Observations of evolution-type band-like structures of F region irregularities
Observations of evolution-type band-like structures of F region irregularities
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F区不规则演化型带状结构的观测
DOI：
10.1029/2018ja026091
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Sicheng Wang
中科院分区：
文献类型：
--
作者：
Xing Meng;Hanxian Fang;Guozhu Li;Libin Weng;Sicheng Wang
通常，赤道扩展-F（ESF）不规则性始于电离层F区域的底部，并在RTI（距离-时间-强度）图中表现为高度范围超过50 km的羽流结构。利用位于中国低纬的福科和三亚甚高频雷达，观测到了近局地日落时ESF不规则体的演化型带状结构。一个有趣的方面是，ESF带状结构最初出现在400公里以上的高空，然后上升到更高的高度，没有纬向传播。这些ESF带状结构的寿命小于25分钟，在每个雷达波束的RTI图中具有相似的图案。观察到F区不规则结构的带状结构，具有大的多普勒速度和窄的频谱宽度。在ESF带状结构存在期间，检测到表观振幅波动（S4 > 0.2），总电子含量（TEC）快速波动（ROTI > 1）和范围型扩展F。可能的机制负责的初始生成带状ESF不规则性在高海拔地区进行了讨论。
Generally, equatorial spread‐F(ESF) irregularities initiated at the bottom of the ionosphericFregion and manifested as plume structures with an altitude extent more than 50 km in the RTI (range‐time‐intensity) plot. By using the Fuke and Sanya VHF radars located at low latitude of China, evolution‐type band‐like structures of ESF irregularities were observed near local sunset. One interesting aspect is that the ESF band‐like structures initially appeared at high altitudes more than 400 km and then uplifted to higher altitude without zonal propagation. The lifetime of these ESF band‐like structures, with a similar pattern in the RTI plot for each beam of radar, is less than 25 min. The band‐like structures ofFregion irregularities were observed with big Doppler velocities and narrow spectral widths. During the presence of ESF band‐like structures, apparent amplitude scintillations (S4 > 0.2), total electron content (TEC) fast fluctuations (ROTI > 1), and range‐type spreadFwere detected. Possible mechanisms responsible for the initial generation of band‐like ESF irregularities at high altitude are discussed.