High resolution horizontal wave number spectra of mesospheric wave perturbations observed during the 21 October triangular flight of ALOHA‐93

On 21 October 1993 during ALOHA‐93 the NCAR Electra flew a triangular path to the northwest of Maui. To improve the horizontal resolution of the Na lidar and OH imager, the aircraft cruising speed was reduced to an average of ∼135 m/s. The lidar and imager observations are used to study the high horizontal wave number (k) region of mesospheric wave perturbation spectra. The relative atmospheric density spectrum inferred from the Na lidar data is well approximated by the k^−1.3 power‐law over the complete wave number range from k = 2π/(400 km) to 2π/(2 km). The observed spectrum shows no evidence of the index change near k = m_* predicted by the separable gravity wave model of Gardner et al. [1993], where m_* is the characteristic vertical wave number. The OH intensity spectra computed across and along the flight track, as well as the Na abundance spectrum, are inconsistent with both the separable gravity wave model [Gardner et al., 1993] and scale‐independent diffusive filtering theory [Gardner, 1994]. Existing models of Na abundance and OH intensity fluctuations are based on linear perturbation theory and may not be valid because they do not include nonlinear effects.