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AGU: Geophysical Research Letters

 

Keywords

  • ionospheric migrating tides
  • stratospheric sudden warning

Index Terms

  • Ionosphere: Ionosphere/atmosphere interactions (0335)
  • Ionosphere: Ionospheric dynamics

Abstract

GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L02101, 6 PP., 2012
doi:10.1029/2011GL050248

Observational evidence of ionospheric migrating tide modification during the 2009 stratospheric sudden warming

Key Points
  • Day-to-day variarions of ionospheric tidal signatures during SSW
  • The migrating tides are major drivers responsible to ionospheric variation
  • The nonmigrating tides account for ~20% of ionospheric varation

J. T. Lin

Institute of Space, Astrophysical and Plasma Sciences, National Cheng Kung University, Tainan, Taiwan

C. H. Lin

Department of Earth Science, National Cheng Kung University, Tainan, Taiwan

Earth Dynamic System Research Center, National Cheng Kung University, Tainan, Taiwan

L. C. Chang

Institute of Space Science, National Central University, Chung-Li, Taiwan

H. H. Huang

Institute of Space Science, National Central University, Chung-Li, Taiwan

J. Y. Liu

Institute of Space Science, National Central University, Chung-Li, Taiwan

Center for Space and Remote Sensing Research, National Central University, Chung-Li, Taiwan

A. B. Chen

Institute of Space, Astrophysical and Plasma Sciences, National Cheng Kung University, Tainan, Taiwan

C. H. Chen

Department of Geophysics, Kyoto University, Kyoto, Japan

C. H. Liu

Academia Sinica, Taipei, Taiwan

In this paper, modifications of the ionospheric tidal signatures during the 2009 stratospheric sudden warming (SSW) event are studied by applying atmospheric tidal analysis to ionospheric electron densities observed using radio occultation soundings of FORMOSAT-3/COSMIC. The tidal analysis indicates that the zonal mean and major migrating tidal components (DW1, SW2 and TW3) decrease around the time of the SSW, with 1.5–4 hour time shifts in the daily time of maximum around EIA and middle latitudes. The typical ionospheric SSW signature: a semi-diurnal variation of the ionospheric electron density, featuring an earlier commencement and subsidence of EIA, can be reproduced by differencing the migrating tides before and during the SSW period. Our results also indicate that the migrating tides represent ∼80% of the ionospheric tidal components at specific longitudes, suggesting that modifications of the migrating tides may be the major driver for producing ionospheric changes observed during SSW events, accounting for greater variability than the nonmigrating tides that have been the focus of previous studies.

Received 3 November 2011; accepted 14 December 2011; published 19 January 2012.

Citation: Lin, J. T., C. H. Lin, L. C. Chang, H. H. Huang, J. Y. Liu, A. B. Chen, C. H. Chen, and C. H. Liu (2012), Observational evidence of ionospheric migrating tide modification during the 2009 stratospheric sudden warming, Geophys. Res. Lett., 39, L02101, doi:10.1029/2011GL050248.

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