Quasi‐Biennial Oscillation of Short‐Period Planetary Waves and Polar Night Jet in Winter Antarctica Observed in SABER and MERRA‐2 and Mechanism Study With a Quasi‐Geostrophic Model

Abstract Evidence of the solar cycle in stratospheric polar temperature rests on a connection to the quasi-biennial oscillation (QBO) of equatorial wind. New evidence reported here establishes a mechanism for how the solar signature in polar temperature follows from the QBO, which itself is shown to vary with the solar cycle. Equatorial westerlies below 30 mb vary systematically with solar activity, as do equatorial easterlies above 30 mb. Changes in their duration introduce a systematic drift into the QBO's phase relative to winter months, when the polar vortex is sensitive to equatorial wind. Corresponding changes in the polar-night vortex are consistent with the solar signature observed in wintertime records of polar temperature that have been stratified according to the QBO.

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Constraints on Wave Drag Parameterization Schemes for Simulating the Quasi-Biennial Oscillation. Part I: Gravity Wave Forcing

Journal of the Atmospheric Sciences ◽

10.1175/jas3616.1 ◽

2005 ◽

Vol 62 (12) ◽

pp. 4178-4195 ◽

Cited By ~ 14

Author(s):

Lucy J. Campbell ◽

Theodore G. Shepherd

Keyword(s):

Gravity Wave ◽

Zonal Wind ◽

Shear Zones ◽

Wave Drag ◽

Planetary Waves ◽

Vertical Diffusion ◽

Quasi Biennial Oscillation ◽

Parameterization Schemes ◽

Downward Propagation ◽

Biennial Oscillation

Abstract Parameterization schemes for the drag due to atmospheric gravity waves are discussed and compared in the context of a simple one-dimensional model of the quasi-biennial oscillation (QBO). A number of fundamental issues are examined in detail, with the goal of providing a better understanding of the mechanism by which gravity wave drag can produce an equatorial zonal wind oscillation. The gravity wave–driven QBOs are compared with those obtained from a parameterization of equatorial planetary waves. In all gravity wave cases, it is seen that the inclusion of vertical diffusion is crucial for the descent of the shear zones and the development of the QBO. An important difference between the schemes for the two types of waves is that in the case of equatorial planetary waves, vertical diffusion is needed only at the lowest levels, while for the gravity wave drag schemes it must be included at all levels. The question of whether there is downward propagation of influence in the simulated QBOs is addressed. In the gravity wave drag schemes, the evolution of the wind at a given level depends on the wind above, as well as on the wind below. This is in contrast to the parameterization for the equatorial planetary waves in which there is downward propagation of phase only. The stability of a zero-wind initial state is examined, and it is determined that a small perturbation to such a state will amplify with time to the extent that a zonal wind oscillation is permitted.

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On the origin of the mesospheric quasi-stationary planetary waves in the unusual Arctic winter 2015/2016

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-4803-2018 ◽

2018 ◽

Vol 18 (7) ◽

pp. 4803-4815 ◽

Cited By ~ 8

Author(s):

Vivien Matthias ◽

Manfred Ern

Keyword(s):

Planetary Wave ◽

Polar Night ◽

Quasi Biennial Oscillation ◽

Model Studies ◽

Broadband Emission ◽

Variable Gravity ◽

Stationary Planetary Wave ◽

Second Period ◽

Biennial Oscillation

Abstract. The midwinter 2015/2016 was characterized by an unusually strong polar night jet (PNJ) and extraordinarily large stationary planetary wave (SPW) amplitudes in the subtropical mesosphere. The aim of this study is, therefore, to find the origin of these mesospheric SPWs in the midwinter 2015/2016 study period. The study duration is split into two periods: the first period runs from late December 2015 until early January 2016 (Period I), and the second period from early January until mid-January 2016 (Period II). While the SPW 1 dominates in the subtropical mesosphere in Period I, it is the SPW 2 that dominates in Period II. There are three possibilities explaining how SPWs can occur in the mesosphere: (1) they propagate upward from the stratosphere, (2) they are generated in situ by longitudinally variable gravity wave (GW) drag, or (3) they are generated in situ by barotropic and/or baroclinic instabilities. Using global satellite observations from the Microwave Limb Sounder (MLS) and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) the origin of the mesospheric SPWs is investigated for both time periods. We find that due to the strong PNJ the SPWs were not able to propagate upward into the mesosphere northward of 50∘ N but were deflected upward and equatorward into the subtropical mesosphere. We show that the SPWs observed in the subtropical mesosphere are the same SPWs as in the mid-latitudinal stratosphere. Simultaneously, we find evidence that the mesospheric SPWs in polar latitudes were generated in situ by longitudinally variable GW drag and that there is a mixture of in situ generation by longitudinally variable GW drag and by instabilities at mid-latitudes. Our results, based on observations, show that the abovementioned three mechanisms can act at the same time which confirms earlier model studies. Additionally, the possible contribution from, or impact of, unusually strong SPWs in the subtropical mesosphere to the disruption of the quasi-biennial oscillation (QBO) in the same winter is discussed.

