scholarly journals How can we improve the driving of the Quasi-Biennial Oscillation in climate models?

2020 ◽  
Author(s):  
Albert Hertzog
Keyword(s):  
Climate Models ◽  
Quasi Biennial Oscillation ◽  
Biennial Oscillation

scholarly journals Development of a climate record of tropospheric and stratospheric ozone from satellite remote sensing: evidence of an early recovery of global stratospheric ozone

2012 ◽  
Vol 12 (1) ◽  
pp. 3169-3211
Author(s):  
J. R. Ziemke ◽  
S. Chandra
Keyword(s):  
Climate Models ◽  
Stratospheric Ozone ◽  
Steady Increase ◽  
Ozone Monitoring Instrument ◽  
Early Recovery ◽  
Quasi Biennial Oscillation ◽  
Time Record ◽  
The Tropics ◽  
Biennial Oscillation

Abstract. Ozone data beginning October 2004 from the Aura Ozone Monitoring Instrument (OMI) and Aura Microwave Limb Sounder (MLS) are used to evaluate the accuracy of the Cloud Slicing technique in effort to develop long data records of tropospheric and stratospheric ozone and for studying their long-term changes. Using this technique, we have produced a 32-yr (1979–2010) long record of tropospheric and stratospheric ozone from the combined Total Ozone Mapping Spectrometer (TOMS) and OMI. The analyses of these time series suggest that the quasi-biennial oscillation (QBO) is the dominant source of inter-annual variability of stratospheric ozone and is clearest in the Southern Hemisphere during the Aura time record with related inter-annual changes of 30–40 Dobson Units. Tropospheric ozone also indicates a QBO signal in the tropics with peak-to-peak changes varying from 2 to 7 DU. The stratospheric ozone record indicates a steady increase since the mid-1990's with current ozone levels comparable to the mid-1980's. This is earlier than predicted by many of the current climate models which suggest recovery to the mid-1980's levels by year 2020 or later.

Development of the Extratropical Response to the Stratospheric Quasi-Biennial Oscillation

2021 ◽  
pp. 1-44
Author(s):  
Jian Rao ◽  
Chaim I. Garfinkel ◽  
Ian P. White
Keyword(s):  
Climate Models ◽  
Meridional Circulation ◽  
Polar Vortex ◽  
Late Winter ◽  
Flux Divergence ◽  
Quasi Biennial Oscillation ◽  
Atlantic Sector ◽  
Near Surface ◽  
Surface Response ◽  
Biennial Oscillation

AbstractUsing the Model of an Idealized Moist Atmosphere (MiMA) capable of spontaneously generating a Quasi-Biennial Oscillation (QBO), the gradual establishment of the extratropical response to the QBO is explored. The period and magnitude of the QBO and the magnitude of the polar Holton-Tan (HT) relationship is simulated in a free-running configuration of MiMA, comparable to that in state-of-the-art climate models. In order to isolate mechanisms whereby the QBO influences variability outside of the tropical atmosphere, a series of branch experiments are performed with nudged QBO winds. When easterly QBO winds maximized around 30 hPa are relaxed, an Eliassen-Palm (E-P) flux divergence dipole quickly forms in the extratropical middle stratosphere as a direct response to the tropical meridional circulation, in contrast to the HT mechanism which is associated with wave propagation near the zero wind line. This meridional circulation response to the relaxed QBO winds develops within the first 10 days in seasonally-varying and fixed-seasonal experiments. No detectable changes in upward propagation of waves in the midlatitude lowermost stratosphere are evident for at least 20 days after branching, with the first changes only evident after 20 days in perpetual midwinter and season-varying runs, but after 40 days in perpetual November runs. The polar vortex begins to respond around the 20th day, and subsequently a near-surface response in the Atlantic sector forms in mid-to-late winter runs. These results suggest that the maximum near-surface response observed in mid-to-late winter is not simply due to a random seasonal synchronization of the QBO phase, but also due to the long (short) lag of the surface response to a QBO relaxation in early (mid-to-late) winter.

