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Ann. Geophys., 25, 1555-1568, 2007
www.ann-geophys.net/25/1555/2007/
© European Geosciences Union 2007
Morphology in the total electron content under geomagnetic disturbed conditions: results from global ionosphere maps
Zhao Biqiang1, Wan Weixing1, Liu Libo1, and Mao Tian1,2,3
1Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
2Wuhan Institute of Physics and Mathematics, CAS, Wuhan 430071, China
3Graduate School of Chinese Academy of Sciences, Beijing, China
Abstract. Using 8-year global ionosphere maps (GIMs) of TEC products
from the Jet Propulsion Laboratory (JPL), we make a statistical study on the
morphology of the global ionospheric behaviors with respect to the
geomagnetic disturbances. Results show that the behaviors of TEC during
geomagnetic storm present clear seasonal and local time variations under
geomagnetic control in a similar way as those of NmF2 (Field and
Rishbeth, 1997). A negative phase of TEC occurs with high probability in the
summer hemisphere and most prominent near the geomagnetic poles, while
a positive phase is obvious in the winter hemisphere and in the far pole
region. A negative storm effect toward lower latitudes tends to occur from
post-midnight to the morning sector and recedes to high latitude in the
afternoon. A positive storm effect is separated by geomagnetic latitudes and
magnetic local time. Furthermore, ionospheric responses at different local
time sectors with respect to the storm commencement shows very different
developing processes corresponding to the evolution of the geomagnetic
storm. A daytime positive storm effect is shown to be more prominent in the
American region than those in the Asian and European regions, which may
suggest a longitudinal effect of the ionospheric storm.
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