Japan Geoscience Union Meeting 2014

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Oral

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

[P-EM36_28PM2] Physics and Chemistry in the Atmosphere and Ionosphere

Mon. Apr 28, 2014 4:15 PM - 6:00 PM 312 (3F)

Convener:*Yuichi Otsuka(Solar-Terrestrial Environment Laboratory, Nagoya University), Takuya Tsugawa(National Institute of Information and Communications Technology), Seiji Kawamura(National Institute of Information and Communications Technology), Chair:Mitsuru Matsumura(Center for Space Science and Radio Engineering, University of Electro-Communications), Tatsuhiro Yokoyama(National Institute of Information and Communications Technology)

5:15 PM - 5:30 PM

[PEM36-P09_PG] Atmospheric origin of small-scale magnetic fluctuations as observed by CHAMP above the ionosphere

3-min talk in an oral session

*Tadashi AOYAMA1, Toshihiko IYEMORI2, Kunihito NAKANISHI1 (1.Graduate School of Science, Kyoto University, 2.Graduate School of Science, Kyoto University)

Keywords:field-aligned current, ionospheric dynamo, atmospheric gravity wave, acoustic resonance, CHAMP satellite, typhoon

We analyzed magnetic field data obtained by a LEO(Low Earth Orbit) satellite, CHAMP(altitude 300~450 km), and found out the global distribution of the short-period(10~40 s) and small-amplitude(0.1~5 nT) magnetic fluctuations in middle and low latitudes. We have reported that these fluctuations are small-scale structure(~100 km) of the field-aligned currents generated by dynamo action in the ionospheric E-layer and the dynamos are caused by the atmospheric gravity waves (horizontal scale is ~100 km) because of the characteristics of geographical and seasonal dependence of their amplitude.In this paper, we focus on the mesoscale meteorological events to clarify the atmospheric origin such as typhoon which is possible to generate atmospheric gravity waves, and compare with magnetic fluctuations as observed by the CHAMP satellite above the ionosphere. We trace from the location of CHAMP to each footpoint in the E-layer along geomagnetic field line, and then compared with meteorological phenomena beneath the footpoint.As a result, we detected large amplitudes of geomagnetic fluctuation above typhoons.