand, low resolution of meteorological data occur the quantitative difference of particle density and there is strong tendency to the quantitative difference.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.920-922
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• 2003

Large plumes of yellow send or yellow dust blow out over the Sea of Japan and the Japanese archipelago from mainland of China. In this study, the methodology to capture the perspective on the large Yellow dust storm by using MODIS data is discussed. As the typical image of yellow send, MODIS data obtained of April 8, 2002 were used in this study.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.134-135
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• 2000

에어로졸은 인위적으로 발생하거나 자연적으로 발생하는 먼지(토양 발생인 먼지, 생물학적 비해염입자, 유기입자 둥)로 나뉘어지는 데 자연적으로 발생하는 먼지의 대표적인 사례로 황사를 들 수 있다. 이는 시정악화나 해수성분의 변화, 강수의 pH 변화 등 여러 가지 방면에서 영향을 주고 있는 것으로 나타나고 있다(Parungo et al., 1995). 동북아시아 지역의 지역적인 특수성으로 인해 미네랄 에어로졸 표면에서의 화학반응 활성화가 황산염이나 질산염의 생성을 유발한다는 여러 가지 보고가 있다. (중략)

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.898-906
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• 2018

To investigate the effect of yellow dust on phytoplankton, a field survey and physiological experiments were carried out in the waters near Taean Peninsula from April 22 to 26, 2006, when yellow dust occurred. Phytoplankton populations during the yellow dust period were in the range of $26{\sim}290{\times}10^3cells{\cdot}L^{-1}$, a somewhat low standing crop. An increase in diatoms (a main taxonomic group), especially benthic diatoms such as Paralia sulcate, a typical species for active mixed sea water areas, was also remarkable. In addition, the Chl-a concentration after yellow dust exceeded the Chl-a concentration change range according to the tide before yellow dust. As the concentration of yellow sand increased in a yellow sand treatment experiment, primary productivity decreased, and the maximum assimilation number showed the same tendency. In the 48h culture experiment, primary productivity of the test group was lower than that of the control group at the early stage (T0) of yellow sand treatment, but after 48 hours (T48), the test group showed higher primary productivity than the control group. In particular, the primary productivity of the test group significantly increased to 321 % after 48 hours. Therefore, strong physical environment accompanied by yellow dust may temporarily inhibit the growth of phytoplankton in the waters adjacent to China in the early stage of yellow dust, but the formation of stable water mass has also been identified as a potential factor promoting the growth of phytoplankton.

• 한국해양학회지
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• v.27 no.1
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• pp.66-77
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• 1992

Tidal sand ridges and sand waves are well developed in the Yellow Sea off Tae-An Peninsula, Korea. Their transport directions were inferred based on high resolution seismic profiles, surficial sediment characteristics and tidal regime. Tidal sand ridges are asymmetric, with long axes parallel to or slightly oblique to the dominant NE-SW tidal current direction. They show steep south and/or southeast flanks, which are in concordance with the apparent direction of internal cross-bedding in the south. Holocene sediments occur in accordance with distributional patterns of tidal sand ridges. These features indicate that Holocene active tidal sand ridges move toward the open sea in southeast, south and southwest direction. Sand waves which are distributed in flat sea floor with depth of about 40-60m show also asymmetric forms with a steep east-to-northeast face. Surficial sediments in the sand wave field are characterized by well sorted fine sands compared with poorly sorted adjacent areas. The sand waves appear to undergo easterly or northeasterly landward movement.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.281-282
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• 2003

The significant spring-time phenomenon known as the "Yellow Sand" influences not only regional but also global climate. It′s believed that frequency of yellow-sand events has increased in recent years. To investigate the possible factors inducing these special strong weather phenomenon and its impacts on meteorological elements, intensive sampling will be conducted by ADEMRC/KJIST from March to May 2003. Lagrangian trajectory (forward and backward), cluster analysis, factor analysis and satellite remote sense (SRS) techniques will be employed to inspect the mechanisms of yellow-sand. (omitted)

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.215-224
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• 2004

