Investigation on Spectral Characteristics of Gravity Waves in the MLT Using Lidar Observations at Andes

Abstract

It is known for decades that gravity waves (GWs) have a substantial influence on the mean circulation and thermal structure of the middle and upper atmosphere because they transport energy and momentum from the lower atmosphere and deposit them into the middle and upper atmosphere due to the instability (Fritts & Alexander, 2003;Holton, 1982). As GWs generated in the lower atmosphere propagate upward, their amplitudes increase exponentially with altitude because of the decrease of atmospheric density. When the amplitude reaches the critical value, GWs break up as a result of convective or dynamic instability or critical level filtering and then release energy and momentum to the background flow, which is regarded as wave saturation and dissipation process (Hickey et al., 2003;Lindzen, 1981).As a delicate method, hodograph technique is extensively utilized to extract the predominant inertia-gravity wave (IGW) from the observational profiles of radiosonde (

A Statistical Investigation of Inertia Gravity Wave Activity Based on MST Radar Observations at Xianghe (116.9°E, 39.8°N), China

“…In observational studies, the waves are widely investigated over global sites by choosing different height ranges, and each instrument has its preferences in capturing different scale waves due to instrumental filtering. Even so, radiosonde, radar, and lidar measurements show that IGWs have typical horizontal wavelengths of tens to thousands of kilometers, vertical wavelengths of a few to tens of kilometers, and intrinsic frequency mainly between $$f$$ and $$5f$$ (Cai et al., 2014; Huang et al., 2018, 2021; Nath et al., 2009; Suzuki et al., 2013; Vincent & Alexander, 2000; Wang et al., 2005; Yamamori & Sato, 2006; Zhang & Yi, 2005, 2007; J. Zhao et al., 2017). Hence, the spatial and temporal scales of the IGWs observed by the MST radar are in the ranges of typical IGW scales.…”

“…Relative to routine radiosonde release twice a day, lidars can obtain temperature and wind in the mesosphere and lower thermosphere (MLT) with fine temporal resolutions and long‐term monitoring, which offer opportunities to examine dynamic processes associated with GWs in detailed (e.g., Cai et al., 2014; Chen et al., 2013; Huang et al., 2021; Lu et al., 2015; Strelnikova, et al., 2020; Yuan et al., 2016). Lidars can even measure gravity waves in the E‐F regions (e.g., Chu et al., 2011, 2020).…”

Stability Characteristics of the Mesopause Region Above the Andes

“…The measurements of temperature and winds used for stability analysis are acquired with the Na lidar at Andes Lidar Observatory located at Cerro Pachón, Chile (30.3°S, 70.7°W). The lidar's large power aperture product (0.66 Wm −2 ), reliable solid state laser, and efficient receiver optics (Liu et al., 2016), combined with the high elevation site in the Andes with year around clear sky, make it feasible to acquire many nights of measurements at high temporal and spatial resolutions (Guo & Liu, 2021; Guo et al., 2017; Huang et al., 2021). In a normal operation mode, the laser beam was pointed toward zenith (Z), and 20° off zenith toward east (E) and south (S) in zenith‐south‐zenith‐east sequence with typically 60‐s interval at each direction.…”

Validation of Multistatic Meteor Radar Analysis Using Modeled Mesospheric Dynamics: An Assessment of the Reliability of Gradients and Vertical Velocities

“…Continuous observations of the MLT have always been a difficult task. Historically, a few ground‐based instruments like lidars, optical imagers, and different radars have contributed to further the understanding of MLT dynamics (e.g., Chen et al., 2016; Gerding et al., 2021; Hecht et al., 2010; Hibbins et al., 2007; Hoffmann et al., 2010; Huang et al., 2021; Larsen, 2004; Liu et al., 2020; Lübken et al., 2011; Murphy et al., 2009; Nakamura et al., 2001).…”