• 한국대기환경학회지
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• 제24권1호
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• pp.83-90
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• 2008

In order to clarify the urbanization intensity of Daegu Metropolitan and its characteristics, comparative study on the variation of the cooling rate of two different sites was carried out using observation data for 40 years by Korea Meteorological Adminstration. Daegu Metropolitan and Chupungnyung represent well urbanized and rural areas, respectively. In comparison with Chupungnyung, yearly mean temperature at Daegu Metropolitan increases rapidly and especially the differences of minimum temperature increasing rate during 40 years becomes greater. These differences of regional warming are caused by the different urbanization intensity between two sites. And the impact of anthropogenic heat due to urbanization should be stronger in nighttime than in daytime. Sensible heat advection by regional wind during 6 hours from 18 LST contributes to atmospheric cooling. For this reason wind speed is in proportion to cooling rate of atmosphere. However, wind after 24 LST induces the warm air advection and makes decrease the cooling rate in urban area. Although the cooling rates between Daegu Metropolitan and Chupungnyung are some different, the variation tendencies of cooling rate of two site are almost same. Therefore atmospheric cooling rate in nighttime tends to be associated with the intensity of wind speed.

• 한국대기환경학회지
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• 제22권1호
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• pp.99-106
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• 2006

Aircraft measurements have been executed for the purpose of monitoring the long range transported air pollution and estimation of air pollutant in/out-flux over the Yellow sea. Total 74 missions of measurements have been done since 1997, mainly in spring and fall. The main study domain was over $124^{\circ}$E $/sim$ $124^{\circ}$E, $35^{\circ}$N $/sim$ $37^{\circ}$N below 3,000m. In long-term trends, mixing ratios of $SO_{2}$N were around 2 ppbv expect in summer ( < 1 ppbv). NOx exhibited 24 ppbv and have no clear annual trends over the Yellow Sea. The concentrations of 03 were 51, 58, 41 ppbv in spring, summer and fall-winter, respectively. Backward trajectory was performed for three days to investigate the source regions of the air mass. Six regions were divided around Korea peninsular centering at $36^{\circ}$N, $126^{\circ}$E. I, II, III, IV and V regions represents in sequence northeast China and Siberia, Sandong peninsula and Balhae gulf, Sanghi and southern China, the south Pacific included Jeju island and the East sea included Japan. L region correspond to the airmass from Korea peninsula. Influx of $SO_{2}$N was approximately five times higher than outflux in yearly flux variation and showed a decreasing long-term trend since 1998. NOx outflux was average 0.095 ton/km/hr and three times higher than $SO_{2}$ outflux. In/out flux of 03 showed even distribution in yearly basis except 2002 (influx 5.45 ton/km/hr). The transported amounts from I, II, III regions were much higher than those from other region. In seasonal flux variation, influx levels of gas phases were the lowest in summer and the levels gradually increased from fall toward spring. As a result, transport of pollutants begins from fall and prevails in winter and spring.

• 한국농림기상학회지
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• 제4권3호
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• pp.164-168
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• 2002

우리나라 벼 수량 기상반응의 최대경계선 분석을 통하여 구축한 벼 수량예측모델(금 등, 2001)의 지역, 연차 및 품종의 수량 변이 예측 정확도를 검증한 결과는 다음과 같다. 1. 모형구축에 이용된 전국 20개 지역의 지역별 15년 간의 평균수량은 실측치와 예측치 간에 r=0.9296$^{**}$ 으로 고도로 유의한 상관을 나타내고 있으며 모형작성에서 제외시켰던 12개 지역 평균수량의 예측치와 실측치간의 상관계수도 r=0.8923$^{**}$ 으로 모형작성에 이용된 지역보다 수량예측의 정확도가 다소 낮게 나타났으나 통계적으로 고도로 유의하였다. 2. 모형설정에 사용된 20개 지역과 사용되지 않는 12개 지역 모두 연차별 실제수량과 예측수량간에는 고도로 유의한 상관이 존재하여 수량의 연차간 변이를 잘 예측하였다. 다만 냉해년에는 다소과대 추정하는 경향이었다. 3. 동진벼, 화성벼, 추청벼 등의 8개 품종별로 실제 수량과 예측수량간에는 고도로 유의한 상관이 있었다. 다만 모형구축에 이용되지 않은 지역의 자료를 이용하는 경우 모형설정에 이용한 자료를 이용한 경우보다 다소 상관이 낮아졌다. 4. 결론적으로 수량기상반응의 최대경계선(boundary line)분석은 수량 예측 모형의 구축에 효율적으로 적용될 수 있을 것으로 판단되었으며, 본 연구에서 고려하지 않은 토양조건, 시비조건 등에 대한 최대경계선 분석을 포함시키는 경우 보다 정확도가 높은 수량예측모형을 작성할 수 있으며 이를 통한 지성, 년도, 품종에 따른 수량의 변이를 실용적으로 예측할 수 있을 것으로 기대된다.

