CONCURRENT OBSERVATIONS OF AURORAL ACTIVITY AND A LARGE SPORADIC SODIUM LAYER EVENT DURING ANLC-93

Prominent sporadic sodium (Na-s) layers, apparently associated with in tense auroral activity, were observed during the 1993 Arctic Noctiluce nt Cloud Campaign (ANLC-93) with an airborne sodium lidar on the Augus t 6 flight near 51 degrees N latitude. The peak density of the Na-s la yer reached 74,500 cm(-3). The zonal extent of the Na-s layers exceede d 1600 km. Strong auroral emissions were recorded with an all-sky imag er on the aircraft. A Michelson Interferometer was used to measure the intensity of OH nightglow between 85-90 km. OH rotational temperature exhibited no obvious correlation with the Na-s layer peak density nea r 94 km. The data Suggest a connection between the Na-s layers and aur oral electron precipitations. The data also support the conjecture tha t dust and smoke particles may play a crucial role in the Na-s layer f ormation.