Gravitational separation of the stratospheric air over Syowa, Antarctica and its connection with meteorological fields

• Published in: Atmospheric Science Letters
• Main Authors: Ishidoya, Shigeyuki, Sugawara, Satoshi, Inai, Yoichi, Morimoto, Shinji, Honda, Hideyuki, Ikeda, Chusaku, Hashida, Gen, Machida, Toshinobu, Tomikawa, Yoshihiro, Toyoda, Sakae, Goto, Daisuke, Aoki, Shuji, Nakazawa, Takakiyo
• Other Authors: Institute of Space and Astronautical Science, Japan Society for the Promotion of Science, Ministry of Education, Culture, Sports, Science and Technology, National Institute of Polar Research
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2018
• Subjects: Austral; Syowa Station; Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1002/asl.857; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fasl.857; http://api.wiley.com/onlinelibrary/chorus/v1/articles/10.1002%2Fasl.857; https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/asl.857

To examine gravitational separation of the stratospheric air over Antarctica in austral summer, we collected air samples from altitudes of 10 to 30 km over Syowa Station (69.0°S, 39.6°E) using balloon‐borne cryogenic samplers for the period 1998–2013, and then analyzed them for δ 15 N of N 2 , δ 18 O of O 2 , δ(Ar/N 2 ) and δ 40 Ar. The normalized mass ratio “δ,” calculated using their measured values, decreases with increasing altitude, implying an upward enhancement of the gravitational separation effect. The observed stratospheric δ profiles are generally well reproduced by a two‐dimensional atmospheric model, but the model tends to underestimate the observed δ values in the middle stratosphere above 26 km. We also observe interannual variation in the δ vertical profile in the middle stratosphere. A backward trajectory analysis suggests that this variation is attributable to different horizontal mixing of the stratospheric air over Antarctica from year to year.