• 대한원격탐사학회지
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• 제33권5_2호
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• pp.699-708
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• 2017

본 연구에서는 재배 방법, 토양 특성 등의 정보를 상세하게 수집하기 어려운 지역단위의 콩 작황을 작물생육 모델을 이용하여 예측하는 방법을 개발하고자 하였다. 작물 생육 모델은 DSSAT에 포함된 CROPGRO-Soybean 모델을 이용하였고, 미국의 주요 콩 생산지역인 Illinois주를 연구 사례지역으로 선택하였다. CROPGRO-Soybean 모델을 이용하여 Illinois주의 콩 수량을 예측하기 위한 첫 단계로 다양한 성숙군에 속하는 국내외 품종들을 수집하여 서울대학교농장($37.27^{\circ}N$, $126.99^{\circ}E$)에서 2년동안 파종기 실험을 하여 성숙군(maturity group) I~VI까지의 성숙군별 대표 품종모수(genetic coefficients)를 추정하였다. 대표 품종모수는 각 성숙군 내에 포함되어 있는 품종들의 발육을 매우 정확하게 추정하였다. $10km{\times}10km$ 격자 단위의 기상자료를 바탕으로 성숙군(3), 파종시기(3), 관개여부(2) 등을 조합하여 18가지 조건으로 2000년에서 2011년까지 수량을 각각 모의 하였다. 성숙군과 파종시기는 Illinois주를 위도에 따라 3등분하여 각각 다르게 설정하였다. 관개 및 무관개 조건으로 구분하여 격자 별 모의결과로부터 Illinois주 전체 평균 모의수량을 구하여 연도 별 통계 수량과 비교한 결과 두 경우 모두 실제 수량과 큰 차이를 보일 뿐만 아니라 연차에 따른 수량 변동과 증가 경향을 반영하지 못하였다. 이러한 한계를 극복하고자 처리 별 격자 별로 모의된 수량을 수량을 18개 모의 조건 별로 평균하여 구한 9개 농업지구의 연도별 수량을 독립 변수, 농업지구의 연도별 통계수량을 종속 변수로 하는 중회귀 모델을 구축하였다. 18개 모의 조건 별 수량 외에 품종 개량, 재배 기술 발전 등에 따른 수량의 연차적 변화경향을 반영하기 위하여 연도를 독립변수로 추가하였으며, 중회귀모델은 농업지구와 연도별 수량 변이를 비교적 잘 예측($R^2=0.61$, n=108)하였다. 중회귀 모델로 추정한 9개 농업지구의 연도별 수량을 농업지구별 재배 면적으로 가중 평균한 Illinois의 연도별 추정수량은 통계수량에 매우 근사하였다($R^2=0.80$). 뿐만 아니라 모델 구축 대상연도가 아니고 가뭄으로 수량이 크게 감소한 2012년의 예측 수량은 $3006kg\;ha^{-1}$로 통계수량 $2890kg\;ha^{-1}$과 $116kg\;ha^{-1}$의 근사한 차이를 보였다.

• 한국환경과학회지
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• 제11권12호
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• pp.1281-1289
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• 2002

This study was conducted to evaluate water quality in the Keum River using multivariate analysis. The analysis data in Keum river made use of surveyed data by the ministry of environment from January 1994 to December 2001. Thirteen water quality parameter were determined on each sample. The results was summarized as follow; Water quality in the Keum River could be explained up to 71.39% by four factors which were included in loading of organic matter and nutrients by the tributaries (32.88%), seasonal variation (16.09%), loading of pathogenic bacteria by domestic sewage of Gapcheon (13.39%) and internal metabolism in estuary as lakes(9.03%). For spatial variation of factor score, four group was classified by each factor characterization. Station 1 and 2 was influenced by Daechung dam, station 3 was affected by domestic sewage of Gapcheon, station 10~12 was affected by estuary dyke and the rest station. The result of cluster analysis by station was classified into four group that has different water quality characteristics. In monthly cluster analysis, three group was classified according to seasonal characteristic. Also, in yearly cluster analysis, three group was classified. It is necessary to control the pollutant loadings by Gapcheon inflow domestic sewage in Daejeon city for the sake of water quality management of Keum river.

