Persistent, dominant, and large‐amplitude gravity waves with 3–10 h periods and vertical wavelengths ~20–30 km are observed in temperatures from the stratosphere to lower thermosphere with an Fe Boltzmann lidar at McMurdo, Antarctica. These waves exhibit characteristics of inertia‐gravity waves in case studies, yet they are extremely persistent and have been present during every lidar observation. We characterize these 3–10 h waves in the mesosphere and lower thermosphere using lidar temperature data in June from 2011 to 2015. A new method is applied to identify the major wave events from every lidar run longer than 12 h. A continuous 65 h lidar run on 28–30 June 2014 exhibits a 7.5 h wave spanning ~60 h, and 6.5 h and 3.4 h waves spanning 40 and 45 h, respectively. Over the course of 5 years, 323 h of data in June reveal that the major wave periods occur in several groups centered from ~3.5 to 7.5 h, with vertical phase speeds of 0.8–2 m/s. These 3–10 h waves possess more than half of the spectral energy for ~93% of the time. A rigorous prewhitening, postcoloring technique is introduced for frequency power spectra investigation. The resulting spectral slopes are unusually steep (−2.7) below ~100 km but gradually become shallower with increasing altitude, reaching about −1.6 at 110 km. Two‐dimensional fast Fourier transform spectra confirm that these waves have a uniform dominant vertical wavelength of 20–30 km across periods of 3.5–10 h. These statistical features shed light on the wave source and pave the way for future research.

Five years of atmospheric temperature data, collected with an Fe Boltzmann lidar by the University of Colorado group from 2011 to 2015 at Arrival Heights, are used to characterize the vertical wavelengths, periods, vertical phase speeds, frequency spectra, and vertical wave number spectra of stratospheric gravity waves from 30 to 50 km altitudes. Over 1000 dominant gravity wave events are identified from the data. The seasonal spectral distributions of vertical wavelengths, periods, and vertical phase speeds in summer, winter, and spring/fall are found obeying a lognormal distribution. Both the downward and upward phase progression gravity waves are observed by the lidar, and the fractions of gravity waves with downward phase progression increase from summer ~59% to winter ~70%. The seasonal and monthly mean vertical wavelengths and periods exhibit clear seasonal cycles with vertical wavelength growing from summer ~5.5 km to winter ~8.5 km, and period increasing from summer ~4.5 h to winter ~6 h. Statistically significant linear correlations are found between the monthly mean vertical wavelengths/periods and the mean zonal wind velocities from 30 to 50 km. Assuming horizontal phase speeds independent of month, the monthly mean horizontal wavelengths, intrinsic periods, and group velocities are estimated for stratospheric gravity waves. The slopes of wave frequency spectra change from −1.9 at 30–60 km to −1.45 around 60–65 km. The vertical wave number spectra show the power spectral density at vertical wavelengths of 5–20 km decreasing from winter maximum to summer minimum. Several aforementioned features are observed for the first time in Antarctica.

This study presents the first coincident observation of inertia‐gravity waves (IGWs) by lidar and radar in the Antarctic mesopause region. This is also the first known observation of two simultaneous IGWs at the same location. An Fe Boltzmann lidar at Arrival Heights (77.8°S, 166.7°E) provides high‐resolution temperature data, and a co‐located MF radar provides wind data. On 29 June 2011, coherent wave structures are observed in both the Fe lidar temperature and MF radar winds. Two dominant waves are determined from the temperature data with apparent periods of 7.7 ± 0.2 and 5.0 ± 0.1 h and vertical wavelengths of 22 ± 2 and 23 ± 2 km, respectively. The simultaneous measurements of temperature and wind allow the intrinsic wave properties to be derived from hodograph analyses unambiguously. The analysis shows that the longer‐period wave propagates northward with an azimuth of θ = 11° ± 5° clockwise from north. This wave has a horizontal wavelength of λ_h = 2.2 ± 0.2 × 10³ km and an intrinsic period of τ_I = 7.9 ± 0.3 h. The intrinsic horizontal phase speed (C_Ih) for this wave is 80 ± 4 m/s, while the horizontal and vertical group velocities (C_gh and C_gz) are 48 ± 3 m/s and 0.5 ± 0.1 m/s, respectively. The shorter‐period wave has τ_I = 4.5 ± 0.3 h and θ = 100° ± 4° with λ_h = 1.1 ± 0.1 × 10³ km and C_Ih = 68 ± 5 m/s. Its group velocities are C_gh = 58 ± 5 m/s and C_gz = 1.1 ± 0.1 m/s. Therefore, both waves propagate with very shallow elevation angles from the horizon (ϕ = 0.6° ± 0.1° and ϕ = 1.1° ± 0.1° for the longer‐ and shorter‐period waves, respectively) but originate from different sources. Our analysis suggests that the longer‐period IGW most likely originates from the stratosphere in a region of unbalanced flow.

We report the first characterization of potential energy densities and vertical wave number spectra of Antarctic gravity waves (GWs) from 35 to 105 km, derived from Fe lidar temperature measurements at McMurdo (77.8°S, 166.7°E) in 2011–2013 winters. For GWs with periods of 2–10 h, the potential energy density per unit volume (E_pv) decreases by 2 orders of magnitude from 35 to 105 km, while that per unit mass (E_pm) increases from several to hundreds of J/kg. E_pm increases with a mean scale height of ~10.4 km in the Rayleigh region (35–65 km) and of ~13.2 km in the Fe region (81–105 km), and of particular interest is the inferred severe dissipation in between (65–81 km). Overall, the vertical evolutions of E_pv and E_pm indicate considerable wave energy loss from the stratosphere to the lower thermosphere. The vertical wave number spectra exhibit power law forms for vertical wavelengths λ_z < ~10 km. The mean spectral slope in the spectral range of 2–10 km is about −2.55 and −2.26 in the Rayleigh and Fe regions with standard deviations of 0.36 and 0.38, respectively. Large variations in the power spectral densities (PSDs) are seen for λ_z > 10 km in 35–60 km. PSDs increase by 1 order of magnitude from the stratosphere to the lower thermosphere. Using higher temporal resolution data to include 0.5–2 h waves increase E_pm by ~25–45% and increase PSDs of 2–5 km waves by a factor of 2 and of >10 km waves by less than 50%.