Vertical variance analysis of geomagnetic disturbance during solar cycle 23

Abstract

The geomagnetic field consists of temporal variations induced primarily by the variations in the solar wind and embedded interplanetary magnetic field. 34 stations across the Earth have been categorized in this paper on the basis of their geomagnetic disturbance during solar cycle 23 (1997-2008). The Vertical Variance (VV) disturbance quantifier has been used to develop such profile. The latitude profile of geomagnetic disturbance has been found to exhibit a typical ‘Knee’ behaviour, with the fluctuation content seen to rise sharply beyond this critical latitude determined near 52° latitude. The increasing trend in geomagnetic fluctuation content however is seen to end around the auroral oval beyond where abrupt variations has been observed indicating the transition from closed to open magnetic field lines. The physical mechanism behind this trend has also been explored. The VV analysis of geomagnetic disturbance has revealed prominent features of solar wind – magnetosphere coupling.