We report the high concentration episodes for PM$_{10}$, SO$_2$, NO$_2$, and $O_3$ in many urban areas Korea during 2002. The high concentration episodes are identified based on the National Ambient Air Quality Standards and the observations obtained from the Regional Air Monitoring Network composed of approximately 160 air pollution monitoring stations located in a number of major or big cities in South Korea including Seoul, Pusan, Daegu, and Incheon cities. The results show that the twenty cases of high concentration episodes in 2002 consists of both ozone warning episodes (6 cases) and high PM$_{10}$ concentration cases (14 cases), and one half of the latter are found to occur in association with the Yellow Sand (Asian Dust) phenomena. The most outstanding characteristics of the reported episodes are the excessively high levels of maximum PM$_{10}$ concentrations during the Yellow Sand period (i.e., exceeding 3,000$\mu\textrm{g}$/㎥ in April, 2002) and their variable occurrence frequencies across seasons. The high ozone concentration episode days are mainly resulting from both the high photochemical reactions and poor ventilations. The high PM$_{10}$ concentration days during non Yellow Sand periods, however, mostly occurred under the influence of synoptic meteorological conditions such as stagnant or slowly passing high pressure centers, and consequently prevailing weak wind speeds over the Korean peninsula. The overall results of our study thus suggest the importance of both synoptic and local meteorological factors for high concentration levels in the major and/or big cities in Korea.n Korea.

• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.2
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• pp.1-15
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• 2002

Atmospheric aerosols interact with sunlight and affect the global radiation balance that can cause climate change through direct and indirect radiative forcing. Because of the spatial and temporal uncertainty of aerosols in atmosphere, aerosol characteristics are not considered through GCMs (General Circulation Model). Therefor it is important physical and optical characteristics should be evaluated to assess climate change and radiative effect by atmospheric aerosols. In this study GMS-5 satellite data and surface measurement data were analyzed using a radiative transfer model for the Yellow Sand event of April 7~8, 2000 in order to investigate the atmospheric radiative effects of Yellow Sand aerosols, MODTRAN3 simulation results enable to inform the relation between satellite channel albedo and aerosol optical thickness(AOT). From this relation AOT was retreived from GMS-5 visible channel. The variance observations of satellite images enable remote sensing of the Yellow Sand particles. Back trajectory analysis was performed to track the air mass from the Gobi desert passing through Korean peninsular with high AOT value measured by ground based measurement. The comparison GMS-5 AOT to ground measured RSR aerosol optical depth(AOD) show that for Yellow Sand aerosols, the albedo measured over ocean surfaces can be used to obtain the aerosol optical thickness using appropriate aerosol model within an error of about 10%. In addition, LIDAR network measurements and backward trajectory model showed characteristics and appearance of Yellow Sand during Yellow Sand events. These data will be good supporting for monitoring of Yellow Sand aerosols.

• Journal of Environmental Health Sciences
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• v.29 no.3
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• pp.91-96
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• 2003

This study was intended as an investigation of characteristics of background site atmospheric respirable particulate matters(RPM), and fine particles(<2.5 ${\mu}{\textrm}{m}$). The particle size distributions during the phenomenon of Yellow Sand(YS) occurs from April, 2001. Atmospheric aerosol particulate matter was directly collected on the Jeju island between 1 to 30, April, 2001 using an eight-stage cascade impacter(particle size range: 0.43-11 ${\mu}{\textrm}{m}$), and cyclone separator(cut size: 2.5, 10 ${\mu}{\textrm}{m}$). The episode of YS observed in background monitoring site, Kosan and appeared 2 times at sampling period. The mass concentrations of fine and coarse particles for YS episode were 34.2 and 59.6 $\mu\textrm{g}$/㎥, respectively, which were significantly increased amounts compared to 13.3 and 13.0 $\mu\textrm{g}$/㎥ for NonYS(NYS). Most size distributions had two peaks, one at 0.43∼.65 ${\mu}{\textrm}{m}$ and the other at 3.3${\mu}{\textrm}{m}$4.7 ${\mu}{\textrm}{m}$. The result of analysis of water-soluble ion component indicated that sulfate was mainly ion component, but nitrate and calcium ion was significantly increased at the YS episode.