NEAR-INFRARED IMAGING OF HYDROXYL WAVE STRUCTURE OVER AN OCEAN SITE AT LOW LATITUDES

Coordinated observations of wave structure in the near infrared hydroxyl (OH) nightglow emission have been made from Maui, Hawaii using a suite of narrow angle and all-sky TV cameras. Two sets of data were obtained, the first in conjunction with the ALOHA-90 campaign and the second during the subsequent new moon period. Well formed, short period (< 20 min) wave patterns of comparable morphology, dynamics and abundance to those regularly imaged from mid-latitude mountain sites were detected on several occasions. Although the Hawaiian islands comprise several high volcanic peaks, the patterns were not consistent with gravity waves generated by the interaction of strong winds with the local island topography. This suggests that other mid-latitude wave patterns may also not be of mountain origin. The wave patterns imaged during ALOHA-90 were of significantly lower contrast than those detected later. This effect may be related to changes in the characteristics of the middle atmosphere that occur shortly after the spring equinox.