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

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1386
Author(s):  
Robin Wing ◽  
Milena Martic ◽  
Colin Triplett ◽  
Alain Hauchecorne ◽  
Jacques Porteneuve ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Inversion Layer ◽  
Lower Thermosphere ◽  
Breaking Waves ◽  
Meridional Wind ◽  
Weather Forecasts ◽  
Wind Speeds ◽  
Mesosphere And Lower Thermosphere ◽  
Rayleigh Lidar

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.

Wave-induced constituent transport in the middle and upper atmosphere

2021 ◽  
Author(s):  
Maria Vittoria Guarino ◽  
Wuhu Feng ◽  
Chester Gardner ◽  
Daniel Marsh ◽  
John Plane
Keyword(s):  
Gravity Waves ◽  
Lower Thermosphere ◽  
Vertical Mixing ◽  
Breaking Waves ◽  
Transport Processes ◽  
Upper Atmosphere ◽  
Lapse Rate ◽  
Dynamical Structure ◽  
Mesosphere And Lower Thermosphere ◽  
Wave Induced

<div> <p>Atmospheric gravity waves generated in the troposphere by a number of sources (convection, frontogenesis, orography etc.) can travel great vertical distances, propagating upwards to 80 - 120km where they influence the chemical and dynamical structure of the Mesosphere and Lower Thermosphere (MLT).</p> </div><div> <p>Current chemistry-climate models represent gravity waves, and their impact on the temperature and the chemical composition of the atmosphere, by means of parameterizations that take into account the turbulence and the mixing caused by breaking waves but largely neglect the dynamical and chemical constituent transport by vertically propagating non-breaking waves.</p> </div><div> <p>We present initial results from the WAVECHASM (Wave-Induced Transport of Chemically Active Species in the Mesosphere and Lower Thermosphere) project. By making use of a recent novel theoretical approach, where the effective wave diffusivity is expressed as a function of the eddy diffusivity and of the variances of the temperature perturbation and lapse rate fluctuations, the WAVECHASM project aims to incorporate the missing transport processes into global atmospheric chemistry models. We will show here that it is possible to modify the current gravity wave drag parameterization of NCAR’s Whole Atmosphere Community Climate Model (WACCM) to explicitly account for the wave-driven vertical mixing associated with non-breaking gravity waves. This additional source of vertical mixing is expected to induce significant constituent transport in the upper atmosphere.</p> </div>

The coupling of planetary waves, tides and gravity waves in the mesosphere and lower thermosphere

1999 ◽  
Vol 24 (11) ◽  
pp. 1571-1576 ◽  
Author(s):  
P.J.S. Williams ◽  
N.J. Mitchell ◽  
A.G. Beard ◽  
V.St.C. Howells ◽  
H.G. Muller
Keyword(s):  
Gravity Waves ◽  
Lower Thermosphere ◽  
Planetary Waves ◽  
Mesosphere And Lower Thermosphere

The Momentum Budget in the Stratosphere, Mesosphere, and Lower Thermosphere. Part II: The In Situ Generation of Gravity Waves

2018 ◽  
Vol 75 (10) ◽  
pp. 3635-3651 ◽  
Author(s):  
Ryosuke Yasui ◽  
Kaoru Sato ◽  
Yasunobu Miyoshi
Keyword(s):  
Gravity Wave ◽  
Gravity Waves ◽  
Lower Thermosphere ◽  
Shear Instability ◽  
Wave Forcing ◽  
Momentum Budget ◽  
Mesosphere And Lower Thermosphere ◽  
In Situ Generation ◽  
Mlt Region

The contributions of gravity waves to the momentum budget in the mesosphere and lower thermosphere (MLT) is examined using simulation data from the Ground-to-Topside Model of Atmosphere and Ionosphere for Aeronomy (GAIA) whole-atmosphere model. Regardless of the relatively coarse model resolution, gravity waves appear in the MLT region. The resolved gravity waves largely contribute to the MLT momentum budget. A pair of positive and negative Eliassen–Palm flux divergences of the resolved gravity waves are observed in the summer MLT region, suggesting that the resolved gravity waves are likely in situ generated in the MLT region. In the summer MLT region, the mean zonal winds have a strong vertical shear that is likely formed by parameterized gravity wave forcing. The Richardson number sometimes becomes less than a quarter in the strong-shear region, suggesting that the resolved gravity waves are generated by shear instability. In addition, shear instability occurs in the low (middle) latitudes of the summer (winter) MLT region and is associated with diurnal (semidiurnal) migrating tides. Resolved gravity waves are also radiated from these regions. In Part I of this paper, it was shown that Rossby waves in the MLT region are also radiated by the barotropic and/or baroclinic instability formed by parameterized gravity wave forcing. These results strongly suggest that the forcing by gravity waves originating from the lower atmosphere causes the barotropic/baroclinic and shear instabilities in the mesosphere that, respectively, generate Rossby and gravity waves and suggest that the in situ generation and dissipation of these waves play important roles in the momentum budget of the MLT region.

scholarly journals Climatologies and long-term changes in mesospheric wind and wave measurements based on radar observations at high and mid latitudes

2019 ◽  
Vol 37 (5) ◽  
pp. 851-875 ◽  
Author(s):  
Sven Wilhelm ◽  
Gunter Stober ◽  
Peter Brown
Keyword(s):  
Kinetic Energy ◽  
Gravity Waves ◽  
Lower Thermosphere ◽  
Atmospheric Parameters ◽  
Amplitude Response ◽  
Wave Measurements ◽  
Long Term Changes ◽  
The Mean ◽  
Mesosphere And Lower Thermosphere

