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Geomagnetic activity effect on the global ionosphere during the 2007–2009 deep solar minimum
Author(s) -
Chen Yiding,
Liu Libo,
Le Huijun,
Wan Weixing
Publication year - 2014
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2013ja019692
Subject(s) - earth's magnetic field , ionosphere , atmospheric sciences , solar minimum , solar cycle 23 , quiet , environmental science , ionospheric dynamo region , geomagnetic storm , solar cycle , physics , geophysics , solar wind , magnetic field , astronomy , quantum mechanics
In this paper the significant effect of weaker geomagnetic activity during the 2007–2009 deep solar minimum on ionospheric variability on the shorter‐term time scales of several days was highlighted via investigating the response of daily mean global electron content (GEC, the global area integral of total electron content derived from ground‐based GPS measurements) to geomagnetic activity index Ap . Based on a case during the deep solar minimum, the effect of the recurrent weaker geomagnetic disturbances on the ionosphere was evident. Statistical analyses indicate that the effect of weaker geomagnetic activity on GEC variations on shorter‐term time scales was significant during 2007–2009 even under relatively quiet geomagnetic activity condition; daily mean GEC was positively correlated with geomagnetic activity. However, GEC variations on shorter‐term time scales were poorly correlated with geomagnetic activity during the solar cycle descending phase of 2003–2005 except under strong geomagnetic disturbance condition. Statistically, the effects of solar EUV irradiance, geomagnetic activity, and other factors (e.g., meteorological sources) on GEC variations on shorter‐term time scales were basically equivalent during the 2007–2009 solar minimum.