A review of radar and satellite beacon observations of atmospheric gravity waves at Syowa Station

• Main Author: Tadahiko Ogawa
• Format: Report
• Language: English
• Published: Solar-Terrestrial Environment Laboratory, Nagoya University 1998
• Subjects: Syowa Station; Antarc*; Antarctica; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2311; http://id.nii.ac.jp/1291/00002311/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2311&item_no=1&attribute_id=18&file_no=1

We review the observations of atmospheric gravity waves in the upper mesosphere and the thermosphere that have been carried out at Syowa Station, Antarctica, by means of a meteor radar and satellite beacon wave reception. Occurrence probability and altitude distribution of meteor echoes and mean wind profiles in the upper mesosphere are presented to show that our results are nearly consistent with those in the opposite hemisphere. Gravity waves detected with the meteor radar are well manifested in the sodium abundance (column density) and density perturbations simultaneously measured with a sodium lidar. An evidence is presented that during an auroral substorm, strong winds appeared in accord with a gradual decrease in the sodium abundance. About 400 medium-scale traveling ionospheric disturbances (MSTIDs) in the F region were detected with NNSS satellite beacon waves. Statistical analysis indicates that MSTIDs appear quite often during geomagnetically quiet and moderately disturbed conditions and that most of them propagate from south toward the equator. These findings together with the diurnal and seasonal variations of the MSTID occurrences are fairly consistent with previous mid-latitude results. In the future, we need continuous long-term observations at Syowa Station to understand the gravity wave characteristics and the effects of gravity waves upon the global circulation, energy budget in the atmosphere, and thermosphere-middle atmosphere coupling.