Long-term variations in Sq related to greenhouse gases and Earth?s magnetic field

ANA G. ELIAS; MARTA ZOSSI DE ARTIGAS; BLAS F. DE HARO BARBAS

Boulder, Colorado

Workshop; 6th Workshop on Long-Term Changes and Trends in the Atmosphere; 2010

IAGA - ICMA - CAWSES, National Center for Atmospheric Research (NCAR)

Trends in the solar quiet geomagnetic field variation, Sq, are studied in connection to greenhouse gases increasing concentration and secular variations of the Earth?s magnetic field. Sq variations are a manifestation of ionospheric current systems which flow in the E-region. These currents depend on ionospheric conductivities, which vary with the Earth?s main magnetic field, B, and the electron concentration in the E region, for which foE is a measure of its peak value. B presents secular variations linked to changes in the Earth?s core flow and foE, an increasing trend due to the increasing concentration in greenhouse gases. Based on these facts, a theoretical approximation is first made to assess the expected trends in Sq induced by B secular variations and greenhouse gases increasing concentration. To detect these trends, the Sq variation of the horizontal intensity, H, of magnetic observatories at low and mid-latitudes are analyzed. We find significant trends which may be partially accounted by B secular variations in the respective sites and also by foE trend due to greenhouse gases increasing concentration.