Digital measurements of LF radio wave absorption in the lower ionosphere and inferred gravity wave activity
Digital measurements of LF radio wave absorption in the lower ionosphere and inferred gravity wave activity
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低电离层低频无线电波吸收的数字测量和推断的重力波活动
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
D. Burešová
中科院分区：
文献类型：
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作者：
J. Laštovička;J. Boška;D. Burešová
自1957年以来，一直在Praghonice（北纬50度）测量低电离层中的低频无线电波吸收。1988年引进了一种新的数字计算机控制的测量-记录-处理系统。简要介绍了用于270 kHz数字测量的测量设备A3法或无线电波吸收测量。数字化夜间低频A3测量允许使用吸收数据来研究和监测10 min-3（2）h周期范围内中上层大气的重力波活动。由此产生的重力波谱与预期的一样，尽管它们的形状不同。个别周期带有时表现出类似的一般模式的变化，在重力波活动（1990年冬季），而在其他时间间隔，我们观察到的重力波能量从一个周期带转移到另一个（1991年冬季）。没有强烈的，明显的和一致的反应，强烈的磁暴和隆冬平流层warmings.A明显的季节变化与冬季最小值观察到的较短周期的重力波活动是一个人为的变化长度的夜晚。分析数据中重力波活动没有显着的季节变化。这种方法非常便宜--结果是为电离层目的进行测量的副产品
Low frequency (LF) radio wave absorption in the lower ionosphere has been measured at Průhonice (∼ 50°N) since 1957. A new digital computer-controlled measuring-recording-processing system was introduced in 1988. The A3 method or radio wave absorption measurement, the measuring equipment used for the digital measurements at 270 kHz, is briefly described. The digital nighttime LF A3 measurements allow the use of absorption data for studying and monitoring the gravity wave activity in the upper middle atmosphere in the period range 10 min-3 (2) hours. The resulting gravity wave spectra are as expected even though their shapes vary. Individual period bands sometimes exhibit a similar general pattern of variability in gravity wave activity (winter 1990), while in other intervals we observe a shift of gravity wave energy from one period band to another (winter 1991). No strong, pronounced and consistent response to strong geomagnetic storms and midwinter stratospheric warming is found. An apparent seasonal variation with winter minima observed in shorter-period gravity wave activity is an artefact of the changing length of the night. There is no significant seasonal variation of gravity wave activity in the analysed data. The method is very cheap - the results are a by-product of measurements made for ionospheric purposes