• 미생물학회지
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• 제22권3호
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• pp.157-165
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• 1984

Seasonal and spatial variations in propagule numbers of Trichoderma species were investigated every other month for one year in deciduous and coniferous forest soils and evaluated the relationships of Trichoderma spp. populations to soil environmental factors. The total population of Trichoderma spp. increased until summer and then declined until winter. The yearly mean frequency of Trichoderma spp. exceeded 1.4% of total fungal propagules in two sites. Decreases of absolute an relative propagule numbers of Trichoderma spp. with increasing soil depth were found and variation in Trichoderma spp. propagules caused by differences in soil depth ($0{\sim}50cm$) was greater than that caused by differences in sampling time. The most common species occurring in two sites was T. viride, followed by T. polysporum, T. koningii, and T. hamatum. Individual species of Trichoderma showed diferent abundance trend in accordance with sampling time. T. viride was dorminant from spring to autumn, while T. polysporum dominated over the other speicies in winter. Variations in propagule number of Trichoderma sppp. were principally mediated by the actions of biotic environmental factors rather than by the direct effects of abiotic factors. In multiple-regression analyses, 48% of the total vaiation in Trichoderma spp. propagules in deciduous site could be accounted for by total fungal propagules and soil CMCase actvity. In coniferous site, 65% of total variation could be accounted for by total fungal and bacterial propagules, moisture content and organic carbon content.

• 한국물환경학회지
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• 제24권1호
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• pp.44-53
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• 2008

To recognize the spatial and temporal variability of water temperature and dissolved oxygen in the Youngsan reservoir formed after dike construction, water temperature and dissolved oxygen data have been observed and analyzed from April, 2002 until March, 2003. As the results, certain stratifications were not distinctly observed in the Youngsan reservoir during summer, which was estimated due to the drainage characteristic from the Youngsan water gates. The yearly variation of water temperature in the Youngsan reservoir is shown seasonally ups and downs by the heat exchange between the atmosphere and the reservoir. On the other hand, dissolved oxygen and water temperature in the Youngsan reservoir have been shown inversed proportional correlation. As the calculation results of residence time and water exchange rate, it is considered that the feature of oxygen distribution is determined by the drainage characteristics caused the shortest residence time during summer, which also disturbed the formation of stratification in the Youngsan reservoir.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.14-14
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• 2022

Greenhouse gas emissions are one of the critical factors that drive change in rice cropping systems. Within this changing system, less water irrigation and chemical fertilizer are seriously considered, as well combining precision farming technologies with irrigation control. Water and phosphorus (P) fertilizer are two of the most critical inputs in rice cultivation. Due to the lack of water availability in the system, P fertilizer is not available, especially in acidic soil conditions. Moreover, the various types of abiotic stresses, such as drought, high temperature, salinity, submergence, and limited fertilizer result in significant yield loss in the system. Even in the late stage of growth, the waves caused by diseases and insects make the field more unfruitful. Therefore, agronomists and breeders need to identify the secondary phenotypes to estimate the yield loss of when stress appears. The prediction will be clearer if we have a set of markers tagging the causal variation and the associated precise phenotype indices. Although there have been various studies for abiotic stress tolerance, we still lack functional molecular markers and phenotype indices. This is due to the underlying challenges caused by environmental factors in highly unpredictable regional and yearly environmental conditions in the field system. Pupl (phosphorus uptake 1) is still known as the first QTL associated with phosphorus uptake and have been validated in different field crops. Interestingly, some pyramiding lines of Pupl and other QTLs for other stress tolerances showed preferable phenotypes in the yield. Precise physiological studies with the help of genomics are on-going and some results will be discussed.

