First Simultaneous Lidar Observations of Thermosphere-Ionosphere Fe and Na (TIFe and TINa) Layers at McMurdo (77.84°S, 166.67°E), Antarctica With Concurrent Measurements of Aurora Activity, Enhanced Ionization Layers, and Converging Electric Field.

Autor: Chu X; Cooperative Institute of Research in Environmental Sciences and Department of Aerospace Engineering Sciences University of Colorado Boulder Boulder CO USA., Nishimura Y; Department of Electrical and Computer Engineering and Center for Space Physics Boston University Boston MA USA., Xu Z; Bradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State University Blacksburg VA USA., Yu Z; Harbin Institute of Technology Shenzhen China., Plane JMC; School of Chemistry University of Leeds Leeds UK., Gardner CS; Department of Electrical and Computer Engineering University of Illinois Urbana IL USA., Ogawa Y; National Institute of Polar Research Tokyo Japan.
Jazyk: angličtina
Zdroj: Geophysical research letters [Geophys Res Lett] 2020 Oct 28; Vol. 47 (20), pp. e2020GL090181. Date of Electronic Publication: 2020 Oct 19.
DOI: 10.1029/2020GL090181
Abstrakt: We report the first simultaneous, common-volume lidar observations of thermosphere-ionosphere Fe (TIFe) and Na (TINa) layers in Antarctica. We also report the observational discovery of nearly one-to-one correspondence between TIFe and aurora activity, enhanced ionization layers, and converging electric fields. Distinctive TIFe layers have a peak density of ~384 cm -3 and the TIFe mixing ratio peaks around 123 km, ~5 times the mesospheric layer maximum. All evidence shows that Fe + ion-neutralization is the major formation mechanism of TIFe layers. The TINa mixing ratio often exhibits a broad peak at TIFe altitudes, providing evidence for in situ production via Na + neutralization. However, the tenuous TINa layers persist long beyond TIFe disappearance and reveal gravity wave perturbations, suggesting a dynamic background of neutral Na, but not Fe, above 110 km. The striking differences between distinct TIFe and diffuse TINa suggest differential transport between Fe and Na, possibly due to mass separation.
(©2020. The Authors.)
Databáze: MEDLINE
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