• Journal of the Korean earth science society
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• v.33 no.7
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• pp.608-617
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• 2012

The symbiotic nova Z Andromedae (And) was investigated, using the high dispersion spectra of spectral resolution, ${\Delta}{\lambda}{\sim}-0.1{\AA}$. The spectral observations were done with (1) the Hamilton Echelle Spectrograph (HES) and the high resolution spectra (exposures=1800s and 3600s) were obtained at Lick Observatory in 2001 August $30^{th}$ (phase ${\Phi}$=0.77), and 2002 August $12^{th}$ (phase ${\Phi}$=0.22), (2) with the Bohyunsan Echelle Spectrograph (BOES) at Bohyunsan Optical Astronomy Observatory and the high resolution spectra (exposure=1200s) were secured in 2009 October $21^{st}$ (phase ${\Phi}$=0.70). From both the HES and BOES spectral data in the $3600{\AA}-9500{\AA}$ wavelengths, we extracted the emission lines of HI, HeI, and HeII, which have been decomposed into double or triple Gaussian components for 3 consecutive phases. The emission zones responsible for these components appear to be closely related with the orbital motion of a white dwarf or a giant star. The presence of the Raman scattering $H{\alpha}$ broad wing feature and the kinematic characteristics of the line profile observed in each phase imply that the Z And emission lines are mostly from two Lagrangian points, $L_1$ and $L_2$, and the accretion disk around the white dwarf star. The Z And was most active in 2009 and 2001 during the outburst phase, while it remained quiescent in 2002 in spite of the complex line profiles.

• Journal of the Korean earth science society
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• v.33 no.7
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• pp.596-607
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• 2012

The R-Z relationship is one of important error factors to determine the accuracy of radar rainfall estimation. In this study, we have explored the effect of the R-Z relationships derived from disdrometer data in estimating the radar rainfall. The heavy rain event that produced flooding in St-Remi, Quebec, Canada has been occurred. We have tried to investigate the severity of rain for this event using high temporal (2.5 min) and spatial resolution ($1^{\circ}$ by 250 m) radar data obtained from the McGill S-band radar. Radar data revealed that the heavy rain cells pass directly over St-Remi while the coarse raingauge network was not sufficient to detect this rain event. The maximum 30 min (1 h) accumulation reaches about 39 (42) mm in St-Remi. During the rain event, the two disdrometers (POSS; Precipitation Occurrence Sensor System) were available: One used for the reflectivity calibration by comparing disdrometer Z and radar Z and the other for deriving disdrometric R-Z relationships. The result shows the significant improvement with the disdrometric reflectivity-dependent R-Z relationships against the climatological R-Z relationship. The bias in radar rain estimation is reduced from +12% to -2% and the root-mean squared error from 16 to 10% for daily accumulation. Using the estimated radar rainfall rate with disdrometric R-Z relationships, the flood event was well captured with proper timing and amount.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.828-834
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• 2013

In this paper, TMC (Tracker Motion Controller) as one of the many research methods for condensing efficiency improvements can be condensed into efficient solar system configuration to improve the power generation efficiency of the castle with Concentrated solar silicon and photovoltaic systems (CPV)experiments using PV systems. Microprocessor used on the solar system, tracing the development of solar altitude and latitude of each is calculated in real time. Also accept the value from the sensor, motor control and communication with the central control system by calculating the value of the current position of the sun, there is a growing burden on the applicability. Through the way the program is appropriate for solar power systems and sensors hybrid-type algorithm was implemented in the ARM core with built-in TMC, Concentrated CPV system compared to the existing PV systems, through the implementation of the TMC in the country's power generation efficiency compared and analyzed. Sensor method using existing experimental results Concentrated solar power systems to communicate the value of GPS location tracking method hybrid solar horizons in the coordinate system of the sun's azimuth and elevation angles calculated by the program in the calculations of astronomy through experimental resultslook clear day at high solar irradiation were shown to have a large difference. Stopped after a certain period of time, the sun appears in the blind spot of the sensor, the sensor error that can occur from climate change, however, do not have a cloudy and clear day solar radiation sensor does not keep track of the position of the sun, rather than the sensor of excellence could be found. It is expected that research is constantly needed for the system with ongoing research for development of solar cell efficiency increases to reduce the production cost of power generation, high efficiency condensing type according to the change of climate with the optimal development of the ability TMC.

