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Detailed Reference Information |
Goncharenko, L., Salah, J., Crowley, G., Paxton, L.J., Zhang, Y., Coster, A., Rideout, W., Huang, C., Zhang, S., Reinisch, B. and Taran, V. (2006). Large variations in the thermosphere and ionosphere during minor geomagnetic disturbances in April 2002 and their association with IMF By. Journal of Geophysical Research 111: doi: 10.1029/2004JA010683. issn: 0148-0227. |
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We investigate the variations in the thermosphere and ionosphere using multi-instrument observations during the April 2002 period, with a particular focus on periods during small geomagnetic disturbances. Large and long-lasting reductions in the daytime electron density were observed at midlatitudes by incoherent scatter radars, ionosondes, and GPS receivers. These reductions reached 30--50% and were observed over an extended longitudinal area. They propagated to middle latitudes (35--40¿N) in the case of a weak geomagnetic disturbance (Kp = 3-) and to low latitudes (0--10¿N) in the case of a stronger disturbance (Kp = 5-). Data from the GUVI instrument aboard the TIMED satellite reveal a reduction in the daytime O/N2 ratio in the coincident area. Similar decreases are also predicted by the TIMEGCM/ASPEN model in both O/N2 ratio and electron density, though the magnitude of the decrease from the model is smaller than observed. We suggest that these ionospheric and thermospheric disturbances result from high-latitude energy input and efficient transport of regions with reduced O/N2 to lower latitudes. We discuss the possible role of a strong positive By component of the interplanetary magnetic field in the transport of regions with reduced O/N2. |
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Abstract |
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Keywords
Atmospheric Composition and Structure, Thermosphere, composition and chemistry, Ionosphere, Ionospheric disturbances, Magnetospheric Physics, Magnetosphere/ionosphere interactions, Magnetospheric Physics, Magnetic storms and substorms, Atmospheric Processes, Thermospheric dynamics |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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