scholarly journals Climatology and Forcing of the Quasi-Biennial Oscillation in the MAECHAM5 Model

2006 ◽  
Vol 19 (16) ◽  
pp. 3882-3901 ◽  
Author(s):  
M. A. Giorgetta ◽  
E. Manzini ◽  
E. Roeckner ◽  
M. Esch ◽  
L. Bengtsson
Keyword(s):  
Gravity Wave ◽  
Zonal Wind ◽  
General Circulation ◽  
Large Scale ◽  
Climate Models ◽  
Middle Atmosphere ◽  
General Circulation Models ◽  
Wave Drag ◽  
Quasi Biennial Oscillation ◽  
Biennial Oscillation

Abstract The quasi-biennial oscillation (QBO) in the equatorial zonal wind is an outstanding phenomenon of the atmosphere. The QBO is driven by a broad spectrum of waves excited in the tropical troposphere and modulates transport and mixing of chemical compounds in the whole middle atmosphere. Therefore, the simulation of the QBO in general circulation models and chemistry climate models is an important issue. Here, aspects of the climatology and forcing of a spontaneously occurring QBO in a middle-atmosphere model are evaluated, and its influence on the climate and variability of the tropical middle atmosphere is investigated. Westerly and easterly phases are considered separately, and 40-yr ECMWF Re-Analysis (ERA-40) data are used as a reference where appropriate. It is found that the simulated QBO is realistic in many details. Resolved large-scale waves are particularly important for the westerly phase, while parameterized gravity wave drag is more important for the easterly phase. Advective zonal wind tendencies are important for asymmetries between westerly and easterly phases, as found for the suppression of the easterly phase downward propagation. The simulation of the QBO improves the tropical upwelling and the atmospheric tape recorder compared to a model without a QBO. The semiannual oscillation is simulated realistically only if the QBO is represented. In sensitivity tests, it is found that the simulated QBO is strongly sensitive to changes in the gravity wave sources. The sensitivity to the tested range of horizontal resolutions is small. The stratospheric vertical resolution must be better than 1 km to simulate a realistic QBO.

scholarly journals Response of the quasi-biennial oscillation to a warming climate in global climate models

2020 ◽  
Author(s):  
Jadwiga Richter ◽  
Francois Lott ◽  
Keyword(s):  
Gravity Wave ◽  
General Circulation ◽  
Climate Models ◽  
Global Climate ◽  
General Circulation Models ◽  
Global Climate Models ◽  
Residual Velocity ◽  
Quasi Biennial Oscillation ◽  
Biennial Oscillation ◽  
Wave Momentum

<p>We compare the response of the quasi-biennial oscillation (QBO) to a warming climate in eleven atmosphere general circulation models that performed time-slice simulations for present-day, doubled,  and  quadrupled CO<sub>2</sub> climates.  No consistency was found among the models for the QBO period response, with the period decreasing by eight months in some models and lengthening by up to thirteen months in others in the doubled CO<sub>2</sub>  simulations.  In the quadruped CO<sub>2</sub> simulations  a reduction in QBO period of 14 months was found in some models, whereas in several others the tropical oscillation no longer resembled the present day QBO, although could still be identified in the deseasonalized zonal mean zonal wind timeseries.  In contrast, all the models projected a decrease in the  QBO amplitude in a warmer climate with the largest relative decrease  near 60 hPa. In simulations with doubled and quadrupled CO<sub>2</sub> the multi-model mean QBO amplitudes decreased by 36\% and 51\%, respectively. Across the  models the differences in the QBO period response were most strongly related to how the gravity wave momentum flux entering the stratosphere and tropical vertical residual velocity responded to the increases in CO<sub>2</sub> amounts. Likewise it was found that the robust decrease in QBO amplitudes was correlated across the models to changes in vertical residual velocity, parameterized gravity wave momentum fluxes, and to some degree the resolved upward wave flux.  We argue that uncertainty in the representation of the parameterized gravity waves is the most likely cause of the spread among the eleven models in the QBO's response to climate change.</p>

scholarly journals Snow–(N)AO Teleconnection and Its Modulation by the Quasi-Biennial Oscillation

