The Quasi-biennial Oscillation and annual variations in tropical ozone from SHADOZ and HALOE

Abstract. We examine the tropical ozone mixing ratio perturbation fields generated from a monthly ozone climatology using 1998 to 2006 ozonesonde data from the Southern Hemisphere Additional Ozonesondes (SHADOZ) network and the 13-year satellite record from 1993 to 2005 obtained from the Halogen Occultation Experiment (HALOE). The long time series and high vertical resolution of the ozone and temperature profiles from the SHADOZ sondes coupled with good tropical coverage north and south of the equator gives a detailed picture of the ozone structure in the lowermost stratosphere down through the tropopause where the picture obtained from HALOE measurements is blurred by coarse vertical resolution. Ozone perturbations respond to annual variations in the Brewer-Dobson Circulation (BDC) in the region just above the cold-point tropopause to around 20 km. Annual cycles in ozone and temperature are well correlated. Above 20 km, ozone and temperature perturbations are dominated by the Quasi-biennial Oscillation (QBO). Both satellite and sonde records show good agreement between positive and negative ozone mixing ratio anomalies and alternating QBO westerly and easterly wind shears from the Singapore rawinsondes with a mean periodicity of 26 months for SHADOZ and 25 months for HALOE. There is a temporal offset of one to three months with the QBO wind shear ahead of the ozone anomaly field. The meridional length scales for the annual cycle and the QBO, obtained using the temperature anomalies and wind shears in the thermal wind equation, compare well with theoretical calculations.

Download Full-text

The Quasi-biennial Oscillation and annual variations in tropical ozone from SHADOZ and HALOE

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-8-6355-2008 ◽

2008 ◽

Vol 8 (2) ◽

pp. 6355-6378 ◽

Cited By ~ 3

Author(s):

J. C. Witte ◽

M. R. Schoeberl ◽

A. R. Douglass ◽

A. M. Thompson

Keyword(s):

Theoretical Calculations ◽

Vertical Resolution ◽

Mixing Ratio ◽

Quasi Biennial Oscillation ◽

Temperature Anomalies ◽

Annual Variations ◽

Horizontal Length ◽

Wind Shears ◽

Cold Point ◽

Biennial Oscillation

Abstract. We examine the tropical ozone mixing ratio perturbation fields generated from a monthly ozone climatology using 1998 to 2006 ozonesonde data from the Southern Hemisphere Additional Ozonesondes (SHADOZ) network and the 13 year satellite record from 1993 to 2005 obtained from the Halogen Occultation Experiment (HALOE). The lengthy time series and high vertical resolution of the ozone and temperature profiles from the SHADOZ sondes coupled with good tropical coverage north and south of the equator gives a detailed picture of the ozone structure in the lowermost stratosphere down through the tropopause where the picture obtained from HALOE measurements is blurred by coarse vertical resolution. Ozone perturbations respond to annual variations in the Brewer-Dobson Circulation (BDC) in the region just above the cold-point tropopause to around 20 km. Strong annual signals of alternating positive and negative ozone anomalies are observed and correlate well with temperature anomalies. Above 20 km, ozone and temperature perturbations are dominated by the Quasi-biennial Oscillation (QBO). Both satellite and sonde records show good agreement between positive and negative ozone mixing ratio anomalies and alternating QBO easterly and westerly wind shears from the Singapore rawinsondes with a mean periodicity of 26 months for SHADOZ and 25 months for HALOE. There is a temporal offset of one to three months with the ozone QBO preceding the wind shear. Horizontal length scales for the annual cycle and the QBO, obtained using the temperature anomalies and wind shears in the thermal wind equation, compare well with theoretical calculations.

Download Full-text

The Influence of the Quasi-Biennial Oscillation on the Troposphere in Winter in a Hierarchy of Models. Part I: Simplified Dry GCMs

Journal of the Atmospheric Sciences ◽

10.1175/2011jas3665.1 ◽

2011 ◽

Vol 68 (6) ◽

pp. 1273-1289 ◽

Cited By ~ 50

Author(s):

Chaim I. Garfinkel ◽

Dennis L. Hartmann

Keyword(s):

