• Title/Summary/Keyword: superrefraction

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A Study on Abnormal Echoes in a Meteorological Radar (기상레이더에서의 이상에코에 관한 연구)

  • 허택산;강봉수;김흥수
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.41 no.8
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    • pp.131-137
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    • 2004
  • The aim of this paper is to find the weather conditions which make the abnormal propagation of a radar bear In order to analyze the weather conditions which cause superrefraction or ducting, the meteorological data of the west sea and the south sea of Korea are classified which are observed during three years from 2000. Atmospheric indexes of refraction with increasing altitude are calculated and the rate of variation of temperature and hmidity at the altitude where the index is very low are observed. It is found that unwanted radar echoes by anomalous propagation are showed up only when the atmospheric indexes of refraction at a altitude is less than -150/km and the reverse layer of temperature appears with a sudden drop of humidity at the altitude.

Statistical Characteristics of Atmospheric Conditions related to Radar Beam Propagation using Radiosonde Data in 2005-2006 (2005-2006년 라디오존데 자료를 이용한 레이더 빔전파와 연관된 대기상태의 통계적 특성)

  • Jung, Sung-Hwa;Lee, Gyu-Won
    • Journal of the Korean earth science society
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    • v.31 no.6
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    • pp.584-599
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    • 2010
  • The variation of atmospheric conditions including subrefraction, normal refraction, superrefraction, and ducting is an important factor that affects the quality of radar data by controling the propagation of radar beams. The occurrence frequency of the conditions is statistically analyzed using the atmospheric soundings from seven radiosonde stations in South Korea over two years. The occurrence of superrefraction and ducting at Baengnyeongdo is significantly higher than the others. Osan and Kwangju show significant variation in time. Among the different duct conditions, the surface duct is dominant at most stations except for Gosan. The elevated duct is dominant at Heuksando and Gosan. Duct is more frequent in summer than in winter at all stations. Baengnyeongdo shows the most frequent duct in spring, fall, and winter while Pohang had the highest frequency in summer. Osan and Kwangju show least duct during all seasons. The difference of variation of monthly duct occurrence between 00 UTC and 12 UTC is insignificant at all stations except for Osan and Kwangju. Kwangju, Heuksando and Gosan show relatively low frequency of duct with the monthly maximum barely reaching 60%. The highest number of elevation angles that are affected by duct was four at Osungsan radar (KSN). The maximum elevation angle is around $1.0^{\circ}$ at all stations and Jindo radar (JNI) shows the maximum value of $1.2^{\circ}$.