Geophysical Institute and Department of Atmospheric Sciences, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775-7320, USA

Department of Physics and Astronomy, Clemson University, 118 Kinard Laboratory, Clemson, SC 29631-0978, USA

Department of Physics and Astronomy, Clemson University, 118 Kinard Laboratory, Clemson, SC 29631-0978, USA

Environmental Sensing and Network Group, National Institute of Information and Communications Technology, 4-2-1 Nukui-kita, Koganei, Tokyo 184-8795, Japan