Zonal Wind ◽

Climate Model ◽

Polar Vortex ◽

Equation Model ◽

Quasi Biennial Oscillation ◽

Stratospheric Polar Vortex ◽

The North ◽

Subtropical Jet ◽

Long Time ◽

Biennial Oscillation

Abstract A dry primitive equation model is used to explain how the quasi-biennial oscillation (QBO) of the tropical stratosphere can influence the troposphere, even in the absence of tropical convection anomalies and a variable stratospheric polar vortex. QBO momentum anomalies induce a meridional circulation to maintain thermal wind balance. This circulation includes zonal wind anomalies that extend from the equatorial stratosphere into the subtropical troposphere. In the presence of extratropical eddies, the zonal wind anomalies are intensified and extend downward to the surface. The tropospheric response differs qualitatively between integrations in which the subtropical jet is strong and integrations in which the subtropical jet is weak. While fluctuation–dissipation theory provides a guide to predicting the response in some cases, significant nonlinearity in others, particularly those designed to model the midwinter subtropical jet of the North Pacific, prevents its universal application. When the extratropical circulation is made zonally asymmetric, the response to the QBO is greatest in the exit region of the subtropical jet. The dry model is able to simulate much of the Northern Hemisphere wintertime tropospheric response to the QBO observed in reanalysis datasets and in long time integrations of the Whole Atmosphere Community Climate Model (WACCM).

Download Full-text

Quasi-biennial oscillation of the tropical stratospheric aerosol layer

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-5557-2015 ◽

2015 ◽

Vol 15 (10) ◽

pp. 5557-5584 ◽

Cited By ~ 14

Author(s):

R. Hommel ◽

C. Timmreck ◽

M. A. Giorgetta ◽

H. F. Graf

Keyword(s):

Seasonal Variations ◽

Stratospheric Aerosol ◽

Static Balance ◽

Aerosol Layer ◽

Mixing Ratio ◽

Quasi Biennial Oscillation ◽

Mixing Ratios ◽

Vertical Extent ◽

Biennial Oscillation ◽

Stratospheric Aerosols

Abstract. This study describes how aerosol in an aerosol-coupled climate model of the middle atmosphere is influenced by the quasi-biennial oscillation (QBO) during times when the stratosphere is largely unperturbed by volcanic material. In accordance with satellite observations, the vertical extent of the stratospheric aerosol layer in the tropics is modulated by the QBO by up to 6 km, or ~ 35% of its mean vertical extent between 100–7 hPa (about 16–33 km). Its largest vertical extent lags behind the occurrence of strongest QBO westerlies. The largest reduction lags behind maximum QBO easterlies. Strongest QBO signals in the aerosol surface area (30 %) and number densities (up to 100% e.g. in the Aitken mode) are found in regions where aerosol evaporates, that is above the 10 hPa pressure level (~ 31 km). Positive modulations are found in the QBO easterly shear, negative modulations in the westerly shear. Below 10 hPa, in regions where the aerosol mixing ratio is largest (50–20 hPa, or ~ 20–26 km), in most of the analysed parameters only moderate statistically significant QBO signatures (< 10%) have been found. QBO signatures in the model prognostic aerosol mixing ratio are significant at the 95% confidence level throughout the tropical stratosphere where modelled mixing ratios exceed 0.1 ppbm. In some regions of the tropical lower stratosphere the QBO signatures in other analysed parameters are partly not statistically significant. Peak-to-peak amplitudes of the QBO signature in the prognostic mixing ratios are up to twice as large as seasonal variations in the region where aerosols evaporate and between 70–30 hPa. Between the tropical tropopause and 70 hPa the QBO signature is relatively weak and seasonal variations dominate the variability of the simulated Junge layer. QBO effects on the upper lid of the tropical aerosol layer turn the quasi-static balance between processes maintaining the layer's vertical extent into a cyclic balance when considering this dominant mode of atmospheric variability. Global aerosol-interactive models without a QBO are only able to simulate the quasi-static balance state. To assess the global impact of stratospheric aerosols on climate processes, those partly nonlinear relationships between the QBO and stratospheric aerosols have to be taken into account.

