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Multi-day Periodicities in Thermosphere Density during the Declining Phase of Solar Cycle 23 PowerPoint Presentation
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Multi-day Periodicities in Thermosphere Density during the Declining Phase of Solar Cycle 23

Multi-day Periodicities in Thermosphere Density during the Declining Phase of Solar Cycle 23

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Multi-day Periodicities in Thermosphere Density during the Declining Phase of Solar Cycle 23

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  1. Multi-day Periodicities in Thermosphere Density during the Declining Phase of Solar Cycle 23 Jiuhou Lei,Jeffrey P. Thayer, Jeffrey M. Forbes, Eric K. Sutton, and R. Steven Nerem Department of Aerospace Engineering Sciences University of Colorado

  2. Outline 1. CHAMP Density in 2005 2. Solar Activity Dependence of Multi-day Periodicities 3. Preliminary Comparison between Data and TIEGCM

  3. 27 days/3 CHAMP density in 2005 Lei, J., J. P. Thayer, J. M. Forbes, E. K. Sutton, and R. S. Nerem (2008), Rotating solar coronal holes and periodic modulation of the upper atmosphere, Geophys. Res. Lett., 35, L10109, doi:10.1029/2008GL033875.

  4. Thermospheric density response to solar wind: 2005-2007 ascend descend

  5. Thermospheric density response to solar wind: 2002-2004 ascend descend

  6. Latter part of the declining phase Solar Activity Dependence

  7. Correlation between density oscillations and Kp Percent of the band-pass filter density residuals to 11-day running mean. The band-pass filter was centered at the period of 9 days.

  8. Correlation from 2002 to 2007

  9. Summary I • The neutral densities show the presence of several prominent periods around 9, 7, and 5 days from 2004-2007, with the most pronounced periodicities of 9 and 7 days observed in 2005, and 2006, respectively. • 2. The periodicity of neutral density highly correlates with that of geomagnetic activity and solar wind parameters during the latter part of the declining phase. This solar activity dependence of the periodicities is explained by the corresponding variations of high-speed solar wind and the associated geomagnetic activity. Lei, J., et al. (2008b), Global thermospheric density variations caused by high-speed solar wind streams during the declining phase of solar cycle 23, J. Geophys. Res., doi:10.1029/2008JA013433, in press.

  10. Preliminary Comparison for Mass Density

  11. Preliminary Comparison for O/N2

  12. Ionospheric response Lei, J., et al. (2008), Ionosphere Response to Solar Wind High-Speed Streams, Geophys. Res. Lett., doi:10.1029/2008GL035208

  13. Summary II 9- and 7-day periodic oscillations are also present in the global mean Total Electron Content (TEC) from 1 January 2005 to 31 December 2006. Spectral analysis indicates that the pronounced periodicities of 9 and 7 days observed in TEC are associated with variations in solar wind high-speed streams and geomagnetic activity.