The seasonal variation of night-time sodium layer at 33゜N

• Main Authors: Michihiro Uchiumi, Motokazu Hirono, Motowo Fujiwara
• Format: Report
• Language: English
• Published: Department of Physics, Faculty of Science, Kyusyu University 1985
• Subjects: Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1765; http://id.nii.ac.jp/1291/00001765/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1765&item_no=1&attribute_id=18&file_no=1

Measurements of the night-time mesospheric sodium layer have been performed since 1977,using a dye lidar at Fukuoka (33.4°N, 130.2°E). The results measured during 1983 are presented in this paper. The annual average in abundance (4.2×(10)^<13>/m^2) is in good agreement with twilight observation made at Kitt Peak (32°N) and lidar measurements at Sao Jose dos Campos (23°S). The annual average of peak height is 93km. Averaging the measurements every three months except for the value on the peak day of the shower, the sodium abundance shows seasonal variation by a factor of 2 with maximum (5.3×(10)^<13>/m^2) in winter and with minimum (2.6×(10)^<13>/m^2) in spring. The abundance increased on the night during the Perseids meteor shower, which is remarkable, since such correlative increment to permanent meteor shower has not been seen at low latitudes by lidar or twilight observations.