General characteristics of the medium-scale gravity waves observed by airglow ground-based imaging over the Antarctic continent

Simultaneous airglow observations were conducted at various Antarctic stations to investigate the general characteristics of medium-scale gravity waves (50–800 km of horizontal wavelength) over the continent during 2022, the most recent year of simultaneous observations. Airglow data were collected from McMurdo (77.8° S, 166.6° E) and Davis (68.5° S, 77.9° E) on the eastern part of the continent, as well as from Rothera (67.5° S, 68.1° W) and the Brazilian Antarctic Station Commandant Ferraz (62.1° S, 58.4° W) on the Antarctic Peninsula. The keogram technique was used to analyze a portion of the wave spectrum that was not previously studied: waves with horizontal wavelengths larger than 100 km. A new analysis methodology, detailed in a companion paper, based on wavelet transform properties, was employed to extract wave parameters such as horizontal wavelength, period, and phase speed. Additionally, data from the WACCM-X model were utilized to calculate intrinsic and vertical parameters and momentum fluxes. Despite differences between the stations, the gravity wave parameters indicated larger wavelengths and phase speeds than those typically observed in tropical and mid-latitude regions. Anisotropy regarding wind filtering was inconclusive; waves propagated in all directions with varying speed ranges, and generally faster than the wind below the observation altitude. Vertical wavelengths ranged flatelly from 10 to 50 km, and momentum fluxes were generally below 20 m2/s2, resulting in a limited energy transport at the observation altitude (~87 km) from these waves.