• Journal of the Korean Data and Information Science Society
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• 제20권6호
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• pp.1085-1092
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• 2009

지표오존 농도는 국가의 중요한 환경 척도 중의 하나이다. 본 연구에서는 경기도 파주시 오존농도를 자기회귀오차모형과 신경망모형으로 분석하였다. 오존 분석을 위한 설명변수로는 이산화황, 이산화질소, 일산화탄소, 프로메툼10 등의 대기자료와 일 최고온도, 풍속, 상대습도, 강수량, 이슬점온도, 운량, 수증기압 등의 기상자료를 사용하였다. 분석 결과 전반적으로 신경망모형이 좋은 모형으로 나타났고, 자기회귀오차모형도 오존에 영향을 주는 설명변수를 첨가하면 좋은 모형이 될 것으로 생각된다.

• 정보과학회 논문지
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• 제42권3호
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• pp.281-288
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• 2015

화산재해 피해 예측 시스템은 기상과 화산분화 시뮬레이션 결과를 기반으로 화산재해대응을 위한 판단을 도와주는 시스템이다. 이 시스템에서 Fall3D라는 프로그램은 기상정보를 바탕으로 화산분화 이후 화산재의 확산예측결과를 생성하고 기상정보를 생성하기 위해 WRF라는 기상수치예보모델을 사용한다. 두 시뮬레이션의 프로그램을 수정하지 않고, 전체 실행시간을 줄이기 위해서는 WRF의 기상예측모델의 시간별 부분결과가 발생할 때마다 Fall3D를 부분수행 할 수 있도록 하는 파이프라이닝 방식을 생각할 수 있다. 이를 위해서 Fall3D와 같은 후속계산은 선행계산의 부분결과가 생성될 때까지 일시정지하고, 계산에 필요한 정보가 발생하면 재개할 수 있어야한다. 비록 Fall3D가 이런 일시정지와 재개기능을 가지고 있지는 않지만 그 이전 계산을 이어서 진행할 수 있는 재시작기능을 활용하여 파이프라이닝 효과를 낼 수 있다. 본 논문에서는 이러한 실행 형태를 제어할 수 있는 워크플로우를 제안한다.

• 대기
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• 제19권3호
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• pp.269-287
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• 2009

CAT (clear-air turbulence) forecasting algorithm, the Graphical Turbulence Guidance (GTG) system developed at NCAR (national center for atmospheric research), is evaluated with available observations (e.g., pilot reports; PIREPs) reported in South Korea during the recent 5 years (2003-2008, excluding 2005). The GTG system includes several steps. First, 44 CAT indices are calculated in the domain of the Regional Data Assimilation and Prediction System (RDAPS) analysis data with 30 km horizontal grid spacing provided by KMA (Korean Meteorological Administration). Second, 10 indices that performed ten best forecasting scores are selected. Finally, 10 indices are combined by measuring the score based on the probability of detection, which is calculated using PIREPs exclusively of moderate-or-greater intensity. In order to investigate the best performance of the GTG system in Korea, various statistical examinations and sensitivity tests of the GTG system are performed by yearly and seasonally classified PIREPs. Performances of the GTG system based on yearly distributed PIREPs have annual variations because the compositions of indices are different from each year. Seasonal forecasting is generally better than yearly forecasting, because selected CAT indices in each season represent meteorological condition much more properly than applying the selected CAT indices to all seasons. Wintertime forecasting is the best among the four seasonal forecastings. This is likely due to that the GTG system consists of many CAT indices related to the jet stream, and turbulence associated with the jet stream can be activated mostly in wintertime under strong jet magnitude. On the other hand, summertime forecasting skill is much less than other seasons. Compared with current operational CAT prediction system (KITFA; Korean Integrated Turbulence Forecasting System), overall performance of the GTG system is better when CAT indices are selected seasonally.