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Climatic variability of the stratosphere-troposphere coupling during the last decades

Вестник КРАУНЦ. Физико-математические науки ◽

10.26117/2079-6641-2021-37-4-159-170 ◽

2021 ◽

pp. 159-170

Author(s):

К.А. Диденко ◽

Т.С. Ермакова ◽

А.И. Погорельцев ◽

Е.В. Ракушина

Keyword(s):

East Asia ◽

Temporal Variability ◽

Linear Trend ◽

Climatic Variability ◽

Three Dimensional ◽

Wave Activity ◽

Planetary Waves ◽

Quasi Biennial Oscillation ◽

Biennial Oscillation ◽

Dimensional Wave

В данной работе показано, как изменялось взаимодействие между тропосферой и стратосферой в последние десятилетия. Также оценено влияние таких явлений, как квазидвухлетнее колебание (КДК) на данное взаимодействие. Для этого было проанализировано распространение планетарных волн в атмосфере с использованием трехмерных потоков волновой активности, показана временная изменчивость потоков и линейный тренд. Кроме того, была оценена реакция тропосферы над Сибирью и Восточной Азией на КДК. The study of the variability of stratosphere-troposphere coupling during the last decades is considered. The influence of such phenomena as quasi-biennial oscillation (QBO) on this interaction was also estimated. For this, the propagation of planetary waves in the atmosphere was analyzed using three-dimensional wave activity fluxes. The temporal variability of fluxes and a linear trend was shown. In addition, the response of the troposphere over Siberia and East Asia to the QBO was assessed.

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Constraints on Wave Drag Parameterization Schemes for Simulating the Quasi-Biennial Oscillation. Part II: Combined Effects of Gravity Waves and Equatorial Planetary Waves

Journal of the Atmospheric Sciences ◽

10.1175/jas3617.1 ◽

2005 ◽

Vol 62 (12) ◽

pp. 4196-4205 ◽

Cited By ~ 8

Author(s):

Lucy J. Campbell ◽

Theodore G. Shepherd

Keyword(s):

Gravity Wave ◽

Gravity Waves ◽

General Circulation ◽

Planetary Wave ◽

General Circulation Models ◽

Wave Drag ◽

Planetary Waves ◽

Small Contribution ◽

Quasi Biennial Oscillation ◽

Biennial Oscillation

Abstract This study examines the effect of combining equatorial planetary wave drag and gravity wave drag in a one-dimensional zonal mean model of the quasi-biennial oscillation (QBO). Several different combinations of planetary wave and gravity wave drag schemes are considered in the investigations, with the aim being to assess which aspects of the different schemes affect the nature of the modeled QBO. Results show that it is possible to generate a realistic-looking QBO with various combinations of drag from the two types of waves, but there are some constraints on the wave input spectra and amplitudes. For example, if the phase speeds of the gravity waves in the input spectrum are large relative to those of the equatorial planetary waves, critical level absorption of the equatorial planetary waves may occur. The resulting mean-wind oscillation, in that case, is driven almost exclusively by the gravity wave drag, with only a small contribution from the planetary waves at low levels. With an appropriate choice of wave input parameters, it is possible to obtain a QBO with a realistic period and to which both types of waves contribute. This is the regime in which the terrestrial QBO appears to reside. There may also be constraints on the initial strength of the wind shear, and these are similar to the constraints that apply when gravity wave drag is used without any planetary wave drag. In recent years, it has been observed that, in order to simulate the QBO accurately, general circulation models require parameterized gravity wave drag, in addition to the drag from resolved planetary-scale waves, and that even if the planetary wave amplitudes are incorrect, the gravity wave drag can be adjusted to compensate. This study provides a basis for knowing that such a compensation is possible.

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