2017 ◽  
Vol 30 (24) ◽  
pp. 10211-10235 ◽  
Author(s):  
Y. Peings ◽  
H. Douville ◽  
J. Colin ◽  
D. Saint Martin ◽  
Gudrun Magnusdottir
Keyword(s):  
General Circulation ◽  
Climate Models ◽  
Polar Vortex ◽  
General Circulation Models ◽  
Destructive Interference ◽  
Atmospheric Response ◽  
Quasi Biennial Oscillation ◽  
Atmospheric General Circulation Models ◽  
Biennial Oscillation

This study explores the wintertime extratropical atmospheric response to Siberian snow anomalies in fall, using observations and two distinct atmospheric general circulation models. The role of the quasi-biennial oscillation (QBO) in modulating this response is discussed by differentiating easterly and westerly QBO years. The remote influence of Siberian snow anomalies is found to be weak in the models, especially in the stratosphere where the “Holton–Tan” effect of the QBO dominates the simulated snow influence on the polar vortex. At the surface, discrepancies between composite analyses from observations and model results question the causal relationship between snow and the atmospheric circulation, suggesting that the atmosphere might have driven snow anomalies rather than the other way around. When both forcings are combined, the simulations suggest destructive interference between the response to positive snow anomalies and easterly QBO (and vice versa), at odds with the hypothesis that the snow–North Atlantic Oscillation/Arctic Oscillation [(N)AO] teleconnection in recent decades has been promoted by the QBO. Although model limitations in capturing the relationship exist, altogether these results suggest that the snow–(N)AO teleconnection may be a stochastic artifact rather than a genuine atmospheric response to snow-cover variability. This study adds to a growing body of evidence suggesting that climate models do not capture a robust and stationary snow–(N)AO relationship. It also highlights the need for extending observations and/or improving models to progress on this matter.

scholarly journals Has Stratospheric HCl in the Northern Hemisphere Been Increasing Since 2005?

2020 ◽  
Vol 8 ◽  
Author(s):  
Yuanyuan Han ◽  
Fei Xie ◽  
Jiankai Zhang
Keyword(s):  
Northern Hemisphere ◽  
Climate Models ◽  
Linear Trend ◽  
Polar Vortex ◽  
Joint Effect ◽  
Residual Circulation ◽  
Quasi Biennial Oscillation ◽  
Middle Latitudes ◽  
The North ◽  
Biennial Oscillation

Stratospheric hydrogen chloride (HCl) is the main stratospheric reservoir of chlorine, deriving from the decomposition of chlorine-containing source gases. Its trend has been used as a metric of ozone depletion or recovery. Using the latest satellite observations, it is found that the significant increase of Northern Hemisphere stratospheric HCl during 2010–2011 can mislead the trend of HCl in recent decades. In agreement with previous studies, HCl increased from 2005 to 2011; however, when the large increase of stratospheric HCl during 2010–2011 is removed, the increasing linear trend from 2005 to 2011 becomes weak and insignificant. In addition, the linear trend of Northern Hemisphere stratospheric HCl from 2005 to 2016 is also weak and insignificant. The significant increase of HCl during 2010–2011 is attributed to a strong northern polar vortex and a weakened residual circulation, which slowed down the transport of HCl between the low-mid latitudes and the high latitudes, leading to an accumulation of HCl in the middle latitudes of the stratosphere. In addition, a weakened residual circulation leads to enhance conversion of chlorine-containing source gases of different lifetimes to HCl, thus increasing the levels of HCl. Simulations by both chemistry transport and chemistry-climate models support the result. It is further found that the joint effect of a La Niña event, the west phase of the quasi-biennial oscillation and positive anomalies of sea surface temperature in the North Pacific is responsible for the strong northern polar vortex and a weakened residual circulation.

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