| In this study we focus on the dynamics of the ion drift velocities at low and middle latitudes. We describe how these ion drifts vary in latitude for different longitudes, seasons and specific local times during quiet times.;During quiet times we use data from the ROCSAT-1 satellite to describe the latitude dependence of three main features of the meridional ion drifts; the large-scale upward drifts during daytime, a so-called prereversal enhancement near dusk, and a downward sunrise enhancement. The longitude, latitude and seasonal dependences in these features are influenced by the alignment of the terminators with the magnetic meridian, the flux tube integrated conductivities and the action of diurnal and semidiurnal tides in the lower ionosphere.;We also obtained a description of the zonal ion drifts during quiet times. These drifts show latitude, longitude and seasonal variations, driven by the combined effects of the E-region and F-region winds. Changes in the wind and the F-region Pedersen conductance are responsible for latitude, longitude and seasonal changes in the net superrotation of the ionosphere.;Additionally, we describe storm time perturbations in the ion drifts at the magnetic equator. These perturbations are mainly produced by undershielding and overshielding of the magnetospheric electric field during times when the Interplanetary Magnetic Field is changing. The role of the disturbance dynamo can also be seen in the perturbation drifts at the equator.;Using measurements from the DMSP-F13, F-15 and ROCSAT-1 satellites we are able to describe for the first time, storm-time drift perturbations at the equator observed simultaneously at different local times. |
