• 한국태양에너지학회 논문집
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• 제40권2호
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• pp.37-48
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• 2020

This study compares cloud radiation model (CRM) and sunshine fraction radiation model (SFRM) according to the solar altitude using hourly sunshine duration (SD) and cloud cover (CC) data. Solar irradiance measurements are not easy for the expensive measuring equipment and precise measuring technology. The two models with the site fitting and South Korea coefficients have been analyzed for fourteen cities of South Korea during the period (1986-2015) and evaluated using the root mean square error (RMSE) and the mean bias error (MBE). From the comparison of the results, it is found that the SFRM with the site fitting coefficients could be the best method for fourteen locations. It may be concluded that the SFRM models of South Korea coefficients generated in this study may be used reasonably well for calculating the hourly horizontal global irradiance (HGI) at any other location of South Korea.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.69-74
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• 2008

This study is to analyze and compare on the sky condition of cloud amount and measured solar horizontal irradiation in Seoul. Sky cover method is determination of sky condition used by cloud amount of the Meteorological Administration. And HCI method is determination of sky condition used by measured solar horizontal irradiation. The HCI methods of Erbs et al.(1982), Orgill and Hollands(1977) appear a lot of error because of the air pollution such as smog phenomenon or yellow sand phenomenon and so on. Therefore, The purpose of this study is to improve the method for determination of sky condition.

• 대한원격탐사학회지
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• 제12권1호
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• pp.60-80
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• 1996

AVHRR(Advanced Very High Resolution Radiometer) on NOAA satellite provides data in five spectral, one in visible range, one in near infrared and three in thermal range. In this paper, application of NOAA/AVHRR data is studied for environment monitoring such as cloud top temperature, surface temperature, albedo, sea surface temperature, vegetation index, forest fire, flood, snow cover and so on. The analyses for cloud top temperature, surface temperature, albedo, sea surface temperature, vegetation index and forest fire showed reasonable agreement. But monitoring for flood and snow cover was uneasy due to the limitations such as cloud contamination, low spatial resolution. So this research had only simple purpose to identify well-defined waterbody for dynamic monitoring of flood. Based on development of these basic algorithms, we have a plan to further reseach for environment monitoring using AVHRR data.

• 한국지구과학회지
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• 제38권2호
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• pp.129-140
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• 2017

이 연구에서는 지표 관측 자료와 위성 자료 그리고 GWNU 단층 복사 모델을 이용하여 맑은 상태의 전천 일사량을 계산하였으며, 전운량에 따라 관측 및 모델의 일사량 값을 비교 분석하였다. 연구 자료는 2012년 강릉원주대학교 복사 관측소의 전천 일사량, 기온, 기압, 습도, 에어로졸 등의 관측 자료와 OMI 센서의 오존전량 자료 그리고 구름의 유무 및 전운량을 판단하기 위하여 자동 전운량 장비인 Skyview 자료를 이용하였다. 전운량이 0 할인 맑은 날의 경우 관측 값과 모델 값이 0.98로 높은 상관계수를 나타내었으나 RMSE가 $36.62Wm^{-2}$로 비교적 높게 나타났다. 이는 Skyview 장비가 얇은 구름이나 박무 및 연무 등의 기상상태를 판단하지 못하였기 때문이다. 흐린 날의 경우 구름의 영향을 보정하기 위해 전운량과 두 값의 차에 대한 비율을 이용한 회귀식을 복사 모델에 적용하였으며, 장비의 오탐지를 제외한 경우 상관계수가 0.92로 높은 상관성을 보였으나 RMSE가 $99.50Wm^{-2}$으로 높은 값을 보였다. 더 정확한 분석을 위해서는 직달 성분의 차폐 유무 및 구름 광학 두께를 포함한 다양한 구름 요소의 추가적인 분석이 요구된다. 이 연구결과는 분 또는 시간에 따른 일사량을 산출하여 일사량이 관측되지 않는 지역에서 유용하게 사용될 수 있다.

• 대기
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• 제27권4호
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• pp.499-509
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• 2017

Possible links among cosmic ray, cloud, and climate have scientific uncertainties. The reputed topics have been highly controversial during several decades. A link between the atmospheric ionization by galactic cosmic rays (GCR), which is modulated by solar activities, and global cloud cover was firstly proposed in 1997. Some researchers suggested that the GCR can stimulate the formation of cloud condensation nuclei (CCN) in the atmosphere, and then the higher CCN concentrations may lead to an increase of cloud cover, resulting in a cooling of the Earth's climate, and vise versa. The CLOUD (Cosmic leaving outdoor droplets) experiment was designed to study the effect of GCR on the formation of atmospheric aerosols and clouds under precisely controlled laboratory conditions. A state-of-the-art chamber experiment has greatly advanced our scientific understanding of the aerosol formation in early stage and its nucleation processes if the GCR effect is considered or not. Many studies on the climate-GCR (or space weather) connection including the CLOUD experiment have been carried out during the several decades. Although it may not be easy to clarify the physical connection, the recent scientific approaches such as the laboratory experiments or modeling studies give some implications that the research definitively contributed to reduce the scientific uncertainties of natural and anthropogenic aerosol radiative forcing as well as to better understand the formation processes of fine particulate matters as an important parameter of air quality forecast.

