• 천문학회보
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• 제24권2호
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• pp.38-38
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• 1999

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.655-659
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• 2006

Surface Solar Insolation is important for vegetation productivity, hydrology, crop growth, etc. In this study, Surface Solar Insolation is estimated using Multi-functional Transport Satellite (MTSAT-1R) in clear and cloudy conditions. For the Cloudy sky cases, the surface solar insolation is estimated by taking into account the cloud transmittance and multiple scattering between cloud and surface. This model integrated Kawamura's model and SMAC code computes surface solar insolation with a 5km ${\times}$ 5km spatial resolution in hourly basis. The daily value is derived from the available hourly Surface Solar Insolation, independently for every pixel. To validation, this study uses ground truth data recorded from the pyranometer installed by the Korea Meteorological Agency (KMA). The validation of estimated value is performed through a match-up with ground truth. Various match-up with ground truth. Various match-up window sizes are tested with 3${\times}$3, 5${\times}$5, 7${\times}$7, 9${\times}$9, 10${\times}$10, 11${\times}$11, 13${\times}$13 pixels to define the spatial representativity of pyranometer measurement, and to consider drifting clouds from adjacent pixels across the ground station during the averaging interval of 1 hour are taken into account.

• 천문학회지
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• 제47권6호
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• pp.201-207
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• 2014

We report the development of solar flux receivers operating at 2.8 GHz to monitor solar radio activity. Radio waves from the sun are amplified, filtered, and then transmitted to a power meter sensor without frequency down-conversion. To measure solar flux, a calibration scheme is designed with a noise source, an ambient load, and a hot load at $100^{\circ}C$. The receiver is attached to a 1.8 m parabolic antenna in Icheon, owned by National Radio Research Agency, and observation is being conducted during day time on a daily basis. We compare the solar fluxes measured for last seven months with solar fluxes obtained by DRAO in Penticton, Canada, and by the Hiraiso solar observatory in Japan, and finally establish equations to convert observed flux to the so-called Penticton flux with an accuracy better than 3.2 sfu.

• Journal of Astronomy and Space Sciences
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• 제14권2호
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• pp.320-329
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• 1997

전파연구소 이천 분소에는 각각 세 개의 안테나로 30MHz∼2500MHz 대역의 태양전파를 관측할 수 있는 광대 역 태양전파분광시스템이 1995년에 설치되었다. 그 동안 태양전파 데이터를 수집 분석할 수 있는 소프트웨어가 없어 실질적인 관측이 이루어지지 않았으나 본 연구에 의해 운용 소프트웨어가 개발됨으로써 본격적인 태양전파관측 연구를 수행할 수 있게 되었다. 개발된 운용 소프트웨어를 실험 이용한 결과 1997년 11월 4일 06시경(UT)에 연속하여 발생한 3개의 TYPE III Burst에 대한 양질의 관측자료를 얻을 수 있었다. 본 논문에서는 전파연구소 이천 분소의 광대역 전파분광시스템을 소개하고 태양전파 데이터의 취득, 처리 및 분석을 위해 개발한 소프트웨어와 이를 통해 관측된 결과에 대하여 설명한다.

• 대한원격탐사학회지
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• 제22권5호
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• pp.389-396
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• 2006

Surface Solar Insolation is important for vegetation productivity, hydrology, crop growth, etc. In this study, Surface Solar Insolation is estimated using Multi-functional Transport Satellite (MTSAT-1R) in clear and cloudy conditions. For the Cloudy sky cases, the surface solar insolation is estimated by taking into account the cloud transmittance and multiple scattering between cloud and surface. This model integrated Kawamura's model and SMAC code computes surface solar insolation with a $5\;km{\times}5\;km$ spatial resolution in hourly basis. The daily value is derived from the available hourly Surface Solar Insolation, independently for every pixel. To validation, this study uses ground truth data recorded from the pyranometer installed by the Korea Meteorological Agency (KMA). The validation of estimated value is performed through a match-up with ground truth. Various match-up with ground truth. Various match-up window sizes are tested with $3{\times}3,\;5{\times}5,\;7{\times}7,\;9{\times}9,\;10{\times}10,\;11{\times}11,\;13{\times}pixels to define the spatial representativity of pyranometer measurement, and to consider drifting clouds from adjacent pixels across the ground station during the averaging interval of 1 hour are taken into account.

