Gravity wave forcing in the middle atmosphere due to reduced ozone heating during a solar eclipse

1993 ◽  
Vol 98 (D2) ◽  
pp. 3011-3021 ◽  
Author(s):  
David C. Fritts ◽  
Zhangai Luo
Keyword(s):  
Gravity Wave ◽  
Solar Eclipse ◽  
Middle Atmosphere ◽  
Wave Forcing

scholarly journals Forcing mechanisms of the quarterdiurnal tide

2019 ◽  
Author(s):  
Christoph Geißler ◽  
Christoph Jacobi ◽  
Friederike Lilienthal
Keyword(s):  
Gravity Wave ◽  
Middle Atmosphere ◽  
Circulation Model ◽  
Destructive Interference ◽  
Global Circulation Model ◽  
Wave Forcing ◽  
Global Circulation ◽  
Tidal Interactions ◽  
Forcing Mechanisms ◽  
The Individual

Abstract. We used a nonlinear mechanistic global circulation model to analyze the migrating quarterdiurnal tide (QDT) in the middle atmosphere with focus on its possible forcing mechanisms. These are absorption of solar radiation by ozone and water vapor, nonlinear tidal interactions, and gravity wave-tide interactions. We show a climatology of the QDT amplitudes, and we examined the contribution of the different forcing mechanisms on the QDT amplitude. To this end, we first extracted the QDT in the model tendency terms. Then, we separately removed the QDT contribution in different tendency terms. We find that the solar forcing mechanism is the most important one for the QDT, but also the nonlinear and gravity wave forcing mechanism play a role in certain seasons, latitudes and altitudes. Furthermore, destructive interference between the individual forcing mechanisms are observed. Therefore, tidal amplitudes partly become even larger in simulations with removed nonlinear or gravity wave forcing mechanism.

scholarly journals On the Gravity Wave Forcing during the Southern Stratospheric Final Warming in LMDZ

2016 ◽  
Vol 73 (8) ◽  
pp. 3213-3226 ◽  
Author(s):  
Alvaro de la Cámara ◽  
François Lott ◽  
Valérian Jewtoukoff ◽  
Riwal Plougonven ◽  
Albert Hertzog
Keyword(s):  
Gravity Wave ◽  
General Circulation ◽  
Climate Models ◽  
Middle Atmosphere ◽  
Circulation Model ◽  
High Amplitude ◽  
Austral Spring ◽  
Wave Forcing ◽  
Stratospheric Final Warming ◽  
Good Agreement

Abstract The austral stratospheric final warming date is often predicted with substantial delay in several climate models. This systematic error is generally attributed to insufficient parameterized gravity wave (GW) drag in the stratosphere around 60°S. A simulation with a general circulation model [Laboratoire de Météorologie Dynamique zoom model (LMDZ)] with a much less pronounced bias is used to analyze the contribution of the different types of waves to the dynamics of the final warming. For this purpose, the resolved and unresolved wave forcing of the middle atmosphere during the austral spring are examined in LMDZ and reanalysis data, and a good agreement is found between the two datasets. The role of parameterized orographic and nonorographic GWs in LMDZ is further examined, and it is found that orographic and nonorographic GWs contribute evenly to the GW forcing in the stratosphere, unlike in other climate models, where orographic GWs are the main contributor. This result is shown to be in good agreement with GW-resolving operational analysis products. It is demonstrated that the significant contribution of the nonorographic GWs is due to highly intermittent momentum fluxes produced by the source-related parameterizations used in LMDZ, in qualitative agreement with recent observations. This yields sporadic high-amplitude GWs that break in the stratosphere and force the circulation at lower altitudes than more homogeneously distributed nonorographic GW parameterizations do.

scholarly journals Forcing mechanisms of the migrating quarterdiurnal tide

2020 ◽  
Vol 38 (2) ◽  
pp. 527-544 ◽  
Author(s):  
Christoph Geißler ◽  
Christoph Jacobi ◽  
Friederike Lilienthal
Keyword(s):  
Gravity Wave ◽  
Middle Atmosphere ◽  
Lower Thermosphere ◽  
Circulation Model ◽  
Destructive Interference ◽  
Global Circulation Model ◽  
Wave Forcing ◽  
Tidal Interactions ◽  
Forcing Mechanisms ◽  
The Individual

