Latitudinal and seasonal variations in the night airglow

A four-color turret photometer has been used for shipboard observations of the night airglow and the aurora. Zenith observations have been obtained during 1962 close to the 70°W meridian from the northern auroral zone to the antarctic pack ice. Most of the observations were taken during the southern winter. Maximums in the [O I] 5577 A intensity were found near 30–40°N and 40°S, the southern hemisphere level being generally lower than that in the northern hemisphere. The [O I] 6300 A latitudinal variation was similar to that of [O I] 5577 A except that maximums in the latitudinal distribution were found near 15° geomagnetic north and south latitudes. In contrast with the [O I] emissions, the sodium group (Na D doublet and OH bands near 5893 A) generally increased to the south with maximums near 20–30°N and 40–50°S geographic latitude. The total 5340 A background increased from north to south. When the integrated starlight and zodiacal light components were subtracted from the total background, the resultant terrestrial component showed a pronounced minimum at low latitudes and apparent symmetry about the geomagnetic equator.