Simulation of the quasi-biennial oscillations of the zonal wind in the equatorial stratosphere: Part II. Atmospheric general circulation models

Kulyamin, D. V.; Volodin, E. M.; Dymnikov, V. P.

doi:10.1134/s0001433809010046

Cited by 17 publications

(16 citation statements)

References 11 publications

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“…2). In the fifth, we attempt to mimic the internally generated QBO in some recent climate models (e.g., Giorgetta et al 2006;Anstey et al 2010;Kulyamin et al 2009;Kawatani et al 2010;Osprey et al 2010;Hurwitz et al 2011). In many of these models the QBO winds are too weak or do not extend strongly enough below 50 hPa.…”

Section: B Methodologymentioning

confidence: 98%

The Influence of the Quasi-Biennial Oscillation on the Troposphere in Winter in a Hierarchy of Models. Part II: Perpetual Winter WACCM Runs

Garfinkel

Hartmann

2011

Journal of the Atmospheric Sciences

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Experiments with the Whole Atmosphere Community Climate Model (WACCM) are used to understand the influence of the stratospheric tropical quasi-biennial oscillation (QBO) in the troposphere. The zonally symmetric circulation in thermal wind balance with the QBO affects high-frequency eddies throughout the extratropical troposphere. The influence of the QBO is strongest and most robust in the North Pacific near the jet exit region, in agreement with observations. Variability of the stratospheric polar vortex does not appear to explain the effect of the QBO in the troposphere in the model, although it does contribute to the response in the North Atlantic. Anomalies in tropical deep convection associated with the QBO appear to damp, rather than drive, the effect of the QBO in the extratropical troposphere. Rather, the crucial mechanism whereby the QBO modulates the extratropical troposphere appears to be the interaction of tropospheric transient waves with the axisymmetric circulation in thermal wind balance with the QBO. The response to QBO winds of realistic amplitude is stronger for perpetual February radiative conditions and sea surface temperatures than perpetual January conditions, consistent with the observed response in reanalysis data, in a coupled seasonal WACCM integration, and in dry model experiments described in Part I.

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Section: B Methodologymentioning

confidence: 98%

The Influence of the Quasi-Biennial Oscillation on the Troposphere in Winter in a Hierarchy of Models. Part II: Perpetual Winter WACCM Runs

Garfinkel

Hartmann

2011

Journal of the Atmospheric Sciences

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“…However, a few GCMs have had some success in simulating stratospheric mean flow oscillations that are similar in many respects to the observed QBO. A number of models have accomplished this only by incorporation of a parameterization of momentum transport by nonstationary gravity waves (e.g., Scaife et al 2000;Giorgetta et al 2002Giorgetta et al , 2006Shibata and Deushi 2005;Kulyamin et al 2009). Only a few models have produced QBO-like oscillations with only explicitly resolved waves (Takahashi 1996(Takahashi , 1999Hamilton et al 1999Hamilton et al , 2001Watanabe and Takahashi 2005;Kawatani et al 2005Kawatani et al , 2009Kawatani et al , 2010a.…”

Section: Introductionmentioning

confidence: 99%

The Quasi-Biennial Oscillation in a Double CO2 Climate

Kawatani

Hamilton

Watanabe

2011

Journal of the Atmospheric Sciences

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The effects of anticipated twenty-first-century global climate change on the stratospheric quasi-biennial oscillation (QBO) have been studied using a high-resolution version of the Model for Interdisciplinary Research on Climate (MIROC) atmospheric GCM. This version of the model is notable for being able to simulate a fairly realistic QBO for present-day conditions including only explicitly resolved nonstationary waves. A long control integration of the model was run with observed climatological sea surface temperatures (SSTs) appropriate for the late twentieth century, followed by another integration with increased atmospheric CO 2 concentration and SSTs incremented by the projected twenty-first-century warming in a multimodel ensemble of coupled ocean-atmosphere runs that were forced by the Special Report on Emissions Scenarios (SRES) A1B scenario of future atmospheric composition. In the experiment for late twenty-first-century conditions the QBO period becomes longer and QBO amplitude weaker than in the late twentieth-century simulation. The downward penetration of the QBO into the lowermost stratosphere is also curtailed in the late twenty-first-century run. These changes are driven by a significant (30%-40%) increase of the mean upwelling in the equatorial stratosphere, and the effect of this enhanced mean circulation overwhelms counteracting influences from strengthened wave fluxes in the warmer climate. The momentum fluxes associated with waves propagating upward into the equatorial stratosphere do strengthen overall by ;(10%-15%) in the warm simulation, but the increases are almost entirely in zonal phase speed ranges that have little effect on the stratospheric QBO but that would be expected to have important influences in the mesosphere and lower thermosphere.

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“…It reproduces QBOs with characteristics close to those observed [24]. Problems of QBO struc tural stability and synchronization with various peri odical processes (the Sun's annual cycle, the equato rial wind's semi annual oscillations, etc.)…”

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confidence: 53%