Solar Cycle Variations of Topside Electron Density and Temperature: Altitudinal, Latitudinal, and Se

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Solar Cycle Variations of Topside Electron
Density and Temperature Altitudinal,
Latitudinal, and Seasonal Differences. D.
Bilitza(1), P. Richards(2), V. Truhlik(3), T.
Abe(4), L. Triskova(3) (1)Raytheon ITSS, GSFC,
SPDF, Greenbelt, USA (2)NASA, Earth-Sun Systems
Division, Washington DC, USA (3) Institute of
Atmospheric Physics, Praha, Czech Republic (4)
Aerospace Exploration Agency (JAXA), Sagamihara,
Japan
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• Summary
• Goal Determine Te solar cycle variation for
  inclusion in IRI.
• Source Data base of satellite insitu
  measurements and FLIP model
• This Study Solar activity variation of Ne and
  Te at 550, 900, and 2000 km, for MLT 2, and 13,
  during all seasons

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Previous Studies Balan et al., 2001- MU Radar
Balance of gain, loss, and transport processes
for thermal energy can result in increase or
decrease with solar activity.
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Previous Studies Oyama et al., 2002 - Akebono
At high altitudes the heat transport from the
plasmasphere results in an increase with solar
activity.
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Previous Studies Zhang, Holt, 2004 Millstone
Hill
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Database
Akebono, since Feb 1989, 700 10,000 km, -75 -
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Altitudinal Differences Jicamarca latitude
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Altitudinal Differences Jicamarca
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Altitudinal Differences Millstone Hill
Noon
Midnight
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Averages of Akebono electron temperatures versus
solar flux for different altitude ranges during
daytime for summer (top) and winter (right)
conditions seem to indicate an increase with
solar flux at higher altitudes and a decrease for
the lower height range and no significant
seasonal changes.
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Equinox, mid-latitude, noon
550 km
900 km
2000 km
Log(Ne)
Te
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Winter, mid-latitude, midnight
550 km
900 km
2000 km
Log(Ne)
Te
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Noon, Mid-lat
Midnight, Mid-lat
Midnight, Equator
Noon, Equator
600 km
900 km
1500 km
2200 km
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Seasonal Differences
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Mid-latitude, noon, 550 km
Equinox
Summer
Winter
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Mid-latitude, noon, 900 km
Equinox
Summer
Winter
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Mid-latitude, noon, 2000 km
Equinox
Summer
Winter
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Summer
Equinox
Winter
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• Results
• Ne increases with solar activity for all cases.
• Solar cycle effects are strongest at low
  altitudes.
• - Te changes over the solar cycle are generally
  much smaller than
• those of Ne and show a seasonal dependence during
  daytime
• increases in summer, constant or small decrease
  in winter,
• decrease in equinox.
• FLIP generally confirms the Ne trends seen in our
  data base.
• FLIP agrees well with the Te daytime values.
• - During nighttime FLIP overestimates the winter
  values and
• underestimates the summer and equinox data