• Atmosphere
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• v.19 no.3
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• pp.237-242
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• 2009

The first domestic expert workshop on surface flux measurement and modeling was held on 10-12 June 2009 in Seoul to invigorate research cooperation on soil-vegetation-atmosphere interactions in Korea and to promote interdisciplinary studies. This article provides a summary of the workshop presentations and recommendations, and future research directions for surface processes in Korea.

• Atmosphere
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• v.22 no.1
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• pp.97-107
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• 2012

To investigate variation of aerosol number concentration at each different size with three-dimensional (3D) wind components in ocean area, aerosol particles and 3D wind components were measured in the Ieodo Ocean Research Station, which is located to 419 km southwest from Marado, the southernmost island of Korea, from 25 June to 8 July 2010. The Laser Particle Counter (LPC) and ultrasonic anemometer were used to measure the size of aerosol particles and 3D wind components (zonal (u), meridional (v), and vertical (w) wind) respectively. Surface weather chart, NCEP/NCAR reanalysis data and sounding data were used to analyze the synoptic condition. The distribution of aerosol number concentration had a large variation from bigger particles more than 1.0 ${\mu}m$ in diameter by wind direction during precipitation. In the number concentration of aerosol particles with respect to the weather conditions, particles larger than 1.0 ${\mu}m$ in size were decreased and sustained to the similar concentration at smaller particles during precipitation. The increase in aerosol number concentration was due to the sea-salt particles which was suspended by southwesterly and upward winds. In addition, the aerosol number concentration with vertical wind flow could be related with the occurrence and increasing mechanism of aerosol in marine boundary layer.

• Journal of Astronomy and Space Sciences
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• v.15 no.2
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• pp.401-415
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• 1998

This paper reports the results obtained from the Langmuir probe (LP) and Electron Temperature Probe (ETP) experiments on the sounding rocket KSR-II (Korean Scientific Rocket - II) which was launched on Jun 11, 1998 at 10:00 KST from Tae-An peninsula (37$^{\circ}$ N, 126$^{\circ}$ E). The instruments successfully measured the electron density, electron temperature, and the floating potential at altitudes of 73km to 130km. While the electron temperature measurement is not easy in this region, since the temperature is very low and the contamination effect of the probe may give rise to a problem, we were able to obtain a reasonable electron temperature profile by employing two independent methods, the pulse modulated Langmuir Probe and Electron Temperature Probe. The preliminary results show that electron density increases sharply at about 90km, and forms a peak at 102km. The density profile is roughly consistent with IRI (International Reference Ionosphere)95-model or PIM (Parameterized Ionospheric Model) results except that the peak density appears at 110km in the model and model electron density is slightly lower than the observed one. Electron temperature obtained from ETP fluctuates between 200$^{\circ}$K and 700$^{\circ}$K, an effect presumably coming from the wakes developed by LP, and it tends to increase with the altitude, which is consistent with the LP results.

• Journal of Astronomy and Space Sciences
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• v.28 no.2
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• pp.123-132
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• 2011

It is generally believed that the occurrence of a magnetic storm depends upon the solar wind conditions, particularly the southward interplanetary magnetic field (IMF) component. To understand the relationship between solar wind parameters and magnetic storms, variations in magnetic field polarity and solar wind parameters during magnetic storms are examined. A total of 156 storms during the period of 1997~2003 are used. According to the interplanetary driver, magnetic storms are divided into three types, which are coronal mass ejection (CME)-driven storms, co-rotating interaction region (CIR)-driven storms, and complicated type storms. Complicated types were not included in this study. For this purpose, the manner in which the direction change of IMF $B_y$ and $B_z$ components (in geocentric solar magnetospheric coordinate system coordinate) during the main phase is related with the development of the storm is examined. The time-integrated solar wind parameters are compared with the time-integrated disturbance storm time (Dst) index during the main phase of each magnetic storm. The time lag with the storm size is also investigated. Some results are worth noting: CME-driven storms, under steady conditions of $B_z$ < 0, represent more than half of the storms in number. That is, it is found that the average number of storms for negative sign of IMF $B_z$ (T1~T4) is high, at 56.4%, 53.0%, and 63.7% in each storm category, respectively. However, for the CIR-driven storms, the percentage of moderate storms is only 29.2%, while the number of intense storms is more than half (60.0%) under the $B_z$ < 0 condition. It is found that the correlation is highest between the time-integrated IMF $B_z$ and the time-integrated Dst index for the CME-driven storms. On the other hand, for the CIR-driven storms, a high correlation is found, with the correlation coefficient being 0.93, between time-integrated Dst index and time-integrated solar wind speed, while a low correlation, 0.51, is found between timeintegrated $B_z$ and time-integrated Dst index. The relationship between storm size and time lag in terms of hours from $B_z$ minimum to Dst minimum values is investigated. For the CME-driven storms, time lag of 26% of moderate storms is one hour, whereas time lag of 33% of moderate storms is two hours for the CIR-driven storms. The average values of solar wind parameters for the CME and CIR-driven storms are also examined. The average values of ${\mid}Dst_{min}{\mid}$ and ${\mid}B_{zmin}{\mid}$ for the CME-driven storms are higher than those of CIR-driven storms, while the average value of temperature is lower.

