• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.4
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• pp.209-216
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• 1991

Characteristics of suspended sediment concentration of equilibrium and non-equilibrium state caused by waves and currents are investigated by conducting a movable bed experiments in wave tanks. In the region where a downward flux of suspended sediment is larger than a upward flux, time-averaged vertical distribution of suspended sediment does not indicate logarithmic distribution. A new numerical procedure for predicting time-averaged suspended sediment concentration is also proposed based on two-dimensional advective diffusion equation by applying a split-operator approach. It is found that the unposed procedure can predict measured distribution of suspended sediment satisfactorily.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.3
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• pp.222-229
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• 1993

Total suspended particles in the atmosphere were collected on the quartz fiber filters using an ANdersen Hi-volume air sampler from March 1989 to October 1989 and from June 1990 to February 1991, at Chung-Ang University in Seoul. A total amount of eight heavy metals (Cr, Zn, Cd, Pb, Fe, V, Ti, Mn) in total suspended particles were determined by ICP spectrophotometer. The annual arithmetic mean concentration of total suspended particle was 162.3$\mug/m^3$ and eight metals(Cr, Zn, Cd, Pb, Fe, V, Ti, Mn) were 11.6, 609.2, 3.5, 337.1, 2739.5, 15.1, 89.4 and 100.5ng/$m^3$, respectively. The concentration of total suspended particle was highest in the spring(343.7$\mug/m^3$) and lowest in the summer(91.8$\mug/m^3$). These heavy metals were distinguished into two groups in terms of their particle size distribution. The contents of first-group heavy metals (Fe, Ti, Mn) were increased in accordance with the growth of the particle size. The contents of the second-group ones such as Pb, Cd, V, and Zn, on the contrary, came to increase according as the particle size reduced. Statistical analysis indicated that there was a correlation between total suspended particle and Fe in coarse particles, and between total Suspended Particle and Zn, Pb in fine particle.

• Water for future
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• v.13 no.4
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• pp.33-40
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• 1980

It has been very difficult to analyse, clearly, the mechanism of the suspended sediment that changes, largely, the coastline, on-shore and off-shore. It is due to not only the complexity of the factors in nature but the measurement technique of suspended sediment characteristics both in nature and loboratory. The purpose of this paper are to obtain the time-rate of change in the concentration of suspended sediment, the vertical distribution of it and the effect of the fall velocity of its particle, and to make clear the mechanism of sand transportation in suspension, analysing the diffusion equation, by the computer, due to the small amplitude wave theory.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.3
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• pp.240-249
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• 1993

The suspended sediment mechanism was systematically investigated by analyzing existing data together with new data obtained under several wave folds. A simple empirical formula has been developed to predict the time-averaged suspended sediment concentration above movable bed by the effect of wave and current interaction. The present study shows linear dependency of the diffusion coefficient of suspended sediment on the eddy viscosity coefficient obtained by considering the ripple geometry. Furthermore, it is proved that reference sediment concentration is reduced by the effect of ripple asymmetry.

• Journal of Korean Society for Atmospheric Environment
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• v.8 no.4
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• pp.247-256
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• 1992

Airborne suspended particulates were collected at Shinchon by a high volume cascade impactor from Sep. 1990 to Aug. 1991. Organic matter was extracted from particulates and fractionated by liquid-liquid extraction and thin layer chromatography. Substances in the PAHs and nitroarenes'subfraction of neutral fraction were determined by capillary gas chromatography. Based on unit risk estimates by multi-stage model of benzo[a]pyrene and the results of exposure estimates, cancer risk was assessed. The annual average concentration of total suspended particulates was 201.77g/$m^3$. The percentage of fine particulates was 57.40. The concentration of total suspended particulates showed seasonal variations and was high in winter and spring. The average concentration of extractable organic matter was 8.12g/$m^3$. In all, 21 PAHs were identified and quantified. The annual concentration of fluoranthene was 2.38ng/$m^3$, and that was the highest value of all PAHs. A carcinogenic compound, benzo[a]pyrene, was at a concentration of 1.84ng/$m^3$. All the 10 nitroarenes were also identified and quantified. The major nitroarene in the Shinchon area was 2,7-dinitrofluorene. The annual concentration of 1-nitropyrene was 1.56ng/$m^3$. Concentrations of PAHs and nitroarenes were high in winter and low in summer. The life time excess risk estimates of benzo[a]pyrene was calculated as 0.96 persons/a million population in this experiment. In the rank of relative potenties, carcinogenic effects of the other PAHs were calculated as 0.004-0.108 persons/a million population.

