The Tenth Symposium on Polar Science/Ordinary sessions: [OS] Space and upper atmospheric sciences, Wed. 4 Dec. /Entrance Hall (1st floor) at National Institute of Polar Research (NIPR

Chris Hall

Ingemar Haggstrom

Masaki Tsutsumi

Ogawa Yasunobu

Satonori Nozawa

Yoshihiro Tomikawa

National Institute of Polar Research Repository

  Ion temperature and velocity variations in the D- and E-region polar ionosphere during stratospheric sudden warming  Yasunobu Ogawa1, Satonori Nozawa2, Masaki Tsutsumi1, Yoshihiro Tomikawa1, Chris Hall3, Ingemar Haggstrom4 1National Institute of Polar Research / SOKENDAI, Tokyo, Japan,  2ISEE, Nagoya University, Nagoya, Japan,  3UiT The Arctic University of Norway, Tromso, Norway,  4EISCAT Scientific Association, Kiruna, Sweden  We analyzed ion temperature and velocity observed by the European Incoherent Scatter (EISCAT) UHF radar at Tromsoe (69.6 deg N, 19.2 deg E) during a stratospheric sudden warming (SSW) that occurred in January-February 2017. The zonal ion velocities at 85-100 km height reversed approximately 8 days earlier than the zonal wind reversal in the upper stratosphere. Ion temperature at 85-95 km decreased simultaneously with the zonal ion velocity reversal at the same altitude, and vertical ion velocity changes of about +/-2 m/s were also seen from ˜8 days before the SSW onset. Downward propagation speed of the vertical ion velocity variation was ˜0.01 m/s, as well as that of ion temperature variation. We also found that the ion temperature variations in the daytime were close to those of ambipolar diffusion coefficients derived from the the Nippon/Norway Tromsoe Meteor Radar (NTMR) data at the same altitude even when geomagnetic activity is moderate. We will discuss energy and momentum exchanges between ions and neutrals at 85-95 km based on the observational results during SSW.  

Ion temperature and velocity variations in the D- and E-region polar ionosphere during stratospheric sudden warming

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Ion temperature and velocity variations in the D- and E-region polar ionosphere during stratospheric sudden warming

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