• 한국약용작물학회지
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• 제2권1호
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• pp.7-13
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• 1994

1983년(年) 부터 1992년(年) 까지 계속하여 재배(栽培)하여온 전남(全南) 승주군(昇州郡) 해룡면(海龍面) 농가(農家) 도장(圖場)에서 조사(調査)한 택사(澤瀉)의 주요특성(主要特性)과 재배기간중(栽培期間中) 관측(觀測)된 기상자료(氣象資料)를 이용(利用)하여 생육(生育) 및 수양(收量)과 기상요인(氣象要因)과의 상관관계(相關關係), 분산(分散) 및 수양(收量) 추정식(推定式)을 유도(誘導)한 결과(結果)는 다음과 같다. 1. 기상요인중(氣象要因中) 변리(變異)가 큰 것은 10월(月) 의 강수량(降水量)과 11월(月)의 최저기온(最低氣溫)으로서 변리계수(變異係數) (C.V)는 각각 106.44%와 144.08%였으며, 7월(月), 8월(月), 9월(月)의 평균기온(平均氣溫)과 최고기온(最高氣溫) 및 최저기온(最低氣溫)은 비교적 변리(變異)가 적었다. 2. 생육(生育) 및 수양형질(收量形質)의 변리계수(變異係數)는 수양형질중(收量形質中) 생근중(生根重)은 30.62% 건근중(乾根重)은 31.8%서 년차간(年次間) 변리(變異)가 아주 켰고 묘장(苗長)과 경장(莖長)은 $5.51{\sim}6.26%$로 변리(變異)가 중간정도였으며 엽폭(葉幅), 엽장(葉長), 경수(莖數) 및 근경(根莖)은 $1.08%{\sim}3.23%$로 변리(變異)가 아주 적어서 이들 형질(形質)은 년차간(年次間) 변리(變異)가 적음을 알 수 있었다. 3. 기상요인(氣象要因) 택사생육(澤瀉生育) 및 수양형질간(收量形質間)의 상관(相關)에서는 11월(月)의 최고기온(最高氣溫)과 엽장(葉長), 경장(莖長), 경수(莖數), 및 건근중(乾根重)에서 5% 수준(水準)의 유의성(有意性) 있는 정(正)의 상관(相關)이 인정(認定)되었다. 4.생육(生育) 및 수양형질(收量形質) 상호간(相互間)의 상관(相關)에서는 모두가 정(正)의 상관(相關)으로 고도(高度)의 유의성(有意性)이 인정(認定)되었으며 11월(月)의 최고기온(最高氣溫)을 이용(利用)하여 경수(莖數)를 추정(推定)한 결과(結果) $Y_1=4.114+0.5333\;X\;(R^2=0.4410)$,의 직선회귀식(直線回歸式)을 유도(誘導)할 수 있었고, 역시 11월(月)의 최고기온(最高氣溫)을 이용(利用)하여 건근중(乾根重)수양(收量)의 추정식(推定式) 유도(誘導)한 결과(結果)$Y_2=55.0405+14.3233\;X\;(R^2=0.4511)$의 직선회귀식(直線回歸式)을 얻을 수 있었으며 이들에 대한 분산(分散) 분석(分析)에서도 유의성(有意性)이 인정(認定)되었기에 수양(收量)에 대한 추정식(推定式)을 이용(利用)하여 이논적(理論的) 수양(收量)과 실제수양(實際收量)의 오차(誤差)를 구(求)한 결과(結果) l0%미만(未滿)의 차이(差異)를 보여 비교적 잘 적중되었다.

• Journal of Astronomy and Space Sciences
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• 제36권3호
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• pp.159-168
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• 2019

In solstices during the solar minimum, the hemispheric difference of the equatorial ionization anomaly (EIA) intensity (hereafter hemispheric asymmetry) is understood as being opposite in the morning and afternoon. This phenomenon is explained by the temporal variation of the combined effects of the fountain process and interhemispheric wind. However, the mechanism applied to the observations during the solar minimum has not yet been validated with observations made during other periods of the solar cycle. We investigate the variability of the hemispheric asymmetry with local time (LT), altitude, season, and solar cycle using the electron density taken by the CHAllenging Minisatellite Payload satellite and the global total electron content (TEC) maps acquired during 2001-2008. The electron density profiles provided by the Constellation Observing System for Meteorology, Ionosphere, and Climate satellites during 2007-2008 are also used to investigate the variation of the hemispheric asymmetry with altitude during the solar minimum. During the solar minimum, the location of a stronger EIA moves from the winter hemisphere to the summer hemisphere around 1200-1400 LT. The reversal of the hemispheric asymmetry is more clearly visible in the F-peak density than in TEC or in topside plasma density. During the solar maximum, the EIA in the winter hemisphere is stronger than that in the summer hemisphere in both the morning and afternoon. When the location of a stronger EIA in the afternoon is viewed as a function of the year, the transition from the winter hemisphere to the summer hemisphere occurs near 2004 (yearly average F10.7 index = 106). We discuss the mechanisms that cause the variation of the hemispheric asymmetry with LT and solar cycle.