• 대기
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• 제27권3호
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• pp.345-358
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• 2017

The decadal change in rainfall for Changma period over the South Korea in early-2000s is detected in this study. The Changma rainfall in P1 (1992~2002) decade is remarkably less than in P2 (2003~2013) decade. The much rainfall in P2 decade is associated with the increase of rainy day frequency during Changma period, including the frequent occurrences of rainy day with a intensity of 30 mm/day or more in P2 decade. This decadal change in the Changma rainfall is due to the decadal change of atmospheric circulation around the Korean Peninsula which affects the intensity and location of Changma rainfall. During P2 decade, the anomalous anti-cyclone over the south of the Korean Peninsula, which represents the expansion of the North Pacific high with warm and wet air mass toward East Asia, is stronger than in P1 decade. In addition, the upper level zonal wind and meridional gradient of low-level equivalent potential temperature in P2 decade is relatively strengthened over the northern part of the Korean Peninsula than in P1 decade, which corresponds with the intensification of meridional gradient between air mass related to the East Asian summer monsoon nearby the Korean Peninsula in P2 decade. The enhanced meridional gradient of atir mass during P2 decade is favorable condition for the intensification of Changma rainfall band and more Changma rainfall. The atmospheric conditions related to enhanced Changma rainfall during P2 decade is likely to be influenced by the teleconnection linked to the suppressed convection anomaly over the southern part of China and South China Sea in P2 decade.

• 대기
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• 제27권3호
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• pp.291-300
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• 2017

The monthly-mean irradiance of ultra violet (UV)-B and UV-A observed from 2005 to 2014 and 2012 to 2014, respectively, at noon in Gosan, Jeju, South Korea are analyzed. We compare cloudiness, total ozone, visibility, and relative humidity with an emphasis on the four months from May to August (MJJA), which shows the largest UV radiation. While the incoming UV-B radiation at the top of the atmosphere in Gosan is the largest in June due to the small solar zenith angle, the observed surface UV-B shows an unexpected smaller value in June than those in May, July or August. In June, the meteorological conditions affecting Gosan are completely dominated by cloudiness and thus, frequent overcast seems to determine the minimum UV-B. Another important UV-determining factor is the total ozone, which exhibits a monotonic decrease during MJJA without agreeing to the characteristic feature of UV. The ratio of UV-B to UV-A is not generally influenced by cloudiness. Thus, the ratio is a useful indicator of atmospheric turbidity showing larger values for increasing visibility, except in June. A simple model has been used to estimate surface UV by using the observed ozone and visibility in the cloudless condition. The result shows that UV has the lowest value in June with small variation during MJJA. Model estimation also shows that the different characteristic features observed in July between surface UV-B and UV-A is the result of less absorption of UV-B by ozone than that of UV-A by a smaller amount of total ozone.

• 한국위성정보통신학회논문지
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• 제8권3호
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• pp.32-40
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• 2013

Boltwood 구름센서는 구름으로부터 복사되는 적외선을 감지하여 구름의 유무와 많고 적음을 판별할 수 있는 기상센서의 한 종류이다. 이 구름센서는 한국천문연구원이 진행하고 있는 국가현안과제의 일환인 우주물체 전자광학 감시체계 시스템(OWL, Optical Wide-field patroL)에 사용될 계획이다. 실제 시스템 적용에 앞서, Boltwood 구름센서를 충북대학교 천문대에 설치, 약 2주간 구름센서의 구름감지 성능 시험을 위한 관측을 진행하였다. 구름센서의 성능과 비교할 대상으로 충북대학교 천문대에 현재 설치, 운영 중인 구름량 측정을 위한 CCD 관측시스템을 이용하였다. 성능 테스트 결과, 하늘과 지상의 온도차이와 측광 자료의 별 개수간 명확한 상관관계가 도출되지 못했다. 그 원인으로는 시험 환경상의 문제와 Boltwood 구름센서의 내부 알고리즘 및 하드웨어에 대한 정보공개가 제한 때문인 것으로 판단된다. 이 논문에서는 Boltwood 구름센서와 CCD 관측시스템의 구름지수를 비교, 분석한 과정과 그 상세 결과를 제시하고자 한다.

