Finland HF and Esrange MST radar observations of polar mesosphere summer echoes
Finland HF and Esrange MST radar observations of polar mesosphere summer echoes
复制标题
芬兰 HF 和 Esrange MST 雷达观测极地中间层夏季回波
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
M. Lester
中科院分区：
文献类型：
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作者：
T. Ogawa;N. Arnold;S. Kirkwood;N. Nishitani;M. Lester
抽象。本文介绍了芬兰SuperDARN高频雷达在夏季观测到的特殊近距离回波。在105-250 km斜距上，在9、11、13和15 MHz四个频率上探测了约100 min的回波。干涉仪测量表明，回波来自80-100 km高度，仰角为20°-60°。回波功率（16分贝），多普勒速度（-30和+30毫秒-1）和频谱宽度（60毫秒-1）波动的周期为几到20分钟，可能是由于短周期的大气重力波。当高频雷达探测到回波时，位于瑞典Esrange（高频雷达站以北650公里）的垂直入射MST雷达在80-90公里高度观测到极地中层夏季回波。这一事实表明，近距离高频回波是PMSE在高频波段，虽然两个雷达没有探测到一个共同的体积。随着雷达频率的增加，高频回波距离雷达站越来越近，回波功率逐渐减弱。可能的机制来解释这些功能进行了讨论。关键词。气象学和大气动力学（中层大气动力学;热层动力学;波浪和潮汐;仪器和技术）
Abstract. Peculiar near range echoes observed in summer with the SuperDARN HF radar in Finland are presented. The echoes were detected at four frequencies of 9, 11, 13 and 15 MHz at slant ranges of 105–250 km for about 100 min. Interferometer measurements indicate that the echoes are returned from 80–100 km altitudes with elevation angles of 20°–60°. Echo power ( 16 dB), Doppler velocity (between –30 and + 30 ms-1) and spectral width ( 60 ms-1) fluctuate with periods of several to 20 min, perhaps due to short–period atmospheric gravity waves. When the HF radar detected the echoes, a vertical incidence MST radar, located at Esrange in Sweden (650 km north of the HF radar site), observed polar mesosphere summer echoes (PMSE) at altitudes of 80–90 km. This fact suggests that the near range HF echoes are PMSE at HF band, although both radars did not probe a common volume. With increasing radar frequency, HF echo ranges are closer to the radar site and echo power becomes weaker. Possible mechanisms to explain these features are discussed. Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; thermospheric dynamics; waves and tides; instruments and techniques)