• 한국대기환경학회지
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• 제31권2호
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• pp.181-194
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• 2015

Spatial-temporal meteorological features of the Ulsan metropolitan region (UMR) were analyzed using observations and high-resolution numerical modeling. Long-term trend analysis (1970~2013) showed a significant increase of $0.033^{\circ}Cyr^{-1}$ in the 5-year moving average temperature, although detailed short-term features varied, whereas wind speed and relative humidity over the same period displayed clear decreases of $-0.007ms^{-1}$ and $-0.29%yr^{-1}$, respectively. These trends indicate the effects of regional climate change and urbanization in the UMR. Seasonal variations averaged for the most recent three years, 2011~2013, showed that temperatures in three different regions (urban/industrial, suburban, coastal areas) of the UMR had similar seasonality, but significant differences among them were observed for a certain season. Urban and industrial complex regions were characterized by relatively higher temperatures with large differences (max.: $3.6^{\circ}C$) from that in the coastal area in summer. For wind speed, strong values in the range from 3.3 to $3.9ms^{-1}$ occurred in the coastal areas, with large differences clearly shown between the three regions in September and October. Diurnal variations of temperature were characterized by pronounced differences during the daytime (in summer) or nighttime (in winter) between the three regions. Results from the WRF modeling performed for four months of 2012 showed large variations in gridaverage temperature and winds in the UMR, which displayed significant changes by season. Especially, a clear temperature rise in the urban center was identified in July ($0.6^{\circ}C$ higher than nearby urban areas), and overall, relatively weak winds were simulated over urban and inland suburban regions in all seasons.

• The Korean Journal of Ecology
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• 제18권3호
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• pp.323-332
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• 1995

Effects of wintering and temperature on nitrogen fixation activity of nodules of Melilotus suaveolens Ledeb. grown in the field and growth chamber conditions were investigated. The biennial plants transfered to the growth chamber from winter field recovered the activity in 3 weeks of incubation and attained the maximum rate of $153{\mu}mol\;C_2H_4{\cdot}g$ fr wt $nodule^{-1}{\cdot}h^{-1}$ in 5 weeks. When root nodules which adapted to different temperatures, were pretreated with 10, 20 and $30^{\circ}C$ for 1 hour, and then transfered to $30^{\circ}C$, nitrogen fixation activity was promoted in the nodules exposed to lower field temperature ($12^{\circ}C$) with 1$0^{\circ}C$ pretreatment. M. suaveolens maintained nitrogen fixation activity in the wide range of temperatures, and was more tolerant to lower temperature than those of other woody leguminous plants, Diurnal changes of nodule activity showed increase with sunrise and decrease with sunset during spring and autumn, but the activity was inhibited during July and August because of high temperature with stron irradiation. Nitrogen fixation activity of annual plant appeared in mid-April, and showed two peaks (104 and 43 mol $C_2H_4{\cdot}g$ fr wt $nodule^{-1}{\cdot}h^{-1}$) in July and September, and then disappeared after October. Nitrogen fixation activity of biennial plant reappeared in mid-March after wintering and attained two peaks (102 and 82 ${\mu}mol\;C_2H_4{\cdot}g$ fr wt $nodule^{-1}{\cdot}h^{-1}$) in April and June of flowering period, and then disappeared after July due to plant withering by severe drought.

• 한국환경과학회지
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• 제12권8호
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• pp.853-860
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• 2003

Plants sequester atmospheric CO$_2$, a major agent of climate change, during the growing periods and mitigate its rising accumulation in the atmosphere. Pinus densiflora and Quercus mongolica are the native tree species dominant in the temperate forests of Korea. This study quantified the annual CO$_2$ uptake by the two species at forest sites in Chuncheon in the middle of the country. The quantification was based on seasonal measurements of CO$_2$ exchange rates under natural conditions by an infrared gas analyzer over the growing season (1999). The monthly CO$_2$ uptake per unit leaf area ranged from 1.6-6.7 mg/d㎡/h for P. densiflora and from 3.7-8.9 mg/d㎡/h for Q. mongolica, with a maximum in mid-summer. An equation for each species was generated to estimate easily the annual CO$_2$ uptake by total leaf area per tree, which subtracted the CO$_2$ release (i.e. respiration) by leaves and woody organs from the gross CO$_2$ uptake (diurnal uptake and release by leaves). Annual CO$_2$ release by leaves and woody organs accounted for 58-73％ of the gross CO$_2$ uptake across tree specimens. Annual CO$_2$ uptake per tree increased with increasing dbh (stem diameter at breast height) for the study diameter range, and was greater for Q. mongolica than for P. densiflora in the same dbh sizes. This was mainly associated with a greater total leaf area in the former. For example, the annual CO$_2$ uptake by one tree with dbh of 25 cm was 35.6 kg/yr for P. densiflora and 47.9 kg/yr for Q. mongolica. The results from this study can be applied to evaluate an atmospheric CO$_2$ reduction of woody plants by forest type and age class.

