Japan Geoscience Union Meeting 2022

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[J] Oral

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

[P-EM15] Heliosphere and Interplanetary Space

Sun. May 22, 2022 3:30 PM - 5:00 PM 105 (International Conference Hall, Makuhari Messe)

convener:Kazumasa Iwai(Institute for Space–Earth Environmental Research (ISEE), Nagoya University), convener:Yasuhiro Nariyuki(Faculty of Education, University of Toyama), Masaki N Nishino(Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science), convener:Ken Tsubouchi(University of Electro-Communications), Chairperson:Kazumasa Iwai(Institute for Space–Earth Environmental Research (ISEE), Nagoya University), Ken Tsubouchi(University of Electro-Communications)

4:30 PM - 4:45 PM

[PEM15-05] Analysis of cosmic-ray north-south anisotropy using multipoint observations

*Masayoshi Kozai1, Kazuoki Munakata2, Chihiro Kato2, Akira Kadokura1,3,4, Ryuho Kataoka3 (1.PEDSC/ROIS-DS, 2.Shinshu Univ., 3.NIPR, 4.SOKENDAI)

Keywords:Galactic cosmic rays, Solar modulation, Anisotropy, Ground-based observation

The spatial distribution of cosmic-ray density is an essential parameter in understanding the solar modulation of galactic cosmic rays. In particular, the radial density gradient is a comparable index of solar modulation to the local cosmic-ray intensity, which has been widely used. The cosmic-ray north-south anisotropy sensitively reflects this density gradient through diamagnetic drift in the interplanetary magnetic field (IMF). In recent years, we have developed a correction method of the cosmic-ray intensity using meteorological reanalysis data. This method makes it possible to compare the measurements at independent stations directly. Furthermore, we started cosmic ray observation at Syowa station, Antarctica. Taking these advantages, we are developing a new analysis method of north-south anisotropy by comparing measurements in the north and south hemispheres. We report the results, such as polarity reversal of the anisotropy due to the IMF sector.