NIGHT-TIME DECREASES IN F2 LAYER HEIGHTS AT NEAR CONJUGATE STATIONS IN LOW LATITUDES

An analysis is made of decreases in F-region heights occurring in the night hours at Rarotonga and Maui during the first half of 1958. The probability of height decreases being observed simultaneously at these near conjugate stations is related to Honolulu K-index and to the east-west dimension of the zone of height decrease. A particular case is examined and the behaviour pattern analysed by means of electron density profiles. Height contours of ion density suggest that differences in behaviour at the two stations are partly due to seasonal differences in the height of the F-region. © 1969.