Influence of the Tidal Wind System on the Frequency of Sporadic‐ E Occurrence

Sporadic‐ E (E S ) data from Japan were presented to show the temporal variations in sporadic‐ E blanketing frequency (ƒ b E S ), virtual height ( h ′ E S ), and frequency of occurrence. Tidal winds were substituted into the wind‐shear theory of E S to calculate electron density profiles and determine the influence of the tidal winds in the asymmetry of the E S occurrence variation. Results showed that the tidal wind model used was not strong enough to significantly influence the formation of molecular ion E S layers, but that the winds did have the proper orientation to accumulate and layer metallic ions in the late afternoon. The role of metallic ions in afternoon E S will have to be established.