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Polar Cap Disturbances: Mesosphere and Thermosphere-Ionosphere Response to Solar-Terrestrial InteractionsThe Polar Cap is the Upper-Atmosphere cum Mag-netosphere region which is enclosed by the poleward boundary of the Auroral Oval and is threaded by open geomagnetic tield lines. In this region, there is normally a steady precipition (Polar "drizzle") of low energy (w 300eV) electrons that excite optical emissions from the ionosphere. At times, enhanced ionization patches are formed near the Dayside Cusp regions that drift across the Polar Cap towards the Night Sector of the Auroral Oval. Discrete auroral arcs and auroras formed during Solar Magnetic Cloud (SMC)/Coronal Mass Ejection (CME) events are also observed in the Polar Cap. Spectrophotometric observations of all these Polar Cap phenomena provide a measure of the average energy as well a energy flux of the electrons precipitating in the Polar Cap region during these disturbances. Such measurements also point to modulations of the Polar Cap Mesosphere-Lower Thermosphere (MLT) air density and temperature by zonally symmetric tides whose Hough functions peak in the Polar region. MLT cooling during Stratospheric Warming events and their relation to Polar Vortex and associated Gravity wave activities are also observed at the Polar Cap sites.
Document ID
20040016249
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Sivjee, G.
(Embry-Riddle Aeronautical Univ. United States)
McEwen, D.
(Saskatchewan Univ. Saskatoon, Saskatchewan, Canada)
Walterscheid, R.
(Aerospace Corp. United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Publication Information
Publication: Proceedings of the 28th Annual European Meeting on Atmospheric Studies by Optical Methods
Subject Category
Geophysics
Funding Number(s)
CONTRACT_GRANT: NSF OPP-99-09339
CONTRACT_GRANT: NSF OPP-99-10950
CONTRACT_GRANT: NAG5-10066
CONTRACT_GRANT: NSF ATM-98-04674
Distribution Limits
Public
Copyright
Other

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