• 천문학회보
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• 제42권2호
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• pp.85.2-85.2
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• 2017

The coronal electron density is a fundamental and important physical quantity in solar physics for estimating coronal magnetic fields and analyzing solar radio bursts. To check a validation of coronal electron density distributions (CEDDs) from polarized brightness (pB) measurements with Van de Hulst inversions, we compare CEDDs derived from a polarized brightness (pB) observation [MLSO/MK4 coronameter] and one spectroscopic observation [SOHO/UVCS]. For this, we consider data observed in 2005 with the following conditions: (1) the observation time differences from each other are less than 1 minutes; and (2) O VI doublet (O VI $1031.9{\AA}$ and $1037.6{\AA}$) is well identified. In the pB observation, the CEDDs can be estimated by using Van de Hulst inversion methods. In the spectroscopic observation, we use the ratio of radiative and collisional components of the O VI doublet to estimate the CEDDs. We find that the CEDDs obtained from pB measurements are higher than those based on UVCS observations at the heights between 1.6 and 1.8 Rs (${\times}1.9$ for coronal streamer, 1.2 ~ 1.8 for background corona, and 1.5 for coronal hole), while they are lower than those based on UVCS at the heights between 1.9 and 2.6 Rs (${\times}0.1{\sim}0.6$ for coronal streamer, 0.5 ~ 0.7 for background corona, and 0.6 for coronal hole). The CEDDs of coronal streamers are higher than those of background corona at the between 1.6 and 2.0 Rs: ${\times}1.2{\sim}2.4$ for MK4 and 1.5 ~ 1.9 for UVCS.

• 태양에너지
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• 제17권2호
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• pp.23-33
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• 1997

This paper reviews the advanced solar cell structures used in space. These are the structures which incorporate the back surface field and reflectors with very shallow and lightly doped emitters. Their use in space has shown that the thinner cells are more resistive to radiation damage than the thicker ones. It has been found that the charged particles affect both the surface and bulk of the cells used in space. This causes degradation in the output power, which in effect, can be explained by the degrading diffusion length of the cells. The PERL cells showed higher BOL(beginning of life) efficiency and almost the same EOL(end of life) efficiency as structures with wrap-around contact configuration fabricated on 10 ${\Omega}cm$ resistivity substrates. This observation lead to a conclusion that, the space cells do not necessarily need to have very high BOL efficiency except in specific missions which require such.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.263-266
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• 2006

Now, on the developing COMS(Communication, Ocean and Meteorological Satellite) has solar panel on the South panel only. Therefore, the wheel off-loading has to be performed periodically to reduce a induced momentum energy by a asymmetric solar panel. One of two East/West station keeping maneuver to correct simultaneously longitude and eccentricity, orbit corrections may be performed during one of the two wheel off-loading manoeuvres per day to get enough observation time for meteorological and ocean sensor. In this paper, we applied a linearized orbit maneuver equation to acquire maneuver time and delta-V. Nonlinear simulation for the station keeping is performed and compared with general station keeping strategy for fuel reduction.

• 천문학회지
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• 제29권spc1호
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• pp.391-392
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• 1996

We have developed and tested a CCD camera (100 $\times$ 100 pixels) system for observing Ha images of the solar flares with time resolution> 25 msec. The 512 $\times$ 512 pixels image of CCD camera at 2 Mpixels/sec can be recorded at the rate of more than 5 frame/sec while 100 $\times$ 100 pixels area image can be obtained 40 frames/sec. The 100 $\times$ 100 pixels image of CCD camera corresponds to 130 $\times$ 130 arc - $sec^2$ of the solar disk.

• 천문학회지
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• 제47권6호
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• pp.311-317
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• 2014

Solar chromospheric surges are often reported to contain rotational motion. However, the details of the motion and driving mechanism of the surges are not yet fully understood. Recurrent surges with rotational motion at AR 10930 on the west limb are observed by Hinode Solar Optical Telescope (SOT) continuously from 11:21 UT on December 18 to 09:58 UT on December 19, 2006, using the $Ca_{II}$ H broadband filter. We analyze details of the motion including number of turns from the rise of the surge to the fall, axial speed and acceleration. During the observation, rise and fall motion accompanying rotation appears recurrently. There occur a total of 14 surges at AR 10930 over 17 hours. The average duration is 45 minutes, and the average width, and length are 8 Mm, and 39 Mm, respectively. We speculate that the surges occurred by recurrent reconnections between the twisted prominence and large untwisted flux tube.