Atomic emission in the ultraviolet nightglow

An observation of the ultraviolet nightglow between 2670 A and 3040 A was conducted over White Sands Missile Range on October 22, 1984, at 0020 hours LST during the Orionids meteor shower. A 1/4-meter UV spectrometer operating at 3.5 A resolution viewed the earth's limb at tangent heights between 90 km and 110 km for 120 seconds. By inverting the observed limb intensities, a total zenith intensity of 1.4 kR is inferred for the Herzberg I system. Excess emission above the Herzberg I (7,3) band at 2852 A is identified as the Mg I resonance line. The intensity ratio of the Herzberg I band system to the 2972 A line from O(1S) was less than that predicted from the accepted O(1S) branching ratio and acceptable ratios of Herzberg I to 5577 A emissions. Arguments supporting the identification of the Herzberg III band system are also advanced.