Sporadic E

Irregular scattered patches of relatively dense ionization that develop seasonally within the E region and that reflec­t and scatter frequencies up to 150 MHz. Note 1: The sporadic E is a regular day­time occurrence over the equatorial regions and is common in the temper­ate latitudes in late spring, early summer and, to a lesser degree, in early winter. Note 2: At high, i.e., polar, latitudes, sporadic E can accompany auroras and associated disturbed magnetic conditions. Note 3: The sporadic E can sometimes support reflec­tions for distances up to 1000 miles or more at frequencies up to 150 MHz