First observation of presunset ionospheric F region bottom-type scattering layer
First observation of presunset ionospheric F region bottom-type scattering layer
复制标题
DOI：
10.1002/2016ja023647
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Chunxiao Yan
中科院分区：
文献类型：
--
作者：
Guozhu Li;Baiqi Ning;M.A. Abdu;Weixing Wan;Chi Wang;Guotao Yang;Kangkang Liu;Libo Liu;Chunxiao Yan
The bottom-type irregularity scattering layer (BSL) that can appear in the ionospheric F region.bottomside has been observed generally after sunset, serving as a possible telltale of equatorial spread F.(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 the F layer 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 of F region plasma density.large-scale wave structure before sunset. These observations could imply an important role of gravity waves.in the generation of the presunset F region bottom-type irregularities.