• Design & Manufacturing
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• 제6권1호
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• pp.29-33
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• 2012

A 3D scanner scans and captures the shape of a real-world object. The captured shape can be used to construct three-dimensional model for CAD/CAM applications. In this study we have tried to design a cell phone cover by using the 3D scanner and reverse engineering. A 3D scanner is used to capture the shape of a cell phone. The 3D scanner generates a point cloud as the shape information. A three-dimensional CAD model for the cell phone is constructed from the point cloud. A cell phone cover is designed based on the CAD model of the cell phone. To check the integrity of this design process a prototype of the cover is made and assembled with the cell phone.

• Journal of Biosystems Engineering
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• 제37권1호
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• pp.11-18
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• 2012

Purpose: Short-circuit current of a solar module that is widely used as a power source for wireless environmental sensors is proportional to solar radiation although there are a lot of factors affecting the short-circuit current. The objective of this study is to develop a model for estimating solar radiation for using the solar module as a power source and an irradiance sensor. Methods: An experiment system collected data on the short-circuit current and environmental factors (ambient temperature, cloud cover and solar radiation) during 65 days. Based on these data, two linear regression models and a non-linear regression model were developed and evaluated. Results: The best model was a linear regression model with short-circuit current, angle of incidence and cloud cover and its overall RMSE(Root Means Square Error) was 66.671 $W/m^2$. The other linear model (RMSE 69.038 $W/m^2$) was also acceptable when the cloud cover data is not available.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.232-235
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• 2011

Radiation data are the best source of information for estimating average incident radiation. Lacking this or data from nearby locations of similar climate, it is possible to use empirical relationships to estimate radiation from days of cloudiness. It is necessary to estimate the regression coefficients in order to predict the daily global radiation on a horizontal surface. There fore many different equations have proposed to evaluate them for certain areas. In this work a new correlation has been made to predict the solar radiation for 16 different areas over Korea by estimating the regression coefficients taking into account cloud cover. Particularly, the straight line regression model proposed shows reliable results for estimating the global radiation on a horizontal surface with monthly average deviation of-0.26 to +0.53% and each station annual average deviation of -1.61 to +1.7% from measured values.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.126-129
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• 2012

In this work a new correlation has been made to predict the solar radiation for 16 different areas over Korea by estimating the regression coefficients taking into account cloud hours of bright sunshine. Particularly, the multiple linear regression model proposed shows reliable results for estimating the global radiation on a horizontal surface with monthly average deviation of -0.26 to +0.53% and each station annual average deviation of -1.61 to +1.7% from measured values.

• 대한원격탐사학회지
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• 제25권2호
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• pp.193-203
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• 2009

적설은 지표 에너지수지를 결정하는 중요한 변수중의 하나이다. 위성자료를 이용하여 지면 정보를 산출함에 있어서 적설과 구름을 구분하는 것은 매우 중요한 위성전처리 과정이다. 일반적으로 잘못된 적설과 구름의 분류는 위성자료를 이용한 지면 정보 산출에 있어서 직접적인 오차 요인이 된다. 따라서, 본 연구에서는 원격탐사 자료를 이용하여 적설 지역을 탐지하는 알고리즘에 대해서 연구하고자 한다. 적설역을 탐하지 하기 위해서, 가장 많이 사용되는 정규화 적설 지수(NDSI: Normalized Difference Snow Index)를 사용하지 않고 가시채널과 적외 채널을 이용한 방법을 제시하였다. COMS 기상영상기 (MI: Meteorological Imager) 채널에서는 정규적설 지수 산출 시 요구되는 근적외 채널을 탑재하지 않기 때문이다. 가시 채널을 이용한 적설 탐지는 구름이 혼재되어 있지 않은 지역에서는 잘 탐지하였으나 구름과 혼재되어 있는 지역에서는 어려움이 있다. 이러한 어려움을 보완하기 위해 적외채널 온도차 ($11{\mu}m\;-\;3.7{\mu}m$)를 이용하는 방법을 수행하였다. 온도차를 이용하는 방법은 가시채널만을 적용했을 때 보다는 향상된 탐지 능력을 보인다.