Download Full-text

Characteristics of quasi-biennial oscillation over Kenya and their predictability potential for the seasonal rainfall

MAUSAM ◽

10.54302/mausam.v45i1.1878 ◽

2022 ◽

Vol 45 (1) ◽

pp. 57-62

Author(s):

L.J . OGALLO ◽

R. E. OKOOLA ◽

D. N. WANJOHI

Keyword(s):

Seasonal Rainfall ◽

Quasi Biennial Oscillation ◽

Easterly Wind ◽

S Period ◽

Biennial Oscillation

investigated using monthly zo.ta l wind com ponents from Nairob i (Kenya ) within the period1966-1987. RelatiHn.;;hips between the stra tospher ic eas terl y and westerly wino phases and t he seasona l ra infallanomalics were also iO\t,"..')t igatN.Res ults Irom spec tra l a nalysis indicated tho d ominance (If a 28 mon th s' period in the IllOal w ind comnoncn.The \'Crtical ra te of propagar ioa of both westerly and easterly wind phases was about - · 1.2 kmmonth.Results from statist ical analysis indicated signitica nr (at 5 '~~ level) association between rainfall anomalyclass (above normal. normal. a mi below normal) and east erly and westerl y wind phas...es.

Download Full-text

Stratospheric and mesospheric temperature variations for the quasi-biennial and semiannual (QBO and SAO) oscillations based on measurements from SABER (TIMED) and MLS (UARS)

Annales Geophysicae ◽

10.5194/angeo-24-2131-2006 ◽

2006 ◽

Vol 24 (8) ◽

pp. 2131-2149 ◽

Cited By ~ 56

Author(s):

F. T. Huang ◽

H. G. Mayr ◽

C. A. Reber ◽

J. M. Russell ◽

J. G. Mengel ◽

...

Keyword(s):

Local Maximum ◽

Altitude Range ◽

Quasi Biennial Oscillation ◽

Temperature Variations ◽

Annual Variations ◽

Mesospheric Temperature ◽

Phase Variations ◽

Phase Progression ◽

Biennial Oscillation ◽

Rare Opportunity

Abstract. We present the zonal mean temperature variations for the quasi-biennial oscillation (QBO) and the semiannual oscillation (SAO) based on data from SABER on the TIMED spacecraft (years 2002 to 2004) and from MLS on the UARS mission (1992 to 1994). The SABER measurements provide the rare opportunity to analyze data from one instrument over a wide altitude range (15 to 95 km), while MLS data were taken in the 16 to 55 km altitude range a decade earlier. The results are presented for latitudes from 48° S to 48° N. New results are obtained for the QBO, especially in the upper stratosphere and mesosphere, and at mid-latitudes. At Equatorial latitudes, the QBO amplitudes show local peaks, albeit small, that occur at different altitudes. From about 20 to 40 km, and within about 15° of the Equator, the amplitudes can approach 3.5° K for the stratospheric QBO (SQBO). For the mesospheric QBO (MQBO), we find peaks near 70 km, with temperature amplitudes reaching 3.5° K, and near 85 km, the amplitudes approach 2.5° K. Morphologically, the amplitude and phase variations derived from the SABER and MLS measurements are in qualitative agreement. As a function of latitude, the QBO amplitudes tend to peak at the Equator but then increase again pole-ward of about 15° to 20°. The phase progression with altitude varies more gradually at the Equator than at mid-latitudes. Many of the SAO results presented are also new, in part because measurements were not previously available or were more limited in nature. At lower altitudes near 45 km, within about 15° of the Equator, the temperature amplitudes for the stratospheric SAO (SSAO) reveal a local maximum of about 5° K. At higher altitudes close to the Equator, our results show separate peaks of about 7° K near 75 and 90 km for the mesospheric SAO (MSAO). In the SAO results, significant inter-annual differences are evident, with the amplitudes being largest in 2002 relative to 2003 and 2004. As in the case for the QBO, the SAO temperature amplitudes go through minima away from the Equator, and then increase towards mid latitudes, especially at altitudes above 55 km. We compare our findings with previously published empirical results, and with corresponding results from the numerical spectral model (NSM). Although not a focus of this study, we also show results for the inter-annual variations (which appear to be generated at least in part by the QBO) of the migrating diurnal tide. In the upper mesosphere, their amplitudes can approach 20° K, and they are derived jointly with the zonal-mean components.

Download Full-text

Effects of the Quasi-Biennial Oscillation and Stratospheric Semiannual Oscillation on Tracer Transport in the Upper Stratosphere

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-12-053.1 ◽

2013 ◽

Vol 70 (5) ◽

pp. 1370-1389 ◽

Cited By ~ 10

Author(s):

Jianchuan Shu ◽

Wenshou Tian ◽

Dingzhu Hu ◽

Jiankai Zhang ◽

Lin Shang ◽

...