Abstract. We report on long-term observations of atmospheric parameters in the mesosphere and lower thermosphere (MLT) made over the last 2 decades. Within this study, we show, based on meteor wind measurement, the long-term variability of winds, tides, and kinetic energy of planetary and gravity waves. These measurements were done between the years 2002 and 2018 for the high-latitude location of Andenes (69.3∘ N, 16∘ E) and the mid-latitude locations of Juliusruh (54.6∘ N, 13.4∘ E) and Tavistock (43.3∘ N, 80.8∘ W). While the climatologies for each location show a similar pattern, the locations differ strongly with respect to the altitude and season of several parameters. Our results show annual wind tendencies for Andenes which are toward the south and to the west, with changes of up to 3 m s−1 per decade, while the mid-latitude locations show smaller opposite tendencies to negligible changes. The diurnal tides show nearly no significant long-term changes, while changes for the semidiurnal tides differ regarding altitude. Andenes shows only during winter a tidal weakening above 90 km, while for the Canadian Meteor Orbit Radar (CMOR) an enhancement of the semidiurnal tides during the winter and a weakening during fall occur. Furthermore, the kinetic energy for planetary waves showed strong peak values during winters which also featured the occurrence of sudden stratospheric warming. The influence of the 11-year solar cycle on the winds and tides is presented. The amplitudes of the mean winds exhibit a significant amplitude response for the zonal component below 82 km during summer and from November to December between 84 and 95 km at Andenes and CMOR. The semidiurnal tides (SDTs) show a clear 11-year response at all locations, from October to November.

scholarly journals A comparison of 11-year mesospheric and lower thermospheric winds determined by meteor and MF radar at 69 ° N

2017 ◽  
Vol 35 (4) ◽  
pp. 893-906 ◽  
Author(s):  
Sven Wilhelm ◽  
Gunter Stober ◽  
Jorge L. Chau
Keyword(s):  
Lower Thermosphere ◽  
Meridional Wind ◽  
Correction Factors ◽  
Data Set ◽  
Wind Measurements ◽  
Mesosphere And Lower Thermosphere ◽  
Thermospheric Winds ◽  
Good Agreement ◽  
Mlt Region ◽  
Mf Radar

Abstract. The Andenes Meteor Radar (MR) and the Saura Medium Frequency (MF) Radar are located in northern Norway (69° N, 16° E) and operate continuously to provide wind measurements of the mesosphere and lower thermosphere (MLT) region. We compare the two systems to find potential biases between the radars and combine the data from both systems to enhance altitudinal coverage between 60 and 110 km. The systems have altitudinal overlap between 78 and 100 km at which we compare winds and tides on the basis of hourly winds with 2 km altitude bins. Our results indicate reasonable agreement for the zonal and meridional wind components between 78 and 92 km. An exception to this is the altitude range below 84 km during the summer, at which the correlation decreases. We also compare semidiurnal and diurnal tides according to their amplitudes and phases with good agreement below 90 km for the diurnal and below 96 km for the semidiurnal tides. Based on these findings we have taken the MR data as a reference. By comparing the MF and MR winds within the overlapping region, we have empirically estimated correction factors to be applied to the MF winds. Existing gaps in that data set will be filled with weighted MF data. This weighting is done due to underestimated wind values of the MF compared to the MR, and the resulting correction factors fit to a polynomial function of second degree within the overlapping area. We are therefore able to construct a consistent and homogenous wind from approximately 60 to 110 km.

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

2020 ◽  
Author(s):  
Fabio Vargas ◽  
Jorge L. Chau ◽  
Harikrishnan Charuvil Asokan ◽  
Michael Gerding
Keyword(s):  
Gravity Waves ◽  
Momentum Flux ◽  
Large Scale ◽  
Lower Thermosphere ◽  
Small Scale ◽  
Meteor Radar ◽  
Mean Flow ◽  
Horizontal Scale ◽  
Momentum Fluxes ◽  
Mesosphere And Lower Thermosphere

Abstract. We describe in this study the analysis of small and large horizontal scale gravity waves from datasets composed of images from multiple mesospheric nightglow emissions as well as multistatic specular meteor radar (MSMR) winds collected in early November 2018, during the SIMONe–2018 campaign. These ground-based measurements are supported by temperature and neutral density profiles from TIMED/SABER satellite in orbits near Kühlungsborn, northern Germany (54.1° N, 11.8° E). The scientific goals here include the characterization of gravity waves and their interaction with the mean flow in the mesosphere and lower thermosphere and their relationship to dynamical conditions in the lower and upper atmosphere. We obtain intrinsic parameters of small and large horizontal scale gravity waves and characterize their impact in the mesosphere region via momentum flux and flux divergence estimations. We have verified that a small percent of the detected wave events are responsible for most of the momentum flux measured during the campaign from oscillations seen in the airglow brightness and MSMR winds. From the analysis of small-scale gravity waves in airglow images, we have found wave momentum fluxes ranging from 0.38 to 24.74 m2/s2 (0.88 ± 0.73 m2/s2 on average), with a total of 586.96 m2/s2 (sum over all 362 detected waves). However, small horizontal scale waves with flux > 3 m2/s2 (11 % of the events) transport 50 % of the total measured flux. Likewise, wave events having flux > 10 m2/s2 (2 % of the events) transport 20 % of the total flux. The examination of two large-scale waves seen simultaneously in airglow keograms and MSMR winds revealed relative amplitudes > 35 %, which translates into momentum fluxes of 21.2–29.6 m/s. In terms of gravity wave–mean flow interactions, these high momentum flux waves could cause decelerations of 22–41 m/s/day (small-scale waves) and 38–43 m/s/day (large-scale waves) if breaking or dissipating within short distances in the mesosphere and lower thermosphere region. The dominant large-scale waves might be the result of secondary gravity excited from imbalanced flow in the stratosphere caused by primary wave breaking.

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