• Journal of Environmental Science International
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• v.5 no.6
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• pp.713-718
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• 1996

We identified two characteristic turbulent flow cases, weakening and strengthening, which appear at the downwind side. Observations were made two times, Dec. 2-3. 1995 and Feb. 13-14. 1996 at Pusan National University site located downwind side of Kumjeong mountain. Meteorological observation system, tethersonde, was adopted to present observation. In the case of the west wind which blows perpendicular to Sanghak mountain located westward from the site, the wind speed highly increased in exponential with height. Therefore, the low level wind speed was so weak just like Taylor(1988)'s review. While the wind speed was intensified at 200-400m layer when the northwest wind blows from the continental Siberian high. We suppose 기 is because of the strong vertical convergence of flow between the surface inversion layer and the upper one, and also the horizontal convergence along the saddle and valley between the two mountains, Kumjeong and Sanghak-because of Bernoulli's effect. The inversion layer existed at surface-l00m and 500-600m level and the strong wind existed at about 200-400m layer.

• Journal of the Korean Institute of Landscape Architecture
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• v.14 no.2
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• pp.7-16
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• 1986

This study was carried out to investigate the effects of such erosion control measures as sowing, planting and small earth structures on the soil and vegetation. In order to study the changes in soil and vegetation, 36 plots were surveyed from 1981 to 1982 in the large erosion control area which is restored last 20 years. The factors which were measured included vegetation coverage, tree growth, number of species, soil depth, soil consistancy, and Chemical properties of soil. The results were as follows; 1) Maximum coverage of the overstory and understory was attained 7 years after the initiation of erosion control. So the overstory need to be tended and pruned. 2) Diversity of species increased until age 6 after which it began to decrease. 3) In order of tree growth, black locust was the fastest, followed by siberian alder and pitch pine. The initial growth of black locust, though the best among the 3 tree stop., decreased rapidly year by year. At the same time, siberian alder and pitch pine grew well until 12 and 6 years after the initiation of erosion control respectively. 4) Fifty percent of the initially planted trees died within 8 yeard. The mortality of siberian alder occurred until the 20th year while the mortality of pitch pine stopped after 10 years. Thereafter 500 trees per hectare were maintained. 5) The soil depth in A and B horision increased by 2cm annually during 20 years. The soil consistency also decreased rapidly until 7th year. The physical soil properties of the rehabilitated areas were improved after the 14th year. 6) The soil pH tend to decrease from 5.3 during the first year to 5.1 during the twentieth year. 7) The organic matter and nitrogen content in the soil were increased by fertilization but after 20 years these nutrients are still deficient for normal tree growth. 8) The phosphorous content in the soil was high in the first year but the longer the period after the initiation of erosion control the lese the content of phosphorous. 9) The biomass of black locust was the highest and increased continuously. The biomass of siberian alder on the contrary decreased from the 15th year because the number of trees in this place was very low. The total biomass in the twentieth year after erosion control initiation was 105.7 ton per hectare.

• Journal of the Korean Geographical Society
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• v.49 no.5
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• pp.675-689
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• 2014

This study applied Ensemble Empirical Mode Decomposition(EEMD), a new methodology to define the timing of spring onset over the Republic of Korea and to examine its spatio-temporal change. Also this study identified the relationship between spring onet timing and some atmospheric variations, and figured out synoptic factors which affect the timing of spring onset. The averaged spring onset timing for the period of 1974-2011 was 11th, March in Republic of Korea. In general, the spring onset timing was later with higher latitude and altitude regions, and it was later in inland regions than in costal ones. The correlation analysis has been carried out to find out the factors which affect spring onset timing, and global annual mean temperature, Arctic Oscillation(AO), Siberian High had a significant correlation with spring onset timing. The multiple regression analysis was conducted with three indices which were related to spring onset timing, and the model explained 64.7%. As a result of multiple regression analysis, the effect of annual mean temperature was the greatest and that of AO was the second. To find out synoptic factors affecting spring onset timing, the synoptic analysis has been carried out. As a result the intensity of meridional circulation represented as the major factor affect spring onset timing.

