Lower E region second-order statistics and wind-field measurements at low latitudes and their connection to equatorial valley radar echoes

In the equatorial valley-region the interplay of neutral and plasma forces is difficult to separate given the Earth's magnetic field geometry. In addition, this region has been difficult to observe with both ground- and satellite-based instruments. However, from the observations available, mainly radar echoes, the region shows a significant structure in both time and space. Such structure points towards the influence of waves from lower altitudes that either propagate directly vertically, or indirectly via the E-region dynamo. In this work, we present the preliminary results of lower E region winds under and south of the magnetic equator obtained with a newly developed and installed spread-spectrum multi-static radar network called SIMONe. SIMONe allows the estimation of horizontal wind fields with a few tens of kilometer and a few hundreds of meters horizontal and vertical resolutions, respectively. In addition, by exploiting second-order statistics of measured projected velocities, autocorrelation, spectra and second-order structure functions of the wind field are obtained directly without the need of regularization. The preliminary results of both networks under different geophysical and geometrical (magnetic) conditions will be presented and discussed, with a special emphasis on their possible contributions to the equatorial valley region.