• Korean Journal of Remote Sensing
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• v.27 no.6
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• pp.677-692
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• 2011

Suspended sediment is an important oceanic variable for monitoring changes in coastal environment related to physical and biogeochemical processes. In order to estimate suspended sediment concentration (SSC) from satellite data, we derived SSC coefficients by fitting satellite remote sensing reflectances to in-situ suspended sediment measurements. To collect in-situ suspended sediment, we conducted ship cruises at 16 different locations three times for the periods of Sep.-November 2009 and Jul. 2010 at the passing time of Landsat $ETM_+$. Satellite data and in-situ data measured by spectroradiometers were converted to remote sensing reflectances ($R_{rs}$). Statistical approaches proved that the exponential formula using a single band of $R_{rs}$(565) was the most appropriate equation for the estimation of SSC in this study. Satellite suspended sediment using the newly-derived coefficients showed a good agreement with insitu suspended sediment with an Root Mean Square (RMS) error of 1-3 g/$m^3$. Satellite-observed SSCs tended to be overestimated at shallow depths due to bottom reflection presumably. This implies that the satellite-based SSCs should be carefully understood at the shallow coastal regions. Nevertheless, the satellite-derived SSCs based on the derived SSC coefficients, for the most cases, reasonably coincided with the pattern of in-situ suspended sediment measurements in the study region.

• Journal of Environmental Impact Assessment
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• v.9 no.2
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• pp.127-142
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• 2000

This research was performed for analyzing the transport of suspended solids during the harbor construction. In behalf of the research, we have analyzes the characteristics of suspended solids movement in sand reclamation of breakwater according to age of tide and tidal period at the construction spot of Pusan new harbor. In the process of sand reclamation, soil was dumped by a dumping device which direct soil from the barge to the bottom of the sea. According to the results from this research, suspended solid concentration was very high in the range of 5m from the dumping point right after the dumping. However these suspended solids settled very quickly and the solids concentration was very beyond 10m from the dumping point. It is deduced that the movement of solids dumped from barge has the tendencies as following; 1) Most of the dumped solids precipitated quickly after the dumping 2) The rest of the suspended solids are diffused slowly toward the bottom of the water being figured smoothing curve 3) The diffusion movement of suspended solids tend to proceed toward the shore line in a parallel motion with tidal current at the sea-bottom That is to say, most of the suspended solids precipitated very quickly even though highly concentrated solids produced at the bottom of the solids which did not precipitated spread with the tidal current horizontally along the bottom of the sea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.4
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• pp.323-329
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• 2004

In situ particle size and volume concentration of suspended sediment was measured at the mouth of Seomjin River Estuary In February 2001, using an optical instrument, 'LISST-100'. Time variation of in situ particle size and concentration shows: (1) during ebb tide, Seomjin River supplies relatively fine-grained particles with less-fluctuated, compared to during flood tide, and well-behaved concentrations following the tidal cycle; and (2) during flood tide, relatively coarse-grained particles with highly variable in size distribution and concentration flow upstream from Kwangyang Bay. This explains a poor correlation $(r^{2}=0.10)$ between sediment concentration and beam attenuation coefficient during flood and a high degree of correlation $(r^{2}=0.80)$ during ebb tide. Relatively fine grained and well defined, monotonous size distribution may promote the correlation between concentration and beam attenuation coefficient due to optical homogeneity of particles during ebb tide. Abundance of large aggregates with time-varying size and shape distributions may be mainly responsible for variations in optical properties of the sediment during flood tide, and thus may confound the relationship between the two variables. The difference in particle sizes and shapes between flood and ebb tides can also be observed on SEM images.

• Journal of Korean Society of Forest Science
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• v.88 no.4
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• pp.477-484
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• 1999

This study was conducted to investigate the effect of forest road on the suspended sediment yield into a stream in the small forest watershed. The samples of suspended sediment yield were collected at surveying points A and B in mountains watersheds unaffected by forest road, and at surveying point C affected by forest road. When hourly change of suspended sediment concentration was investigated, it showed the highest increase along the forest road, and the peak of suspended sediment concentration due to the watershed characteristics of each surveying point occurred before or at the same time with, the peak of discharge. This may be due to the time lag in which stagnated unstable suspended sediment moved strongly upon rainfall. Although suspended sediment load varied depending upon rainfall factors and surveying period, suspended sediment load per unit watershed flowed out 4.1 times more at the point C than at the point A and B. The suspended sediment load on 18~19 September, 1998, strongly affected by rainfall factors, was 4.179g/sec/㏊ at the point C, and 0.343g/sec/㏊ and 0.147g/sec/㏊ at the point A and B, respectively. This load was 12 times higher at the point C than at the point A and 28 times higher than at the point B.

• Ocean Systems Engineering
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• v.2 no.4
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• pp.289-295
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• 2012

Assume fluid eddy viscosity in the vertical direction is parabolic. Sediment particles diffuse with the given fluid eddy viscosity. However, when the vertical diffusion coefficient profile is computed from the suspended sediment concentration profile, the coefficient shows lager values than the fluid mixing coefficient values. This trend was explained by using two sizes of sediment particles. When fine sediment particles like wash load are added in water column the sediment mixing coefficient looks much larger than the fluid mixing coefficient.