• Atmosphere
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• v.31 no.1
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• pp.29-43
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• 2021

In this study, two-step statistical approach including Principal Component Analysis (PCA) and Multiple Linear Regression (MLR) was employed, and main meteorological factors explaining the high-PM2.5 episodes were identified in two regions: Seoul and Busan. We first performed PCA to isolate the Principal Component (PC) that is linear combination of the meteorological variables observed at two levels: surface and 850 hPa level. The employed variables at surface are: temperature (T2m), wind speed, sea level pressure, south-north and west-east wind component and those at 850 hPa upper level variables are: south-north (v850) and west-east (u850) wind component and vertical stability. Secondly we carried out MLR analysis and verified the relationships between PM2.5 daily mean concentration and meteorological PCs. Our two-step statistical approach revealed that in Seoul, dominant factors for influencing the high PM2.5 days are mainly composed of upper wind characteristics in winter including positive u850 and negative v850, indicating that continental (or Siberian) anticyclone had a strong influence. In Busan, however, the dominant factors in explanaining in high PM2.5 concentrations were associated with high T2m and negative u850 in summer. This is suggesting that marine anticyclone had a considerable effect on Busan's high PM2.5 with high temperature which is relevant to the vigorous photochemical secondary generation. Our results of both differences and similarities between two regions derived from only statistical approaches imply the high-PM2.5 episodes in Korea show their own unique characteristics and seasonality which are mostly explainable by two layer (surface and upper) mesoscale meteorological variables.

• Journal of Integrative Natural Science
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• v.17 no.1
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• pp.1-12
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• 2024

Many abnormal climate events are occurring around the world. The cause of abnormal climate is related to temperature. Factors that affect temperature include excessive emissions of carbon and greenhouse gases from a global perspective, and air circulation from a local perspective. Due to the air circulation, many abnormal climate phenomena such as abnormally high temperature and abnormally low temperature are occurring in certain areas, which can cause very serious human damage. Therefore, the problem of abnormal temperature should not be approached only as a case of climate change, but should be studied as a new category of climate crisis. In this study, we proposed a model for the classification of abnormal temperature using random forests based on various meteorological data such as longitudinal observations, yellow dust, ultraviolet radiation from 2018 to 2022 for each region in Korea. Here, the meteorological data had an imbalance problem, so the imbalance problem was solved by oversampling. As a result, we found that the variables affecting abnormal temperature are different in different regions. In particular, the central and southern regions are influenced by high pressure (Mainland China, Siberian high pressure, and North Pacific high pressure) due to their regional characteristics, so pressure-related variables had a significant impact on the classification of abnormal temperature. This suggests that a regional approach can be taken to predict abnormal temperatures from the surrounding meteorological environment. In addition, in the event of an abnormal temperature, it seems that it is possible to take preventive measures in advance according to regional characteristics.

• Journal of Environmental Science International
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• v.23 no.10
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• pp.1673-1691
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• 2014

Although most natural disaster related studies conducted in Korea recently have been related to typhoons or severe rainstorms, the occurrence frequency of disasters due to windstorms or rainstorms is also high. To reduce the strong wind damage caused by strong windstorms due to climate change, basic studies of strong winds are necessary. Therefore, in this study, the types and representative cases of windstorms that were observed to have been higher than 14 m/s, which is the criterion for strong-wind warnings from the Korea Meteorological Administration, were selected from among those windstorm cases that occurred on the Korean Peninsula for 10 years to conduct a statistical analysis of them and determine their synoptic meteorological characteristics. The cases of windstorms occurring on the Korean Peninsula were divided into six weather patterns according to the locations of the anticyclones/cyclones. Among these types, the SH type, which occurs when Siberian Highs expand into the Korean Peninsula, showed the highest occurrence frequency, accounting for at least the majority of the entire occurrence frequency of windstorms together with that of the EC type, which occurs when cyclones develop on the East Sea, and there was no clear yearly trend of the occurrence frequencies of windstorms. The monthly occurrence frequencies of windstorms were formed mainly by typhoons in the summer and the Siberian Highs in the winter, and the months with the highest windstorm occurrence frequencies were December and January, in which mainly the SH and EC type windstorms occurred. March showed the next highest occurrence frequency with10 times, and SH windstorms occurred the most frequently in March, followed by the CC, SC, and EC types of windstorms, in order of precedence. Therefore, attention to these types of windstorms is required. Countermeasures against storm and flood damage in Korea targeting the summer should be re-reviewed together with pre-disaster prevention plans, because cases of storm and flood damage due to windstorms occur more frequently than those due to typhoons, and they occur throughout the year.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1019-1024
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• 2004

