• Journal of Korean Society for Atmospheric Environment
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• v.25 no.6
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• pp.550-561
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• 2009

This study is to investigate the air pollution characteristics of an industrialized midsize west-coastal city by comparing air quality to a neighboring inland city. The hourly averaged data of $O_3$, $SO_2$, $NO_2$, CO, and $PM_{10}$ measured from continuous air quality monitoring sites in Gunsan (coastal) and Jeonju (inland) were analyzed. The data set covers the period from 2004 to 2006. The annual average concentrations of the air pollutants in two cities were compared in their abundances and temporal trends as well. $O_3$ and $SO_2$ in Gunsan were relatively higher than those in Jeonju, while vice versa in case of $NO_2$ and $PM_{10}$. It seems that heavy automobile emissions from Jeonju mainly bring on higher $NO_2$ and $PM_{10}$ than those in Gunsan on annual base. $NO_2$ concentrations in both cities showed bimodal diurnal variations with peaks in the morning and in the late evening. These peaks correspond to the coupled effects of rush hour traffic and meteorological conditions (i.e., variation of mixing height and dispersion conditions). Maximum hourly averages of $NO_2$ ranged from 18 ppb to 28 ppb at Jeonju, and from 12 ppb to 20 ppb at Gunsan. $O_3$ showed typical diurnal variation with a maximum in the afternoon between 14:00 and 16:00 LST. Diurnal variations of CO and $PM_{10}$ were similar to $NO_2$ while $SO_2$ was similar to $O_3$. Seasonal variations of $PM_{10}$ in both cities indicated that their concentrations during spring season were significantly high. Asian dust storms occur frequently during spring and seem to affect increase in $PM_{10}$. High $O_3$ and $PM_{10}$ days were selected from both cities. The analyses based on the HYSPLIT trajectory model during the high $O_3$ and $PM_{10}$ showed these episodes (six cases) were mostly coincident with Asian dust storm originated from northern China and Mongolia. However, these high air pollution episodes in the west coastal cities may not only be caused by the Asian dust but also affected by other air pollutants transported from China accompanying the Asian dust.

• Journal of Astronomy and Space Sciences
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• v.25 no.4
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• pp.425-434
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• 2008

The mean temperature equation is a key factor in calculating GPS meteorological information. A local mean temperature equation should be used to improve accuracy of GPS PWV (Precipitable Water Vapor). In this paper, four local mean temperature equations, HP, $HP_M,\;HPt_Y,\;and\;HPt_M$ from Ha & Park (2008) were used to analyze the effects of local models in determining GPS PWV. Four different sets of GPS PWVs were compared with radiosonde PWV to validate the accuracies of local models. GPS PWVs of four local models have similar trends compared against radiosonde PWV. The bias and RMS error were the same level: the bias is ${\sim}3mm$ and the RMS is ${\sim}3.6mm$ after the bias was removed. Especially, with $HPt_Y\;and\;HPt_M$ models one can obtain accurate PWVs even without surface temperature measurements. And we investigated dry bias of radiosonde measurements depending on sensor types and observation time at Sokcho weather station. After the radiosonde sensor equipment was changed from RS80-15L to GRS DFM-06, dry bias of radiosonde PWV decreased about 18.2% during daytime (KST 09:00), and 16.1% during nighttime (KST 21:00).

• Journal of Korean Society of Environmental Engineers
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• v.31 no.5
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• pp.358-363
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• 2009

The HSPF (Hydrological Simulation Program-Fortran) model was applied to the Kyoungan stream watershed to analyze effects of watershed management plans on receiving water qualities. Utilizing BASINS 3.1 GIS program, the Kyoungan stream watershed was divided into 57 sub-basins and model input parameters were obtained, from DEM (Digital Elevation Model), land use type, stream map, and wastewater treatment facilities, etc.. The hydrologic module of the model was validated based on the measured meteorological data and stream flow data. Then the model was calibrated and verified against the field measurements of water qualities, including temperature, DO, BOD, $NO_3-N$, $NH_3-N$, Org-N, TN and TP. In most cases, there were reasonable agreements between measurements and predictions. The validated model was used to analyze the water quality improvements in the main stream of Kyoungan stream according to the watershed management plans in sub-basins, which are three different scenarios: water quality improvement in tributaries through watershed management activities, expansion and up-grade of wastewater treatment plants, and application of first and second scenarios together. It was concluded that expansion and upgrade of wastewater treatment plants would be more effective than watershed management activities. In order to improve water qualities to the satisfactory level, both watershed management and point source control must be required in the Kyoungan stream.