• Journal of Astronomy and Space Sciences
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• v.22 no.2
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• pp.113-124
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• 2005

All times of minimum light for two eclipsing binaries V343 Aql and CX Aqr were collected and analyzed to study their orbital period variations. It was found that the orbital periods for both stars have varied in a cyclical way superposed on a parabola. A secular period decrease of $-261{\times}10^{-7}$ d/y for V343 Aql was calculated while CX Aqr showed a secular period increase of $+2.55{\times}10^{-8}$8 d/y. Possible causes of secular period variations for two systems were discussed. The cyclical period variation was interpreted as light-time effect due to a third body. The resultant period, semiamplitude and eccentricity of the light time orbit were calculated to be 30.3y, 0.0092d and 0.85, respectively, for V343 Aql and 33.0y, 0.0037d and 0.64, respectively, for CX Aqr. The properties of the third bodies suggested in V343 Aql and CX Aqr systems were discussed.

• Journal of Astronomy and Space Sciences
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• v.15 no.1
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• pp.119-138
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• 1998

Recently measurements of atmospheric trace gases from satellite are vigorous. So the development of its data processing algorithm is important. In this study, retrievalof vertical ozone profile from the atmospheric transmittance measured by satellite solar occultation method and its sensitivity to temperature and pressure are investigated. The measured transmittance from satellite is assumed to be given by the limb path transmittance simulated using annual averaged Umkehr data for Seoul. The limb path transmittance between wavelengths $9.89{\mu}m$ and $10.2{\mu}m$ is simulated with respect to tangent heights using the ozone data of HALOE SIDS(Hallogen Occultation Experiment Simulated Instrument Data Set) as an initial profile. Other input data such as pressure and temperature are also from HALOE SIDS. Vertical ozone profile is correctly retrieved from the measured transmittance by onion-peeling method from 50km to 11km tangent heights with the vertical resolution of 3km. The bias error of $\pm0.001$ in measured transmittance, the forced error of $\pm3K$ in each layer temperature, and the forced $\pm3%$ error in each layer pressure are assumed for sensitivity tests. These errors are based on the ADEOS/ILAS error limitation. The error in ozone amount ranges from -6.5% to +6.9% due to transmittance error, from -9.5% to +10.5% due to temperature error, and from -5.1% to +5.4% due to pressure error, respectively. The present study suggests that accurate vertical ozone profile can be retrieved from satellite solar occultation method. Accuracy of vertical temperature profile is especially important in the retrieval of vertical ozone profile.

• Journal of Astronomy and Space Sciences
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• v.12 no.1
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• pp.21-29
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• 1995

The $\beta$ Lyrae-type eclipsing binary AW Cam was observed photoelectrically in three wavelength regions. The obtained UBV light curves of AW Cam were analyzed with two separate modes(mode 2 for detached systems and mode 5 for semi-detached ones) of the Wilson-Devinney binary mode. It is intended to resolve the discrepancy in AW Cam system that the photometrio mass ratio (q=0.21) derived by Russo and Milano (1983) is not consistent with the spectroscopic result (q=0.43) by Mammano et al.(1967). Our photomtric solutions derived with mode 2 are fitted better to the observed light curves than those of mode 5, supporting that AW Cam may be not a normal semi-detached system but a detached one. Three dimensional Roche configuration of AW Cam system calculated with the derived mass ratio (q=0.43) reveals that the less massive secondary with the confined within its inner Roche lobe, while the more massive rimary is in marginally contact. From the Roche geometry, the constancy of the orbital period and other photometric evidences of AW Cam, it is provisionally concluded that the system is an unevolved detached binary in is provisionally concluded that the system is an unevolved detached binary in the phase of case A evolution toward 'contact phase' rather than and evolved one in 'broken-contact phase' suggested by Giuricin and Mardrossian (1981).