Interannual variability of the 12-hour tide in the mesosphere and lower thermosphere in 15 years of meteor-radar observations above Rothera (68°S, 68°W)
Interannual variability of the 12-hour tide in the mesosphere and lower thermosphere in 15 years of meteor-radar observations above Rothera (68°S, 68°W)
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罗瑟拉上空 15 年流星雷达观测中中层和低热层 12 小时潮汐的年际变化（68
DOI：
10.1002/essoar.10510647.1
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Dempsey S
中科院分区：
文献类型：
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作者：
Dempsey S
中间层和低热层太阳潮汐在日到年的时间尺度上表现出很大的变异性，在年际尺度上表现出显著的变异性。然而，这种变异性的性质和原因仍然知之甚少。在这里，我们提供了2005-2020年期间用流星雷达在罗瑟拉(68°S，68°W)上空测量的12小时潮汐年际变化的测量结果。我们使用线性回归分析研究了12小时潮汐振幅与几个气候指标的相关性，特别是太阳周期(由F10.7太阳通量测量)、厄尔尼诺南方涛动(ENSO)、10和30 GHz的准两年振荡(QBO)和南环模(SAM)。我们的观测表明，12小时的潮汐幅度大，有明确的季节周期，月平均值高达35米，S−1。我们观察到很大的年际变化，在95公里处的月平均12小时潮汐振幅表现出两个标准差范围(2σ)，春季：S−1 13.4m，夏季11.2m，S−1，秋季18.6m，S−1，冬季7.0m。我们发现，F10.7、QBO10、QBO30和SAM与12小时潮汐振幅在95%的水平上都有显著的相关性，并呈现出线性趋势。而我们发现与ENSO的相关性很小。这些结果表明，F10.7、QBO和SAM的变化可能是南极MLT 12小时潮汐振幅年际变化的重要原因。
The solar tides of the mesosphere and lower thermosphere (MLT) show great variability on time scales of days to years, with significant variability at interannual time scales. However, the nature and causes of this variability remain poorly understood. Here, we present measurements made over the interval 2005–2020 of the interannual variability of the 12‐hr tide as measured at heights of 80–100 km by a meteor radar over Rothera (68°S, 68°W). We use a linear regression analysis to investigate correlations between the 12‐hr tidal amplitudes and several climate indices, specifically the solar cycle (as measured by F10.7 solar flux), El Niño Southern Oscillation (ENSO), the Quasi‐Biennial Oscillation (QBO) at 10 and 30 hPa and the Southern Annular Mode (SAM). Our observations reveal that the 12‐hr tide has a large amplitude and a clearly defined seasonal cycle with monthly mean values as large as 35 m s−1. We observe substantial interannual variability, with monthly mean 12‐hr tidal amplitudes at 95 km exhibiting a two standard‐deviation range (2σ) in spring of 13.4 m s−1, 11.2 m s−1in summer, 18.6 m s−1in autumn, and 7.0 m s−1in winter. We find that F10.7, QBO10, QBO30, and SAM all have significant correlations to the 12‐hr tidal amplitudes at the 95% level, with a linear trend also present. Whereas we detect very minimal correlation with ENSO. These results suggest that variations in F10.7, the QBO and SAM may contribute significantly to the interannual variability of 12‐hr tidal amplitudes in the Antarctic MLT.