• Journal of Radiation Protection and Research
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• v.25 no.2
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• pp.75-80
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• 2000

The predicted results of INDAC code were compared with measured $^3H$ concentrations in air and pine-needle around the Wolsung site. The optimal sets of input data to INDAC were in addition selected by comparing the measured values with the predicted values of INDAC based on various conditions such as the release modes of effluents into the environment, the classification of wind classes, and the consideration of terrain. The predicted $^3H$ concentrations in air and pine-needle were shown to have good agreement with measured values, although there are some limitations such as uncertainties in measured values, complex topology around the site, and the land-sea breeze effects. The assumption on the $^3H$ behavior in vegetables or plants that the ratio of $^3H$ concentration in plant water to $^3H$ concentration in atmospheric water is 1/2 was shown to be conservative in terms of the audit calculation performed by the regulator. It was also found that data sets based on mixed mode and no terrain data were not appropriate for the audit calculation ensuring the compliance with regulations. Thus, if the mixed mode is considered as the release mode of effluents into the environment, meteorological data measured at 58 m height and terrain data should be used to evaluate the atmospheric dispersion factor.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.70-78
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• 1991

Both long period of summer drought and unusual high water temperature in 1988 caused the harmfull effect to the aquacultural organisms in south coast of Korea. One of those was the mass mortality of arkshell seedlings in Jinhae Bay. The purpose of this study was to verify the effects of environmental factors on arkshell seedlings by investigating not only water quality and food organisms in culturing grounds, but also meteorological conditions. Water temperature in November was higher at $2.0^{\circ}C$ than mean water temperature and the concentration of total inorganic nitrogen and N/P ratio were $0.38{\mu}g-at/l,$ 0.98, respectively which indicated the exhaustion of nutrients, especially nitrogen in the study area. In analysis of phytoplankton population structure, species diversity index(H) , equitability-index(e), species richness $index(d_1)$ were low, but dominance $index({\delta}_2)$ was high at the value of 98.4 and dominant species was Nitzschia pungens. In conclusion, it seems that mass .mortality of arkshell seedlings in November was resulted from the metabolism disorder with poor food organism under the unstable marine environment.

• Journal of Wetlands Research
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• v.22 no.2
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• pp.106-112
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• 2020

Wetlands play an important function and role in hydrological, environmental, and ecological, aspects of the watershed. Water level in wetlands is essential for various analysis such as for the determination of wetland function and its effects on the environment. Since several wetlands are ungauged, research on wetland water level prediction are uncommon. Therefore, this study developed a water level prediction model using multiple regression analysis, principal component regression analysis, artificial neural network, and DNN to predict wetland water level. Geumjeong-Mountain Wetland located in Yangsan-city, Gyeongsangnam-do province was selected as the target area, and the water level measurement data from April 2017 to July 2018 was used as the dependent variable. On the other hand, hydrological and meteorological data were used as independent variables in the study. As a result of evaluating the predictive power, the water level prediction model using DNN was selected as the final model as it showed an RMSE value of 6.359 and an NRMSE value of 18.91%. This research study is believed to be useful especially as a basic data for the development of wetland maintenance and management techniques using the water level of the existing unmeasured points.

• Fire Science and Engineering
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• v.28 no.6
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• pp.13-21
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• 2014

Forest fire has a number of variables and since the effects of wind fields are bigger than any other variables, it is essential to know wind direction and velocity for the forest fire extinguishing techniques and the prediction of fire spread. With regards to the local area that has a high chance of forest fire, the data from meteorological observatory in the area is used for the estimation of wind velocity. It is relatively easy to obtain automatic weather station (AWS) data which are available for the whole nation. There is a chance that the data from the weather station may be different with the actual data at the mountain areas. In this study simply shaped hills (Sae-byeol hill of Jeju Island and port Ma-geum in An-myeon Island in the sea side) were selected as the experimental locations to minimize the distortion of the wind field by the adjacent geographic features. Spot measurements and analysis of computational fluid dynamics (CFD) for the given geographic features were conducted to examine and compare their consistency. As a conclusion It is possible to predict wind patterns in these simple locations.

