LIDAR OBSERVATIONS OF THE MESOSPHERIC SODIUM LAYER AT SYOWA STATION, ANTARCTICA

• Main Authors: ノムラ アキオ, イワサカ ヤスノブ, フクニシ ヒロシ, ヒラサワ タケオ, カワグチ サダオ, カノ テツオ, Akio NOMURA, Yasunobu IWASAKA, Hiroshi FUKUNISHI, Takeo HIRASAWA, Sadao KAWAGUCHI, Tetsuo KANO
• Format: Report
• Language: English
• Published: ABSTRACT 1987
• Subjects: Syowa Station; Antarc*; Antarctica; E. Antarctica; Polar meteorology and glaciology; Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3539; http://id.nii.ac.jp/1291/00003539/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3539&item_no=1&attribute_id=18&file_no=1

The mesospheric sodium layer has been measured on 42 nights during the period from April to October 1985 at Syowa Station (69°00′E, 39°35′E), Antarctica, by observation of the resonance scattering of a tuned dye laser beam, which has been made as part of the Middle Atmosphere Program (MAP). There are no pronounced seasonal variations in abundance, the peak height and the width of the sodium layer. No enhancement of aboundance in winter has been observed, which is different from those obtained at mid-latitudes in the northern hemisphere. It is, however, interesting to show the oscillatory variation in abundance with a period of about 40 days. The nocturnal variations of sodium profile show wave-like structure with a vertical wavelength of 10 to 16km and a period of 4 to 8h, which suggests the existence of gravity wave. During sodium lidar measurements under auroral activity, it has been observed by chance that the layer is disturbed by auroral break-up associated with the change of cosmic noise absorption (CNA).