The present paper is focused on simultaneous sorption concentration of gold (III) and silver (I) from thiocyanate solutions using high-selective anion exchanger AN-25 and subsequent separation of these ions at various concentrations of thiocarbamide (eluent). As a result, silver (I) ions are completely eluted from AN-25 and gold (III) ions remain in the resin phase and can be determined directly in the solid phase by diffuse reflection spectroscopy. It is proposed to use the sorption-spectroscopic method for Au(III) determination in aqueous solutions. The calibration curve is linear in the concentration range of 1-19 mg/L (sample volume is 10.0 mL) and the detection limit is 0.05 ${\mu}g/mL$. The presence of Cu(II), Co(II), Fe(II) do not hinder this determination. Au(III) was determined in industrial solutions.

• Korean Journal of Veterinary Service
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• v.20 no.1
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• pp.95-102
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• 1997

Author investigated internal parasitism for the feces of dog's training center, breeding-dog farm, dairy farm, home by 120 indoor breeding dog and 566 outdoor one in Inchon area. This survey was done from February in 1994 to December in 1995. 1. As a result of total 686 samples, positives were 373(54.4%). Among them, indoor and outdoor breeding dogs were 21(3.1%) 352(51.3%), respectively. 2. According to breeding, it was manifested that 21samples (17.5%) of 120 indoor breeding dogs were positive, and 352 samples(62.2%) of outdoor breeding were positive. 3. The infection rate of dogs for food in dairy farm, breeding dogs in the farm, dog of training center and dog of house is high in order. 4. Infection rate of parasites in 24 dogs breeds, Mongrel dogs were 81.3%, Shepherds were 80.0%, Tosas were 78.4%, Akida and Siberian huskys were 76.2%, Jindos were 55.5%, Pointers were 50.0%, although Afghan hound, Spanial, Shin-tzu, Maltis and Buldog were examined as aparasites negative. 5. After administration with vermicide parasites infection rate were 43.0% in two months. In four months, it were 66.7%, and dogs without vermicide were 87.0%. It seemed like that further research about dosage of vermicide is needed. 6. The rate of single-infection was 37.6% and that of mixed-infection was 16.8%. Among classified 13 types, Ancylostoma caninum 35.6%, Toxocara cams 11.2%, Isospora sp 9.3%, Toxascaris leonina 5.1%, Trychuris vulpis 4.4% were investigated.

• Journal of Korean Society of Forest Science
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• v.97 no.2
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• pp.144-151
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• 2008

Using 8 isozyme polymorphic loci as gene markers, we studied the spatial distribution of genotypes in a naturally regenerated uneven-aged Eastern Siberian Fir (Abies nephrolepis Max.) stand (1ha, $100{\times}100m$) on Mt. Ohdae in northeastern South Korea. Gregorius' distograms and Moran's I correlograms revealed no evidence of significant genetic structure at three spatial classes of 5 m, 10 m, and 20 m. Extensive gene flow, due to the long distance dispersal of pollen and seeds in A. nephrolepis, may account for the lack of fine-scale spatial structure. Alternatives would be overlapping seed shadows caused by high densities of A. nephrolepis adult trees (160 trees/ha) and/or intraspecific competition resulting in extensive thinning within maternal half-sib groups.

• Journal of Microbiology
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• v.37 no.1
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• pp.10-13
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• 1999

The bacterial abundance, proportion of respiring bacteria, and bacterial community of southern Lake Baikal were analyzed at 1 m and 400m depths during winter. The total bacterial numbers were 5.1${\times}$105 cells ml-1 at 1 m and 2.5${\times}$105 cells ml-1 at 400 m depth, which are about half and quarter of the numbers of other lakes. The proportion of respiring bacteria was as low as 2.5% at 1 m and 1.4% at 400 m depth. Considering the amount of organic carbon which need to be degraded and low proportion of respiring bacteria, the bacteria could be assumed to have high activities. The EUB/DAPI ratios were 77 and 89% at 1 m and 400 m depths, respectively. Of the bacterial community, the other group was dominant at both depths, and gamma group of protebacteria followed next. But the beta group of proteobacteria and Cytophaga-Flavobacterium groups occupied very small proportions.