Radar and Satellite Investigations of Equatorial Evening Vertical Drifts and Spread F
Radar and Satellite Investigations of Equatorial Evening Vertical Drifts and Spread F
复制标题
赤道夜间垂直漂移和传播 F 的雷达和卫星调查
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
E. Paula
中科院分区：
文献类型：
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作者：
J. M. Smith;F. Rodrigues;E. Paula
摘要。本文分析了2010年8月至2012年2月巴西圣路易斯30 MHz相干后向散射雷达在赤道F区午夜前的观测数据。这些测量数据经过处理后，用于绘制回声发生随当地时间和高度变化的月度地图。这些地图显示了巴西经度扇区赤道传播F （ESF）发生的年际变化。我们还利用C/NOFS卫星上的离子速度计（IVM）的测量结果，为巴西区域构建了夜间垂直漂移的月曲线。IVM的夜间漂移与Scherliess和Fejer（1999）的经验模型总体上一致。在ESF季节，实测漂移和模式漂移显示了垂直等离子体漂移的预反转增强（PRE -reversal enhancement， PRE）的发展。通过雷达和卫星联合测量，我们发现傍晚（18:00-18:30 LT）平均非负漂移为上层ESF回波的发生提供了必要条件，但不是充分条件。夜间向下（负）漂移先于上层ESF不规则现象的消失。
Abstract. We analyzed pre-midnight equatorial F region observations made by the 30 MHz coherent backscatter radar of Sao Luis, Brazil between August 2010 and February 2012. These measurements were processed, and used to create monthly maps of the echo occurrence as a function of local time and height. The maps show the inter-annual variability associated with equatorial spread F (ESF) occurrence in the Brazilian longitude sector. We also constructed monthly curves of the evening vertical drifts, for the Brazilian sector, using measurements by the ion velocity meter (IVM) onboard the C/NOFS satellite. The IVM evening drifts show a good overall agreement with the Scherliess and Fejer (1999) empirical model. Measured and model drifts show the development of the pre-reversal enhancement (PRE) of the vertical plasma drifts during ESF season. Using joint radar and satellite measurements, we found that evening (18:00–18:30 LT) mean non-negative drifts provide a necessary but not sufficient condition for the occurrence of topside ESF echoes. Evening downward (negative) drifts preceded the absence of topside ESF irregularities.