• Journal of Korean Society on Water Environment
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• v.30 no.5
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• pp.539-548
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• 2014

This study was carried out to investigate algal community structures and their correlations with environmental factors on five weir areas in the Nakdong River, South Korea. Water qualities, hydrodynamics, meteorological conditions and algal species compositions were observed in studied sites from May 2010 to Dec. 2013. Results showed that average total phosphorus concentration of 2013 was decreased by 52.4% in comparing with that from 2010 to 2011. Chlorophyll.a concentrations were positive significant with water temperature, pH, total phosphorus and total nitrogen, but is not significant with turbidity and suspended solids. Seasonal successions of algae were observed that Stephanodiscus sp. was dominant species with 65.3% of dominant frequency in studied site. Large algal biomass of the low temperature-adapted diatoms were observed during temperature range of $4{\sim}9^{\circ}C$, but large cyanobacterial biomass mainly during high temperature period ranged from $22^{\circ}C$ to $32^{\circ}C$. Microcystis sp. dominated during high water temperature in summer. The yearly correlations of algal biomass with accumulated solar radiations were not significant but seasonal correlations of summer from June to August were significant with correlation coefficient 0.33 (p<0.05). There were not significant correlations between turbidities and algal biomass. Turbidity and suspended solids concentrations were not significant correlation with algal biomass. According to the results, algal communities had strong correlation with water temperature and had partially correlation with solar radiation. For an effective management of algal blooms, water managers should survey with more long-term monitoring of various environmental factors and algal communities.

• Journal of Biosystems Engineering
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• v.3 no.2
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• pp.100-113
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• 1978

Drying grain with conventional artificial drying methods requires great quantities of petroleum fuels. Depletion of fossil fuel increases the need of the utilization of solar energy as an alternative to petroluem fuels for drying grain , an energy intensive agricultural operation. Many techniques for the utilization of solar energy in grain drying have been developed, however, there are many problems in adopting solar energy as an energy sources for drying grain. Futhermore, very little research has been done on solar grain drying in Korea. This study was conducted to evaluate the availability of solar energy for drying of rough rice in Chuncheon, Suweon, and Jinju areas based on 50year meteorological data, and to analyze experimentally the performance of a solar air collector for dying grain, and to find the effects of solar heated air compared to unheated air on the rate of drying and energy consumption required for drying of rough rice. The results of this study was may be summarized as follows ; 1. Monthly average daily total radiation on a horizontal surface in October was 260.6 ly/day for Chuncheon, 240.3 ly/day for Suweon , and 253.4 ly/day for Jinju area, respectively. 2. the ratio of monthly average daily diffuse radiation to daily total radiation on a horizontal surface was approximately 0.41 for Chuncheon, 0.45 for Suweon, and 0.44 for Jinju area, respectively. 3. Although the statistical distribution curves of daily total radiation for the three locations were not identical , the differences among them were not large and may be neglected for many practical purposes. 4. I was estimated that the optimum tilting angle of the collector in October was approximately 46 degrees for Chuncheon and Suweon and 45 degrees for Jinju. 5. The ratio of the total radiation on a optimum tilting plane to that on a horizontal plane was estimated to be 1.36 for Chuncheon, 1.31 for Suweon, and 1.27 for Jinju , respectively. 6. The collection efficiency of the solar air collector ranged from 47. 8 to 51. 5 percent at the air flow rates of 251. 1-372.96 $m^3$/hr. High efficiency remained nearly , constant during the best sunshine hours, 10 a.m. to 2 p.m. and decreased during other hours. More energy was collected as the air flow rate incresed. 7. The average temperature rise in the drying air from the solar collector for the test period varied from $6.5^\circC$ to $21.8^\circC$ above the ambient air temperature. 8. Solar-dried rough rice averaged 13.7 percent moisture (w.b.) after 130 hours of drying with the air flow rate of 1. 64 ccm/$m^3$, and rough rice dried with natural air averaged 15.1 percent moisture (w.b.) after 325 hours of drying with the same air flow rate. 9. Energy saving of 2.4 kwh per $m^3$ percentage point of moisture removed was obtained from solar heated air drYing. The solar bin used 53.3 percent less energy per percentage point of moisture removed than the natural air bin.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.3
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• pp.148-152
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• 1989

This field experiment was carried out to determine the effects of fertilizer application time in early spring on growth, dry matter (DM) yield, crude protein (CP) content, crude protein yield (CPY), N recovery, acid detergent fibej (ADF) content and DM digestibility (DMD) of grasses for hay. Application times of fertilizer were March 10, 20, 30, April 9. 19, and control (non-fertilized) plot was involved. The fust harvesting data for hay was May 9 (early heading stage) and the regrowth yields were investigated for soiling, 1989. In all fertilized plots, the growth, DM yield, CP, CPY and N recovery of grasses were significantly increased compared with control, and the best grass growth, DM yield, CP, CPY, N recovery and DMD were observed on March 20 and 30 among all fertilized plots. On March 20 and 30 in this experiment, the accumulated temperature was 200 and 280^{\circ}C.$, and the subsoil temperature at 10 cm depth was 8 and 10^{\circ}C.$. Considering the average meteorological condition in Suwon area, the optimum application time of early spring for hay may be recommended from April 10 to 15. i\ulcornerfW3U% (L. westock Experiment Station, RDA. Suwon 440 - 350. Korea)