Relation between Quasi-Decadal and Quasi-Biennial Oscillations of Solar Activity and the Equatorial Stratospheric Wind (original) (raw)
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Possible ozone influence on the quasi-biennial oscillation in the equatorial stratosphere
Doklady Earth Sciences, 2010
Cross spectral analysis between the time series of zonal wind velocity in the equatorial stratosphere and the flux of solar UV radiation revealed high coherence between the variations of these two parameters on a quasi biennial scale (24-30 months) in the atmo spheric layer 500-1 hPa (~6-48.5 km). A lag of the quasi biennial variations in wind velocity behind the quasi biennial variations in the solar radiation flux, the maximum (~ 24 months) of which is located at a level of 100 hPa (16.5 km), decreases with height, and in the stratopause region (~1 hPa), the wind velocity variations are approximately in phase with the varia tions in the solar radiation flux. This points at the pos sibility of the influence of quasi biennial variations in the short wave solar radiation on the quasi biennial oscillation of the zonal wind in the neighborhood of the equatorial stratopause. It has been shown that the meridional gradient and the curvature degree of the meridional profile of ozone concentration in this layer undergo quasi biennial variations such that could be a cause of synchronization between the quasi biennial variations in the wind velocity and thermal variations according to the solar wind equation.
Longitudinal Variations of the Stratospheric Quasi-biennial Oscillation
Journal of the Atmospheric Sciences, 2004
The longitudinal dependence of interannual variations of tropical stratospheric wind is examined in a detailed general circulation model simulation and in the limited observations available. A version of the SKYHI model is run with an imposed zonally symmetric zonal momentum source that forces the zonal-mean zonal wind evolution in the tropical stratosphere to be close to an estimate of the observed zonal wind based on radiosonde observations at Singapore during the period 1978-99. This amounts to a kind of simple assimilation model in which only the zonal-mean wind field in the tropical stratosphere is assimilated, and other quantities are allowed to vary freely. A total of five experiments were run, one covering the full 1978-99 period and four for 1989-99.
A conceptual model relating the quasi-biennial oscillation and the tropospheric biennial oscillation
International Journal of Climatology, 2003
A survey of the zonal wind throughout the troposphere and the lower stratosphere near the equator is made for the 41 year period of 1958-98. A similar survey of the 500 hPa geopotential height, sea-surface temperature (SST) and tropopause height is also made, except that the survey period for the tropopause height is shorter than 41 years due to unavailability of data.
The Open Atmospheric Science Journal, 2010
The Quasi Biennial Oscillation, the downward propagating easterly and westerly wind regimes in the equatorial stratosphere, has been investigated according to robust statistics that utilizes the amplitude/vector probable error ratio to provide the confidence level of the investigated harmonic. The amplitude-to-noise ratio is found to be the highest in correspondence of the 28-month harmonic for each examined height; the relative amplitude and phase values are found, respectively, to decrease and increase with the height and to take about a year to descend from 15 to 70 hPa with a progressive lag of about 1 month/km. At the top of the stratosphere, easterlies dominate, while at the bottom, westerlies are more likely to be found.
The signal of the 11-year solar cycle in the global stratosphere
J Atmos Sol Terr Phys, 1999
The search for a signal of the 11-year sunspot cycle in the heights and temperatures of the lower stratosphere was previously successfully conducted for the northern hemisphere with a data set from the Freie Universität Berlin, covering four solar cycles. This work has been extended to the whole globe by means of the NCEP/NCAR reanalyses for the period 1968-1996. The re-analyses show that the signal exists in the southern hemisphere too, and that it is of nearly the same size and shape as on the northern hemisphere. The NCEP/NCAR reanalyses yield higher correlations with the solar cycle than do the Berlin analyses for the same period, because the interannual variability is lower in the NCEP/NCAR data. The correlations between the solar cycle and the zonally averaged temperatures at the standard levels between 200 and 10 hPa are largest between the tropopause and the 25 km level, that is, in the ozone layer. This may be partly a direct effect in this layer, because of more absorber (ozone) and more ultraviolet radiation from the sun in the peaks of the 11-year solar cycle. However, it is more likely to be mainly an indirect dynamical consequence of UV absorption by ozone in the middle and upper stratosphere. The largest temperature correlations move with the sun from one summer hemisphere to the other, and the largest height correlations move poleward from winter to summer.
The global signal of the 11-year solar cycle in the stratosphere: observations and models
Journal of Atmospheric and Solar-terrestrial Physics, 2002
Earlier studies used the data from four solar cycles, to examine the global structure of the signal of the 11-year sunspot cycle (SSC) in the stratosphere and troposphere, using correlations between the solar cycle and heights and temperatures at different pressure levels. Here, this work is expanded in Part I to show the differences of geopotential heights and temperatures between maxima and minima of the SSC. This study puts the earlier work on a firmer ground and gives quantitative values for comparisons with models. In Part II, two general circulation models (GCMs) with coupled stratospheric chemistry are used to simulate the impact of changes in solar output. This paper is not intended as a review of the whole topic of solar impacts, but provides some results recently obtained in observations and modelling.Comparisons between the GCM results and observations show that the differences between solar maximum and solar minimum for temperature and ozone are generally smaller than observed. In the middle and upper stratosphere, models are closer to agreeing with observations of temperature, but a significant observed temperature difference near is not reproduced in the models. Also, model predictions of the shape of the vertical profile of the ozone difference do not agree with observations and the comparisons are hindered by large statistical uncertainties in both models and observations. Nonetheless, the results are an improvement on 2-D model results in showing a larger ozone signal in the lower stratosphere.
Atmosphere-Ocean, 1984
A simple perturbation procedure is developed for incorporating the effects of mean zonal winds in atmospheric tidal calculations. This method is used to determine the variation of the solar semidiurnal surface pressure oscillation, S 2 (p), that is expected to result from the mean wind changes during the course of the quasi-biennial oscillation of the tropical stratosphere. The results are consistent with earlier observations of a quasi-biennial variation in S 2 (p). Some new observations of biennial variability in S 2 (p) at four tropical stations are also discussed. RÉSUMÉ On a développé un simple procédé de perturbation afin d'incorporer l' effet des vents moyens zonaux dans le calcul de la marée atmosphérique. Cette méthode a été utilisée pour déterminer la variation dans l'oscillation semidiurne solaire de la pression en surface S 2 (p), qui résulterait des variations dans le vent moyen au cours de l'oscillation quasi-biennale de la stratosphère tropicale. Les résultats concordent avec les observations antérieures de la variation quasi-biennale de S 2 (p). On discute aussi de nouvelles observations de quatre stations tropicales effectuées sur la variabilité de V oscillation quasi-biennale de S 2 (p)
The equatorial-stratospheric wind that shows a Quasi Biennial Oscillation (22-32 months) has been revisited using a dual statistical detail regarding the search of the dominance harmonics. Data were used from the Freie Universitat of Berlin since 1953 for different heights combining the observations of the three radiosonde stations. The dominant period of 28 months has been reaffirmed but with a discernible amplitude and a phase, respectively, inversely varying with height. Such a cycle suggests an estimate for the coming easterly equatorial wind occurrence at 15 hPa level at the end of 2009. The 28-month harmonic is found to take about a year to descend from 15 to 70 hPa with a progressive lag of about 1 month/km. At the top of the stratosphere, easterlies dominate, while at the bottom, westerlies are more likely to be found. Correlation with sunspot numbers and seasonal rainfall is discussed.