Gravity Wave Breaking Associated with Mesospheric Inversion Layers as Measured by the Ship-Borne BEM Monge Lidar and ICON-MIGHTI

During a recent 2020 campaign, the Rayleigh lidar aboard the Bâtiment d’Essais et de Mesures (BEM) Monge conducted high-resolution temperature measurements of the upper Mesosphere and Lower Thermosphere (MLT). These measurements were used to conduct the first validation of ICON-MIGHTI temperatures by Rayleigh lidar. A double Mesospheric Inversion Layer (MIL) as well as shorter-period gravity waves was observed. Zonal and meridional wind speeds were obtained from locally launched radiosondes and the newly launched ICON satellite as well as from the European Centre for Medium-Range Weather Forecasts (ECMWF-ERA5) reanalysis. These three datasets allowed us to see the evolution of the winds in response to the forcing from the MIL and gravity waves. The wavelet analysis of a case study suggests that the wave energy was dissipated in small, intense, transient instabilities about a given wavenumber in addition to via a broad spectrum of breaking waves. This article will also detail the recent hardware advances of the Monge lidar that have allowed for the measurement of MILs and gravity waves at a resolution of 5 min with an effective vertical resolution of 926 m.

Rayleigh Lidar Observations and Comparisons with TIMED/SABER of Typical Case Studies in Beijing (40.5° N, 116.2° E), China

Based on 139 nights of observational data of the Rayleigh lidar site in Beijing, China (40.5° N, 116.2° E), typical lower MIL cases and their temperature inversion evolution process were reported and compared with the SABER data from the same time. Meanwhile, the seasonal distribution of lower MIL cases over North China was also statistically analyzed. The average inversion temperature of the low MIL is 23.4 K, and the average layer thickness is 4.78 km with an average MIL bottom altitude of 68.2 km. Meanwhile, 65% of the MIL propagates vertically, most of which goes downward. These results show the temperature behavior properties of the lower MIL over North China, which may be helpful for us to further understand middle atmosphere chemical and dynamics processes.

Gravity wave analysis using OH airglow and Rayleigh lidar at the Haute-Provence observatory

<div> <div> <div> <p>In the frame of the European H2020 project ARISE, a short wave infrared (SWIR) InGaAs camera has been operated at the Haute-Provence Observatory. This camera allows continuous observations during clear-sky nighttime of the OH airglow layer centered at 87 km. These observations were collocated with Rayleigh lidar measurements providing vertical temperature profiles from the lower stratosphere to the altitude of the OH layer around the mesopause. Spectral analysis of OH images and temperature fluctuations allows us to identify and characterize gravity waves, their activity observed from the OH camera and the lidar, appear to be modified with the presence of a temperature inversion described by this one.</p> </div> </div> </div>

Atmospheric Density and Temperature Vertical Profile Retrieval for Flight-Tests with a Rayleigh Lidar On-Board the French Advanced Test Range Ship Monge

The Advanced Test Range Ship Monge (ATRSM) is dedicated to in-flight measurements during the re-entry phase of ballistic missiles test flights. Atmospheric density measurements from 15 to 110 km are provided using one of the world’s largest Rayleigh lidars. This lidar is the culmination of three decades of French research experience in lidar technologies, developed within the framework of the global Network for Detection of Atmospheric and Climate Changes (NDACC), and opens opportunities for high resolution Rayleigh lidar studies above 90 km. The military objective of the ATRSM project is to provide near real time estimates of the atmospheric relative density profile, with an error budget of less than 10% at 90 km altitude, given a temporal integration of 15 min and a vertical resolution of 500 m. To achieve this aim we have developed a unique lidar system which exploits six laser transmitters and a constellation of eight receiving telescopes which maximises the lidar power-aperture product. This system includes a mix of standard commercially available optical components and electronics as well as some innovative technical solutions. We have provided a detailed assessment of some of the more unique aspects of the ATRSM lidar.

Retrieval of intrinsic mesospheric gravity wave parameters using lidar and airglow temperature and meteor radar wind data

We analyse gravity waves in the upper-mesosphere, lower-thermosphere region from high-resolution temperature variations measured by the Rayleigh lidar and OH temperature mapper. From this combination of instruments, aided by meteor radar wind data, the full set of ground-relative and intrinsic gravity wave parameters are derived by means of the novel WAPITI (Wavelet Analysis and Phase line IdenTIfication) method. This WAPITI tool decomposes the gravity wave field into its spectral component while preserving the temporal resolution, allowing us to identify and study the evolution of gravity wave packets in the varying backgrounds. We describe WAPITI and demonstrate its capabilities for the large-amplitude gravity wave event on 16–17 December 2015 observed at Sodankylä, Finland, during the GW-LCYCLE-II (Gravity Wave Life Cycle Experiment) field campaign. We present horizontal and vertical wavelengths, phase velocities, propagation directions and intrinsic periods including uncertainties. The results are discussed for three main spectral regions, representing small-, medium- and large-period gravity waves. We observe a complex superposition of gravity waves at different scales, partly generated by gravity wave breaking, evolving in accordance with a vertically and presumably also horizontally sheared wind.

Retrieval of intrinsic mesospheric gravity wave parameters using lidar and airglow temperature and meteor radar wind data

We analyze gravity waves in the mesosphere, lower thermosphere region from high-resolution temperature variation measured by Rayleigh lidar and OH temperature mapper. From this combination of instruments, aided by meteor radar wind data, the full set of ground-relative and intrinsic gravity wave parameters are derived by means of the novel WAPITI method. This Wavelet Analysis and Phase line IdenTIfication tool decomposes the gravity wave field into its spectral components while preserving the temporal resolution, allowing us to identify and study the evolution of gravity wave packets in the varying background. We describe WAPITI and demonstrate its capabilities for the large-amplitude gravity wave event on 16/17 December 2015 observed at Sodankylä, Finland, during the GW-LCYCLE-II field campaign. We present horizontal and vertical wavelengths, phase velocities, propagation directions and intrinsic periods including uncertainties. The results are discussed for three main spectral regions, representing short, medium and long-period gravity waves. We observe a complex superposition of gravity waves at different scales, partly generated by gravity wave breaking, evolving in accordance with a vertically and presumably also horizontally sheared wind.