Spread F occurrence and drift under the crest of the equatorial ionization anomaly from continuous Doppler sounding and FORMOSAT-3/COSMIC scintillation data

Jaroslav Chum, Jann Yenq Liu, Shih Ping Chen, Miguel Angel Cabrera, Jan Laštovička, Jiří Baše, Dalia Burešová, Jiří Fišer, František Hruška, Rodolfo Ezquer

研究成果: Article同行評審

7 引文 斯高帕斯(Scopus)

摘要

A relatively new method based on measurements by multipoint continuous Doppler sounding is applied to study the occurrence rate, propagation velocities, and directions of spread F structures over Tucumán, Northern Argentina, and Taiwan, both of which were under the crest of the equatorial ionization anomaly in 2014. In addition, spread F is studied globally over the same time period from the S4 scintillation index measured onboard FORMOSAT-3/COSMIC (F3/C) satellite. It is shown that the continuous Doppler sounding gives results that are consistent with S4 data and with previous optical, global positioning system (GPS), and satellite measurements. Most of the spread F events were observed from September to March, i.e., during the local summer half of the year in Tucumán, whereas in Taiwan, the highest occurrence rate was observed around equinoxes. The occurrence rate in Tucumán was about four times higher than that in Taiwan. The propagation velocities and directions were estimated from the Doppler shift spectrograms. The spread structures related to spread F propagated roughly eastward at velocities from ~70 to ~200 m s-1 during nighttime hours. The mean observed horizontal velocity was 140 m s-1 over Tucumán and 107 m s-1 over Taiwan. The local times at which the highest velocities were observed roughly correspond to local times with highest values of scintillation index S4, at ~20 to 23 LT. In addition, a comparison of measured drift velocities with neutral wind velocities predicted by models is provided. The observed velocities usually exceeded the horizontal neutral wind velocities predicted by the HWM14 model for the locations and times of observations.

原文English
文章編號56
期刊Earth, Planets and Space
68
發行號1
DOIs
出版狀態Published - 2016 十二月 1

All Science Journal Classification (ASJC) codes

  • 地質學
  • 空間與行星科學

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