the day-to-day longitudinal variability of the global ionospheric density distribution: preliminary...
TRANSCRIPT
The day-to-day longitudinal variability of the global ionospheric
density distribution: Preliminary results
E.E. Pacheco and E. Yizengaw
Institute for Scientific Research, Boston College, Boston, USA
LISN WORKSHOP, São José dos Campos, SP, Brazil, Nov 7-10, 2011
Outline
• Introduction• Instruments and methodology• Observations• Conclusions
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Introduction
• Ionospheric density is a important parameter• The low latitude ionospherIc density changes
can affect communication and navigation signals
• Electrodynamics that controls the ionospheric density distribution is not yet fully understood
• Wind driven electric field systems modify the density structure of the ionosphere.
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INSTRUMENTS
• GPS RECEIVERS NETWORKMadrigal• CHAMP – topside TECAlt ~ 340 km, orbit~98 degree, period~100min• TIMED-TIDI- Zonal wind in the E regionAlt~600 km
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METHODOLOGY
• Geomagnetic quiet time conditions, 2008.• Global TEC map as a function of longitude and
latitude at fix local times (bins: 10 longitude by 2 latitude)
• Day-to-day variability of TEC which includes the wavenumber four structures during day and nightside
• TIDI’s global zonal wind maps ~ 60 days average
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Motivation
• What causes the longitudinal density variability, including the formation of wavenumber-4, during geomagnetic quiet period?
• Does zonal or meridional wind play a vital role for the formation of wavenumber-4 structure?
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Dayside
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Dayside
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Nightside
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ZONAL WIND FROM TIDI INSTRUMENT
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MERIDIONAL WIND FROM TIDI INSTRUMENT
C/NOFS and ROCSAT-1 ION DRIFTS
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Conclusions
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• The ionospheric density is longitudinal dependent• Wavenumber-4 is detected on the TEC
measurements• Wavenumber-4 structure can extend to post-
midnight hours• It seems the zonal wind has more impact on the
formation of wavenumber-4 structure than the meridional wind, but more studies are needed to understand the electrodynamics that controls the longitudinal variability.
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Thank you