Japan Geoscience Union Meeting 2015

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International Session (Oral)

Symbol P (Space and Planetary Sciences) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM06] Mesosphere-Thermosphere-Ionosphere Coupling in the Earth's Atmosphere

Wed. May 27, 2015 11:00 AM - 12:45 PM A01 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Huixin Liu(Earth and Planetary Science Division, Kyushu University SERC, Kyushu University), Yuichi Otsuka(Solar-Terrestrial Environment Laboratory, Nagoya University), Libo Liu(Institute of Geology and Geophysics, Chinese Academy of Sciences), Atsuki Shinbori(Research Institute for Sustainable Humanosphere (RISH), Kyoto University), Chair:Atsuki Shinbori(Research Institute for Sustainable Humanosphere (RISH), Kyoto University)

12:15 PM - 12:30 PM

[PEM06-16] First simultaneous observation of Ca+ densities in the E region and MSTIDs in the F region

*Mitsumu K. EJIRI1, Takuo TSUDA2, Takanori NISHIYAMA1, Makoto ABO3, Michi NISHIOKA4, Takashi MARUYAMA4, Akinori SAITO5, Takuji NAKAMURA1 (1.National Institute of Polar Research, 2.The University of Electro-Communications, 3.Graduate School of System Design, Tokyo Metropolitan University, 4.National Institute of Information and Communications Technology, 5.Department of Geophysics, Graduate School of Science, Kyoto University)

Keywords:resonance scattering lidar, Ca+, medium scale traveling ionospheric disturbances, GPS-TEC, sporadic E layer

In the mesosphere and lower thermosphere region, there are permanent layers of metal atoms and ions, the source of which is vaporization of cosmic dust and meteoroids during their entry into the Earth's atmosphere. Some metal atom layers e.g. Na, K, Ca, and Fe layers, and only Ca+ (Calcium ion) can be observed by ground-based resonance scattering lidars. The National Institute of Polar Research (NIPR) is developing a new resonance scattering lidar system with a frequency-tunable laser. The lidar transmitter is based on injection-seeded, pulsed alexandrite laser for 768-788 nm and a second-harmonic generation (SHG) unit for 384-394 nm. The new lidar is able to measure density variations of minor constituents including Ca+ (393.477 nm). As a part of the development, observation tests are carried out at NIPR (35.7N, 139.4E) since 2013, and we got the first light from Ca+ layer on 21 August, 2014. The Ca+ density profiles were obtained for 〜5 hours (23:13 LT-28:28 LT) with temporal and height resolutions of 1 min and 15 m, respectively. During the night, high density and narrow Ca+ layer was observed. The layer descended from 〜107 km to 99 km with quasi-periodic density perturbations until 〜17 UT and then stayed at around 99 km until sunrise. At the same night, sporadic E (Es) layer was observed with an ionosonde at Kokubunji by National Institute of Information and Communications Technology (NICT) (35.7N, 139.5E), also medium scale traveling ionospheric disturbances (MSTIDs) were observed with the dense GPS receiver network (GEONET). In this presentation, we compare these data in detail and discuss relationships between observed Ca+ density perturbations, Es layer and MSTIDs