Seasonal variations in the correlation of atomic-oxygen 557.7-nm emission with solar activity and in long-term trend

For mid-latitude conditions, the correlation coefficient between the green atomic-oxygen emission intensity and solar activity as well as the long-ter m trend vary over a year. The correlation with solar activity is strongest in spring and weakens sharply in mid-summer. After an increase near autumna l equinox, it again weakens in pre-winter months, when an autumn intensity peak is observed. The effect of the long-term variations is greatest in sum mer. When the correlation weakens, the atomic-oxygen layer sinks, which is confirmed by the behavior of similar parameters for the sodium and hydroxyl emissions. A significant change in the height profile of atomic-oxygen den sity appears to be mainly responsible for the peculiarities of the seasonal emission variations in the magnetopause region.