Fig. 6From: Enhancement of equatorial OI(1D) emissions at midnightCombined occurrence rates of the three types of brightness from all the orbits during the 7 seasons: a for the region between the 0° and 150° longitudes (Zone-N); b for the region between the − 75° and − 15° longitudes (Zone-S). Single-peaked events are in red, double-peaked events are in blue, and no-peak events are in green. The numbers at the top of bar are event numbersBack to article page