• Journal of the Korean Data and Information Science Society
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• 제28권1호
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• pp.131-142
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• 2017

매년 폐렴 입원 환자 수는 증가하는 추세이며, 국내 질환 중 입원율 1위이기도 하다. 주로 박테리아와 바이러스가 주된 원인인 폐렴은 날씨의 영향을 받기도 한다. 본 연구에서는 날씨 변수로는 습도, 일조량, 일교차, 평균온도, 미세먼지 농도를 각각 1일 전부터 27일 전까지의 총 135개 변수를 고려하였다. 날씨와 입원 환자 수에 잠재적으로 영향을 미치는 위험 요인으로 연도 효과, 휴일 효과, 계절 효과를 추가적으로 고려하였다. 벌점화 일반화 선형 모형을 이용하여 폐렴 입원 환자 수와 관련된 변수를 선택하였다.

• 대기
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• 제23권4호
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• pp.413-424
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• 2013

Urban Heat Island (UHI) intensity is one of vital parameters in studying urban boundary layer meteorology as well as urban planning. Because the UHI intensity is defined as air temperature difference between urban and rural sites, an objective sites selection criterion is necessary for proper quantification of the spatial variations of the UHI intensity. This study quantified the UHI intensity and its spatial pattern, and then analyzed their connections with urban structure and metabolism in Seoul metropolitan area where many kinds of land use and land cover types coexist. In this study, screen-level temperature data in non-precipitation day conditions observed from 29 automatic weather stations (AWS) in Seoul were analyzed to delineate the characteristics of UHI. For quality control of the data, gap test, limit test, and step test based on guideline of World Meteorological Organization were conducted. After classifying all stations by their own local climatological properties, UHI intensity and diurnal temperature range (DTR) are calculated, and then their seasonal patterns are discussed. Maximum UHI intensity was $4.3^{\circ}C$ in autumn and minimum was $3.6^{\circ}C$ in spring. Maximum DTR appeared in autumn as $3.8^{\circ}C$, but minimum was $2.3^{\circ}C$ in summer. UHI intensity and DTR showed large variations with different local climate zones. Despite limited information on accuracy and exposure errors of the automatic weather stations, the observed data from AWS network represented theoretical UHI intensities with difference local climate zone in Seoul.

• 한국어류학회지
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• 제13권1호
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• pp.32-39
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• 2001

대천 해빈 쇄파대에서 1990년 8월 사리와 조금 때 2시간 간격으로 24시간 동안 어류를 채집하여, 조차, 조위 밤낮에 따른 어류 종조성의 단기 변동을 분석하였다. 채집된 어류는 총 24종으로, 부어류의 유어들이 양적으로 많았고, 사리 간조 때에는 저어류의 유어들도 출현하였다. Wilcoxon의 signed-rank test 결과 사리 때가 조금 때에 비하여 유의하게 많은 양이 채집되었다. 사리 때에 는 만조 때에 비하여 간조 때 유의하게 많은 어류가 채집되었으나, 조금 때에는 간조와 만조 때 유의한 차이를 보이지 않았다. 부어류들의 평균 개체수는 사리와 조금 때 유의한 차이를 보이지 않았지만, 대부분의 저어류들은 사리 간조 때에 유의하게 많이 잡혔다. 채집된 대부분의 저어류들은 사리 간조 때 대부분 채집되어, 저어류들은 대부분이 조금 때 간조선 보다 깊은 곳에 서식하는 것을 알 수 있다.

• 한국대기환경학회지
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• 제24권5호
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• pp.584-593
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• 2008

The surface $O_3,\;CO,\;NO_x,\;and\;SO_2$ were measured at Gosan in Jeju Island from May 2004 to April 2005. Over this period, the mean concentrations $({\pm}s.d.)$ of each gas was 40.06 $({\pm}16.01)$ ppbv for $O_3,\;264.92({\pm}115.73)ppbv\;for\;CO,\;1.98({\pm}2.73)ppbv\;for\;SO)_2,\;and\;4.64 ({\pm}3.24) ppbv\;for\;NO_x$. The monthly variations and the diurnal variations of these gases show that the Gosan site is situated in a relatively clean region. However, there were episodic simultaneous peaks in CO and $SO_2$, especially in winter and early spring. Using cluster analysis with air mass back- ward trajectory analysis, we suggest that these episodes are due to the influence of transportation of polluted air mass from polluted regions. In the cluster, which was under the dominant influence of clean maritime air mass, low levels of $O_3,\;CO,\;and\;SO_2$ were observed. The levels of these species were elevated in the other two clusters which had the air mass influenced by polluted continental regions. In addition, ratios of the chemical species such as $CO/NO_x,\;SO_2/NO_x,\;and\;CO/SO_2$ revealed the somewhat different characteristics of emission sources influencing each cluster. The differences in concentration of trace gases among clusters with different origin and transport pathways imply that Gosan is under the effect of pollution transported from other regions.