• 한국환경과학회지
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• 제15권5호
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• pp.417-430
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• 2006

We focused on improvement in simulation of wind fields for the complex coastal area. Local Analysis and Prediction System(LAPS) was used as a data assimilation method to improve initial conditions. Case studies of different LAPS inputs were performed to compare improvement of wind fields. Five cases have been employed : I) non data assimilation, II) all available data, III) AWS, buoy, QuikSCAT, IV) AWS, buoy, wind profiler, V) AWS, buoy, AMEDAS. Data assimilation can supplement insufficiency of the mesoscale model which does not represent detailed terrain effect and small scale atmospheric flow fields. Result assimilated all available data showed a good agreement to the observations rather than other cases and estimated veil the local meteorological characteristics including sea breeze and up-slope winds. Result using wind profiler data was the next best thing. This implies that data assimilation with many high-resolution sounding data could contribute to the improvements of good initial condition in the complex coastal area. As a result, these indicated that effective data assimilation process and application of the selective LAPS inputs played an important role in simulating wind fields accurately in a complex area.

• 한국태양에너지학회 논문집
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• 제34권2호
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• pp.60-65
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• 2014

A meteorological(met) tower is the first structure installed during the planning stages of offshore wind farm. The purpose of this paper is to design the met tower with tripod bucket type support structure and to install the sensors. The support structure consist of a central steel shaft connected to three cylindrical steel suction buckets which is more cheaper than monopile or jacket type. And the remote wind condition sensors and marine monitoring equipment, including adcp, pressure type tide gauge, wave height sensors, and scour sensors, remote power supply are installed. The manufactured met tower constructed on sea area which is in front of Gasa island. All of functions of met tower showed normal operation conditions and the wind data got by remote data collection system successfully.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 International Symposium on Clean Environment
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• pp.51-54
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• 2003

We analyzed radiative properties of aerosols, $CO^{2}$ and clouds using Optical Properties of Aerosols and Clouds(OPAC) and the Column Radiation Model (CRM). From OPAC, if the soot component is disregarded, dust-like components depict the highest extinction values in the solar spectral range and the lowest. single scattering albedoes, which are attributable to the presence of large particles. In the dust aerosol, the high absorptivity in the infrared may induce a warming of the lower atmospheric layer in the nighttime. The radiative properties of aerosols, clouds and double $CO^{2}$ using the CRM model at Seoul (37N, 127.4 E) on 3 April 2003 were calculated. The solar zenith angle is 65˚ and the surface albedo is 0.1836 during the clear day. The aerosol optical depth change 0.14 to 1.7, which is derived during Asian dust days in Korea. At this time, abedo by aerosols is considered as 0.3. In cloudy condition, the short wave cloud forcing on both the TOA and the surface is -193.89 $Wm^{-2}$ and -195.03 $Wm^{-2}$, respectively, and the long wave cloud forcing is 19.58 $Wm^{-2}$ and 62.08 $Wm^{-2}$, respectively. As a result, the net radiative cloud forcing is -174.31 $Wm^{-2}$ and -132.95 $Wm^{-2}$, respectively. We calculate also radiative heating rates by double $CO^{2}$ during the clear day. The $CO^{2}$ volumn mixing ratio is 3.55E-4.

• Asian-Australasian Journal of Animal Sciences
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• 제33권11호
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• pp.1787-1796
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• 2020

Objective: The objective of this study was to determine the digestible energy (DE) and metabolizable energy (ME) of yellow dent corn sourced from different meteorological origins fed to growing pigs and develop equations to predict the DE and ME of yellow dent corn from southwestern China. Methods: Sixty crossbred barrows were allotted to 20 treatments in a triplicate 20×2 incomplete Latin square design with 3 replicated pigs per dietary treatment during 2 consecutive periods. Each period lasted for 12 days, and total feces and urine during the last 5 days of each period were collected to calculate the energy contents. Results: On dry matter (DM) basis, the DE and ME in 20 corn grain samples ranged from 15.38 to 16.78 MJ/kg and from 14.93 to 16.16 MJ/kg, respectively. Selected best-fit prediction equations for DE and ME (MJ/kg DM basis) for yellow dent corn (n = 16) sourced from southwestern China were as follows: DE = 28.58-(0.12×% hemicellulose)+(0.35×% ether extract)-(0.83×MJ/kg gross energy)+(0.20×% crude protein)+(0.49×% ash); ME = 30.42-(0.11×% hemicellulose)+(0.31×% ether extract)-(0.81×MJ/kg gross energy). Conclusion: Our results indicated that the chemical compositions, but not the meteorological conditions or physical characteristics could explain the variation of energy contents in yellow dent corn sourced from southwestern China fed to growing pigs.