Keyword(s):

Gravity Wave ◽

Climate Model ◽

Mixing Ratio ◽

Tracer Transport ◽

Double Peak ◽

Quasi Biennial Oscillation ◽

Wave Source ◽

Northern Hemispheric ◽

Biennial Oscillation ◽

Semiannual Oscillation

Abstract Using satellite observations together with a chemistry–climate model (CCM), the effect of the stratospheric semiannual oscillation (SAO) and quasi-biennial oscillation (QBO) on the equatorial double peak in observed CH4 and NO2 is reexamined. It is concluded that the lower-equatorial Halogen Occultation Experiment (HALOE) CH4 mixing ratio of the April double peak in 1993 and 1995 was associated with the prominent first cycle of the SAO westerlies, which causes local vertical downwelling in the upper equatorial stratosphere. The observational evidences imply that the strong westerlies of the first cycle of the stratospheric SAO in 1993 and 1995 were driven by enhanced lower-stratospheric gravity wave activity in the early parts of those years. The CCM simulations further verify that the gravity wave source strength has a large impact on the development and strength of the SAO westerlies. This result suggests that the equatorial long-lived tracer mixing ratio near the stratopause (which is associated with the strength of the SAO westerlies) was not only modulated by the QBO phase, but was also significantly influenced by interannual variation in the gravity waves. It is also found that the deeper equatorial trough of the double peak is unlikely to be always accompanied by the more prominent Northern Hemispheric lobe, and the Northern Hemispheric lobe of the double peak can be mainly attributed to subtropical upwelling. The altitude of greatest chemical destruction anomalies associated with the SAO and QBO is below the trough of the double peak, implying that the effect of the chemical process on the double peak is insignificant.

Download Full-text

Does the coupling of the semiannual oscillation with the quasi-biennial oscillation provide predictability of Antarctic sudden stratospheric warmings?

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-12835-2021 ◽

2021 ◽

Vol 21 (17) ◽

pp. 12835-12853

Author(s):

Viktoria J. Nordström ◽

Annika Seppälä

Keyword(s):

Polar Vortex ◽

Reanalysis Data ◽

Early Winter ◽

Flux Divergence ◽

Quasi Biennial Oscillation ◽

Easterly Wind ◽

Wave Forcing ◽

A Minor ◽

Biennial Oscillation ◽

Semiannual Oscillation

Abstract. During September 2019 a minor sudden stratospheric warming took place over the Southern Hemisphere (SH), bringing disruption to the usually stable winter vortex. The mesospheric winds reversed and temperatures in the stratosphere rose by over 50 K. Whilst sudden stratospheric warmings (SSWs) in the SH are rare, with the only major SSW having occurred in 2002, the Northern Hemisphere experiences about six per decade. Amplification of atmospheric waves during winter is thought to be one of the possible triggers for SSWs, although other mechanisms are also possible. Our understanding, however, remains incomplete, especially with regards to SSW occurrence in the SH. Here, we investigate the effect of two equatorial atmospheric modes, the quasi-biennial oscillation (QBO) at 10 hPa and the semiannual oscillation (SAO) at 1 hPa during the SH winters of 2019 and 2002. Using MERRA-2 reanalysis data we find that the easterly wind patterns resembling the two modes merge at low latitudes in the early winter, forming a zero-wind line that stretches from the lower stratosphere into the mesosphere. This influences the meridional wave guide, resulting in easterly momentum being deposited in the polar atmosphere throughout the polar winter, decelerating the westerly winds in the equatorward side of the polar vortex. As the winter progresses, the momentum deposition and wind anomalies descend further down into the stratosphere. We find similar behaviour in other years with early onset SH vortex weakening events. The magnitude of the SAO and the timing of the upper stratospheric (10 hPa) easterly QBO signal was found to be unique in these years when compared to the years with a similar QBO phase. We were able to identify the SSW and weak vortex years from the early winter location of the zero-wind line at 1 hPa together with Eliassen–Palm flux divergence in the upper stratosphere at 40–50∘ S. We propose that this early winter behaviour resulting in deceleration of the polar winds may precondition the southern atmosphere for a later enhanced wave forcing from the troposphere, resulting in an SSW or vortex weakening event. Thus, the early winter equatorial upper stratosphere–mesosphere, together with the polar upper atmosphere, may provide early clues to an imminent SH SSW.

Download Full-text