• 한국동물학회지
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• 제15권2호
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• pp.87-91
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• 1972

西部 北太平洋에 있어서의 本種에 대한 地理分布와 垂直分布 및 晝夜垂直移動에 관한 知見은 극히 限定된 海域과 深度에 있어서의 報告가 있을 뿐이다. 筆者는 北緯 20度에서 47度에 이르는 東經 50度 以西의 西部 北太平洋과 이의 附屬海에 걸친 광범위한 調査를 통하여 本種의 地理分布에 관한 새로운 知見을 얻었다. 그 結果로 東支那海의 表層을 제외한 68地點에서 本種이 出現함으로써 浮游性 端脚類中에서도 唯一하게 西部 北太平洋 全域에 걸쳐 一樣하게 分布하고 있으며 季節的인 消長이 없음이 究明되었다. 한편 垂直的으로는 0 $\\sim$ 1,500m 以上에 分布하고 있으며 最深採集記錄은 定點 229 $(34^\\circ 44.3'N, 140^\\circ 04.4'E)$에서의 1,650 $\\sim$ 2,220m層에서 얻어졌다. 晝夜垂直移動의 類型을 보면 本種은 晝間에는 深層部에 分布하며 夜間에 表層部로 현저한 晝夜移動을 하고 있음을 밝혔다. 이 移動의 範圍는 100 $\\sim$ 200m에 달한다. 또한 黑潮域에서는 新潮域에 비하여 垂直分布의 深度가 얕으며 서로 垂直分布의 深度와 移動의 範圍가 다르다. 즉 黑潮域에서는 晝間 0 $\\sim$ 200m層에 夜間 100 $\\sim$ 300m層에 個體群의 中心이 分布하며 100m의 範圍로 垂直移動을 하는데 反하여 新潮域에서는 晝間 400 $\\sim$ 700m, 夜間 100 $\\sim$ 500m로 200m의 範圍로 移動한다. 이는 兩海域에 있어서의 個體群의 組成이 서로 다른데 起因되는 결과로 사료된다.

• 한국환경과학회지
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• 제13권12호
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• pp.1079-1088
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• 2004

In order to understand chemical characteristics and dewfall formation in western Busan area, we analysed monthly distribution of dewfall, and investigated the correlation between dewfall formation amount and meteoro­logical factors. This study used the modified teflon plate $(1m{\times}1m)$ at Silla university in Busan from August 2002 to April 2003. In order to estimate qualitatively water soluble components, IC, ICP and UV methods for water soluble ions are also used respectively. Dewfall amount of sampling periods (47 day) collected 3.8 mm. Meteorological conditions for the formation of dewfall above $50\;g/m^{2}$ showed that temperature diurnal $range(^{\circ}C)\;was\;5.6^{\circ}C$ above, cloud amounts (1/10) at dawn of the sampling day was 7/10 below, mean wind speed at dawn (0~6hr) of the sampling day was 4.4 m/sec below, and mixing ratio at 6hr of the sampling day was 3.2 g/kg above. Distribution of water soluble ions in dewfall founded the highest concentration (206.1\;{\mu}eq/{\ell}\;for\;SO_{4}^{2-},\;42.4\;{\mu}eq/{\ell}\;for\;NH_{4}^{+},\;249.2\;{\mu}eq/{\ell}\;for\;Ca^{2+},\;and\;42.0\;{\mu}eq/{\ell}\;for\;Mg^{2+})$ during the March, the lowest concentration $(73.0\;{\mu}eq/{\ell}\;for\;SO_{4}^{2-},\;4.6\;{\mu}eq/{\ell}\;for\;NH_{4}^+\;and\;72.7\;{\mu}eq/{\ell}\;for\;Ca^{2+})$ during the August. Monthly equivalent ratio of $[SO_{4}^{2-}]/[NO_{3}^-]$ showed the highest value (4.99) during the October, the lowest value (1.84) during the August, and the mean value was 3.45.

• 대기
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• 제27권2호
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• pp.235-249
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• 2017

This paper describes methodology verifying near-surface predictability of numerical weather prediction models against the surface synoptic weather station network (SYNOP) observation. As verification variables, temperature, wind, humidity-related variables, total cloud cover, and surface pressure are included in this tool. Quality controlled SYNOP observation through the pre-processing for data assimilation is used. To consider the difference of topographic height between observation and model grid points, vertical inter/extrapolation is applied for temperature, humidity, and surface pressure verification. This verification algorithm is applied for verifying medium-range forecasts by a global forecasting model developed by Korea Institute of Atmospheric Prediction Systems to measure the near-surface predictability of the model and to evaluate the capability of the developed verification tool. It is found that the verification of near-surface prediction against SYNOP observation shows consistency with verification of upper atmosphere against global radiosonde observation, suggesting reliability of those data and demonstrating importance of verification against in-situ measurement as well. Although verifying modeled total cloud cover with observation might have limitation due to the different definition between the model and observation, it is also capable to diagnose the relative bias of model predictability such as a regional reliability and diurnal evolution of the bias.