Growth Rate of Gravity Wave Amplitudes Observed in Sodium Lidar Density Profiles and Nightglow Image Data

Abstract

Amplitude growth rates of quasi-monochromatic gravity waves were estimated and compared from multiple instrument measurements carried out in Brazil. Gravity wave parameters, such as the wave amplitude and growth rate in distinct altitudes, were derived from sodium lidar density and nightglow all-sky images. Lidar observations were carried out in São Jose dos Campos (23 ∘ S, 46 ∘ W) from 1994 to 2004, while all-sky imagery of multiple airglow layers was conducted in Cachoeira Paulista (23 ∘ S, 45 ∘ W) from 1999–2000 and 2004–2005. We have found that most of the measured amplitude growth rates indicate dissipative behavior for gravity waves identified in both lidar profiles and airglow image datasets. Only a small fraction of the observed wave events (4% imager; 9% lidar) are nondissipative (freely propagating waves). Our findings also show that imager waves are strongly dissipated within the mesosphere and lower thermosphere region (MLT), decaying in amplitude in short distances (<12 km), while lidar waves tend to maintain a constant amplitude within that region. Part of the observed waves (16% imager; 36% lidar) showed unchanging amplitude with altitude (saturated waves). About 51.6% of the imager waves present strong attenuation (overdamped waves) in contrast with 9% of lidar waves. The general saturated or damped behavior is consistent with diffusive filtering processes imposing limits to amplitude growth rates of the observed gravity waves.

Mesospheric gravity wave activity estimated via airglow imagery, multistatic meteor radar, and SABER data taken during the SIMONe–2018 campaign

“…Ern et al (2011) shows absolute F M values of ∼ 10 −3.9 Pa at 50 km altitude and ∼ 10 −4.3 Pa at 70 km altitude in the Northern Hemisphere in January for latitudes/longitudes near the Kühlungsborn observatory, evidencing momentum flux deposition in the middle atmosphere. Thus, it is likely that the small-scale waves observed here mostly dissipate as they travel through the MLT, in agreement with Vargas et al (2019). In another flux estimation study using airglow imagery of gravity waves, Vargas et al (2009) revealed F M ranging from ∼ 1.5 to ∼ 4.5 m 2 s −2 , while radar measurements of, e.g, Yuan and Fritts (1989) estimated F M = 5-15 m 2 s −2 .…”

“…According to Vargas et al (2019), only a minority of waves seen in the airglow (∼ 5 %) are in non-dissipating regimes. Vargas et al (2019) also show that the majority of the gravity waves present strong dissipation and transfer momentum flux to the main flow within a distance of two atmospherescale heights (12-14 km). Thus, the large F M waves discussed here are likely to present dissipative or breaking characteristics given their larger amplitudes.…”

“…Thus, the parameters shown correspond to intrinsic properties of the waves. We have calculated the error bars for the parameters of each wave event measured using the methodology in Vargas et al (2019). The average error of each parameter is shown in their respective charts in Fig.…”

Observations of Quasi-Periodic Electric Field Disturbances in the E Region before and during the Equatorial Plasma Bubble

“…The equatorial E region is also the part of the Mesosphere-Lower-Thermosphere (MLT) region of the atmosphere that hosts robust wave activities and sporadic E layer activities from the tidal wave modes and gravity wave modes [19][20][21]. The radar observations reveal FAI-E with periodic-EDs from these modes before the occurrence of EPBs [22,23].…”

Special Issue Editorial: Atmospheric Airglow—Recent Advances in Observations, Experimentations, and Modeling

“…It is suggested that averages of wind be used in short-day intervals for difficult airglow observational conditions and that hourly winds be used for analyses of specific wave filtering. Vargas et al [6] presented their analysis of AGW observations made by a Na lidar and an all-sky imager in the Brazilian sector. Amplitude growth rates of gravity waves were estimated and compared from multiple instrument measurements.…”