Abstract. We used a nonlinear mechanistic global circulation model to analyze the migrating quarterdiurnal tide (QDT) in the middle atmosphere with focus on its possible forcing mechanisms: the absorption of solar radiation by ozone and water vapor, nonlinear tidal interactions, and gravity wave–tide interactions. We show a climatology of the QDT amplitudes, and we examine the contribution of the different forcing mechanisms to the QDT amplitude. To this end, we first extracted the QDT from the model tendency terms and then removed the respective QDT contribution from the different tendency terms. We find that the solar forcing mechanism is the most important one for the QDT; however, the nonlinear and gravity wave forcing mechanisms also play a role in autumn and winter, particularly at lower and middle latitudes in the mesosphere and lower thermosphere. Furthermore, destructive interference between the individual forcing mechanisms is observed. Therefore, tidal amplitudes become even larger in simulations with the nonlinear or gravity wave forcing mechanisms removed.

scholarly journals Simulating influences of QBO phases and orographic gravity wave forcing on planetary waves in the middle atmosphere

2015 ◽  
Vol 67 (1) ◽  
Author(s):  
Nikolai M. Gavrilov ◽  
Andrej V. Koval ◽  
Alexander I. Pogoreltsev ◽  
Elena N. Savenkova
Keyword(s):  
Gravity Wave ◽  
Middle Atmosphere ◽  
Planetary Waves ◽  
Wave Forcing

Self-Acceleration in the Parameterization of Orographic Gravity Wave Drag

2010 ◽  
Vol 67 (8) ◽  
pp. 2537-2546 ◽  
Author(s):  
John F. Scinocca ◽  
Bruce R. Sutherland
Keyword(s):  
Gravity Wave ◽  
Middle Atmosphere ◽  
Wave Train ◽  
Leading Edge ◽  
Wave Theory ◽  
Wave Drag ◽  
Tuning Parameter ◽  
Mean Flow ◽  
Propagating Waves ◽  
The Impact

Abstract A new effect related to the evaluation of momentum deposition in conventional parameterizations of orographic gravity wave drag (GWD) is considered. The effect takes the form of an adjustment to the basic-state wind about which steady-state wave solutions are constructed. The adjustment is conservative and follows from wave–mean flow theory associated with wave transience at the leading edge of the wave train, which sets up the steady solution assumed in such parameterizations. This has been referred to as “self-acceleration” and it is shown to induce a systematic lowering of the elevation of momentum deposition, which depends quadratically on the amplitude of the wave. An expression for the leading-order impact of self-acceleration is derived in terms of a reduction of the critical inverse Froude number Fc, which determines the onset of wave breaking for upwardly propagating waves in orographic GWD schemes. In such schemes Fc is a central tuning parameter and typical values are generally smaller than anticipated from conventional wave theory. Here it is suggested that self-acceleration may provide some of the explanation for why such small values of Fc are required. The impact of Fc on present-day climate is illustrated by simulations of the Canadian Middle Atmosphere Model.

Atmospheric gravity wave production for the solar eclipse of October 23, 1976

Nature ◽  
1976 ◽  
Vol 264 (5585) ◽  
pp. 420-421 ◽  
Author(s):  
TOM BEER ◽  
G. L. GOODWIN ◽  
G. J. HOBSON
Keyword(s):  
Gravity Wave ◽  
Solar Eclipse ◽  
Atmospheric Gravity Wave ◽  
Atmospheric Gravity

scholarly journals The nonlinear effects on the characteristics of gravity wave packets: dispersion and polarization relations

2000 ◽  
Vol 18 (10) ◽  
pp. 1316-1324 ◽  
Author(s):  
S.-D. Zhang ◽  
F. Yi ◽  
J.-F. Wang
Keyword(s):  
Gravity Wave ◽  
Gravity Waves ◽  
Middle Atmosphere ◽  
Wave Packets ◽  
Nonlinear Effects ◽  
Wave Theory ◽  
Nonlinear Propagation ◽  
Waves And Tides ◽  
Time Variations ◽  
Isothermal Atmosphere

Abstract. By analyzing the results of the numerical simulations of nonlinear propagation of three Gaussian gravity-wave packets in isothermal atmosphere individually, the nonlinear effects on the characteristics of gravity waves are studied quantitatively. The analyses show that during the nonlinear propagation of gravity wave packets the mean flows are accelerated and the vertical wavelengths show clear reduction due to nonlinearity. On the other hand, though nonlinear effects exist, the time variations of the frequencies of gravity wave packets are close to those derived from the dispersion relation and the amplitude and phase relations of wave-associated disturbance components are consistent with the predictions of the polarization relation of gravity waves. This indicates that the dispersion and polarization relations based on the linear gravity wave theory can be applied extensively in the nonlinear region.Key words: Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides)

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