multi-day periodicities in thermosphere density during the declining phase of solar cycle 23
DESCRIPTION
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. Outline. 1. CHAMP Density in 2005 - PowerPoint PPT PresentationTRANSCRIPT
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
Outline
1. CHAMP Density in 2005
2. Solar Activity Dependence of Multi-day Periodicities
3. Preliminary Comparison between Data and TIEGCM
CHAMP density in 2005
27 days/3
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.
Thermospheric density response to solar wind: 2005-2007
ascend
descend
Thermospheric density response to solar wind: 2002-2004
ascend
descend
Solar Activity Dependence
Latter part of the declining phase
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.
Correlation from 2002 to 2007
1. 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.
Summary I
Preliminary Comparison for Mass Density
Preliminary Comparison for O/N2
Lei, J., et al. (2008), Ionosphere Response to Solar Wind High-Speed Streams, Geophys. Res. Lett., doi:10.1029/2008GL035208
Ionospheric response
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.
Summary II