TY - JOUR
T1 - Solar Dependence of Equatorial F Region Irregularities Observed by COSMIC Radio Occultations
AU - Yu, Tao
AU - Miyoshi, Yasunobu
AU - Xia, Chunliang
AU - Zuo, Xiaomin
AU - Yan, Xiangxiang
AU - Yang, Na
AU - Sun, Yangyi
AU - Yue, Xinan
AU - Mao, Tian
N1 - Funding Information:
We thank the CDAAC team for selfless delivery of COSMIC RO data. This work was supported by the Strategic Priority Research Program of Chinese Academy of Sciences (grant XDA17010207), and the National Natural Science Foundation of China (grants 41574147 and 41774164). This work was partly supported by International Exchange Program of National Institute of Information and Communications (NICT).
Publisher Copyright:
© 2018. American Geophysical Union. All Rights Reserved.
PY - 2018/11
Y1 - 2018/11
N2 - With an improved method for retrieving the equatorial F region irregularities (EFIs) from radio occultation measurements, a huge amount of S4 index profiles from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites is employed to study the solar cycle variation of global EFIs during the period of 2007 to 2017. This full solar cycle data show that impacts of the solar activity on the occurrence rates and heights of EFIs are notable and complex. The occurrence rates of EFIs at higher altitude (greater than 500 km) increase with increasing the solar activity. The mean heights ((Formula presented.)) and heights standard deviation (σh) of EFIs at higher altitudes do not show clearly the solar activity dependence. On the other hand, the occurrence rates of EFIs at entire altitudes (from 150 to 800 km) do not have clear relation with the solar activity. The (Formula presented.) and σh of EFIs at entire altitudes increase with increasing the solar activity. Moreover, the dependence of the occurrence rates of EFIs on the solar activity are the strongest in the equinoxes, weaker in winter and weakest in summer. The electric fields and corresponding seasonal variation can account for the EFIs occurrence and height variation versus solar activities, and the EFIs at low altitudes seem to be related to the seed associated with atmospheric gravity wave.
AB - With an improved method for retrieving the equatorial F region irregularities (EFIs) from radio occultation measurements, a huge amount of S4 index profiles from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites is employed to study the solar cycle variation of global EFIs during the period of 2007 to 2017. This full solar cycle data show that impacts of the solar activity on the occurrence rates and heights of EFIs are notable and complex. The occurrence rates of EFIs at higher altitude (greater than 500 km) increase with increasing the solar activity. The mean heights ((Formula presented.)) and heights standard deviation (σh) of EFIs at higher altitudes do not show clearly the solar activity dependence. On the other hand, the occurrence rates of EFIs at entire altitudes (from 150 to 800 km) do not have clear relation with the solar activity. The (Formula presented.) and σh of EFIs at entire altitudes increase with increasing the solar activity. Moreover, the dependence of the occurrence rates of EFIs on the solar activity are the strongest in the equinoxes, weaker in winter and weakest in summer. The electric fields and corresponding seasonal variation can account for the EFIs occurrence and height variation versus solar activities, and the EFIs at low altitudes seem to be related to the seed associated with atmospheric gravity wave.
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U2 - 10.1029/2018JA025936
DO - 10.1029/2018JA025936
M3 - Article
AN - SCOPUS:85056860110
SN - 2169-9380
VL - 123
SP - 9775
EP - 9787
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
IS - 11
ER -
