Forecast assessment of topside spread F at Jicamarca

Abstract

The Jicamarca Unattended Long Term Investigations of the Ionosphere and Atmosphere (JULIA) radar operated from August 1996 through the present time, making a total of approximately 1500 nights of ionospheric irregularities associated with equatorial spread F (ESF) observations under different seasons, solar flux levels, and geomagnetic conditions. The climatology, persistence, and correlation with the phase of the Moon of premidnight and postmidnight irregularities are evaluated, and different forecasting tools are compared. During equinox, 1 day persistence information improves the forecast over climatology alone for most solar flux and geomagnetic activity conditions, with a significant improvement during periods at low solar flux. December solstice ESF observations show a high correlation with the lunar phase, with periods close to the full Moon presenting the highest probability of ESF occurrence. Using this information for geomagnetically quiet periods during December solstice, we further improve the forecast over the climatological model. For postmidnight and premidnight June solstice ESF, however, climatology still gives the best forecasting results.