Cold;
and;
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Regions;
Environmental;
&;
Engineering;
Research;
Institute,;
Chinese;
Academy;
of;
Sciences,;
Lanzhou;
730000,;
China;
School;
of;
Electrical;
Engineering,;
Wuhan;
University,;
Wuhan;
430072,;
China;
Cold;
and;
Arid;
Regions;
Environmental;
&;
Engineering;
Research;
Institute,;
Chinese;
Academy;
of;
Sciences,;
Lanzhou;
730000,;
China;
Cold;
and;
Arid;
Regions;
Environmental;
&;
Engineering;
Research;
Institute,;
Chinese;
Academy;
of;
Sciences,;
Lanzhou;
730000,;
China;
Cold;
and;
Arid;
Regions;
Environmental;
&;
Engineering;
Research;
Institute,;
Chinese;
Academy;
of;
Sciences,;
Lanzhou;
730000,;
China;
broadband; interferometer,; cloud-to-ground; lightning,; preliminary; breakdown,; stepped; leader.;