First observation of presunset ionospheric F region bottom-type scattering layer
First observation of presunset ionospheric F region bottom-type scattering layer
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首次观测到日落前电离层F区底部型散射层
DOI：
10.1002/2016ja023647
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发表时间：
2017
影响因子：
2.8
通讯作者：
Yan Chunxiao
中科院分区：
文献类型：
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作者：
Li Guozhu;Ning Baiqi;Abdu M. A.;Wan Weixing;Wang Chi;Yang Guotao;Liu Kangkang;Liu Libo;Yan Chunxiao
通常在日落后观测到电离层F区域底部出现的底部型不规则散射层（BSL），它可能是赤道扩展F（ESF）的信号。利用多波束雷达同时测量三亚两个低纬度站，（18.3°N，109.6°E;倾角纬度13°N）和福科（19.3°N，109.1°E;在中国北纬14°附近，我们首次报道了一个薄的BSL，它最初发生在日落前（~1720 LT），比赤道等离子体剪切涡驱动的不稳定性产生的BSL的发生早得多。日落前的BSL位于225 km的高度，并持续存在，直到日落后（~1930 LT）ESF羽状物的出现。有趣的是，日落前三亚地区BSL回波的多普勒速度和同期数字探空仪测量的Flayer虚高都显示出约1 h的振荡，表明日落前BSL和Flayer区等离子体密度大尺度波结构的出现有密切的联系。这些观测结果可能意味着重力波在产生presunsetF区域底型不规则性中的重要作用。
The bottom‐type irregularity scattering layer (BSL) that can appear in the ionosphericFregion bottomside has been observed generally after sunset, serving as a possible telltale of equatorial spreadF(ESF). Using simultaneous multibeam radar measurements over two low‐latitude stations, Sanya (18.3°N, 109.6°E; dip latitude 13°N) and Fuke (19.3°N, 109.1°E; dip latitude 14°N) in China, we report, for the first time, a thin BSL that initially occurred at presunset (~1720 LT), much earlier than the occurrence of BSL generated from the equatorial plasma shear vortex‐driven instability. The presunset BSL was situated around 225 km altitude and continued to exist until the appearance of ESF plumes after sunset (~1930 LT). Interestingly, the Doppler velocities of the presunset BSL echoes measured by the radar and theFlayer virtual heights obtained from the collocated Digisonde measurements over Sanya both show oscillations with a period of about 1 h, suggesting a close link between the occurrences of the BSL and ofFregion plasma density large‐scale wave structure before sunset. These observations could imply an important role of gravity waves in the generation of the presunsetFregion bottom‐type irregularities.