Key;
Laboratory;
of;
lonospheric;
Environment,;
Institute;
of;
Geology;
and;
Geophysics,;
Chinese;
Academy;
of;
Sciences,;
Beijing;
100029,;
China,";
National;
Observatory;
of;
Space;
Environment,;
Institute;
of;
Geology;
and;
Geophysics,;
Chinese;
Academy;
of;
Sciences,;
Beijing;
100029,;
China,";
of;
Chinese;
Academy;
of;
Sciences,;
Beijing;
100049,;
China;