Statistical study of the DP2 enhancement at the dayside dip-equator compared to low latitudes

Abstract

It has been largely investigated and established that the DP2 events are enhanced at dip-equator compared to low latitudes. Studies by several authors showed various enhancement ratio values of DP2 amplitude at the dayside dip-equator relative to those at low latitudes. In order to quantify this enhancement ratio, we carried out a statistical study on this phenomenon using the ground magnetometer data at locations ranging from polar cap to dip-equator over the African, Asian and American sector. Our result gave an enhancement ratio which shows a diurnal variation with a maximum value around 12:00 LT and is correlated with the regular variation of the geomagnetic H-component. The longitudinal variation of the enhancement ratio of the DP2 exhibits high values over the American sector compared to Asian sector and African sector which have lowest values. This longitudinal dependence is similar to that of the equatorial electrojet magnetic effect.