Meridional gradients of the neutral temperature in the dayside summer E-region

• Main Authors: Sawako Maeda, Satonori Nozawa
• Format: Report
• Language: English
• Published: Kyoto University of Art and Design 2000
• Subjects: EISCAT; Advances in polar upper atmosphere research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=6309; http://id.nii.ac.jp/1291/00006309/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=6309&item_no=1&attribute_id=18&file_no=1

A special measurement using the European Incoherent Scatter (EISCAT) UHF radar was conducted on July 01, 1998 to observe the dayside summer ￡-region meridional temperature gradient. The purpose of this study is to examine whether the temperature gradient obtained from the direct temperature measurement is consistent with the temperature gradient deduced from the neutral velocity measured by the EISCAT Common Program 2 (CP-2) (S. Maeda et at., J. Geophys. Res., 104, 19871, 1999). It is suggested that the meridional temperature gradient lay in the range between - 0.2 K/km and 0.2 K/km from 99 to 108 km heights in spite of rather large errors of about 0.1 K/km arising from various causes. The magnitude was about 4 times greater than that deduced from the CP-2 data. A lack of consistency between them was attributed to the fact that the former one represented rather instantaneous data, but the latter was hourly averaged. The measured neutral velocity is also presented.