An Overview of Climatic Variability and its Causal Mechanisms

1976 ◽  
Vol 6 (4) ◽  
pp. 481-493 ◽  
Author(s):  
J. Murray Mitchell
Keyword(s):  
Climatic Change ◽  
Time Scales ◽  
Climatic Variability ◽  
Quasi Biennial Oscillation ◽  
Significant Events ◽  
The Earth ◽  
Climatic System ◽  
Biennial Oscillation ◽  
Modest Degree ◽  
Variance Spectrum

A variance spectrum of climatic variability is presented that spans all time scales of variability from about one hour (10−4 years) to the age of the Earth (4 × 109 years). An interpretive overview of the spectrum is offered in which a distinction is made between sources of variability that arise through stochastic mechanisms internal to the climatic system (atmosphere-ocean-cryosphere) and those that arise through forcing of the system from the outside. All identifiable mechanisms, both internal and external, are briefly defined and clarified as to their essential nature. It is concluded that most features of the spectrum of climatic variability can be given tentatively reasonable interpretations, whereas some features (in particular the quasi-biennial oscillation and the neoglacial cycle of the Holocene) remain fundamentally unexplained. The overall spectrum suggests the existence of a modest degree of deterministic forms of climatic change, but sufficient nonsystematic variability to place significant constraints both on the extent to which climate can be predicted, and on the extent to which significant events in the paleoclimatic record can ever manage to be assigned specific causes.

scholarly journals Transformation of the characteristics of quasi-biennial oscillation in a new version of the series of Wolf (relative sunspot) numbers

2019 ◽  
Vol 31 ◽  
pp. 21-26
Author(s):  
Igor Shibaev
Keyword(s):  
Magnetic Field ◽  
Solar Magnetic Field ◽  
Frequency Interval ◽  
Quasi Biennial Oscillation ◽  
Long Period ◽  
Amplitude Correction ◽  
The Earth ◽  
Minimum Solar Activity ◽  
Biennial Oscillation ◽  
Maximum Minimum

With the introduction from June 2015 of a new methodology for estimation of Wolf numbers W (or WSN — Wolf sunspot number), this series was corrected from January 1749 to May 2015, i.e. a new version of the series WSN was proposed. The greatest transformation affected the cycles of a statistically reliable part of the series (since, 1849), which was clearly reflected in their amplitude correction and, accordingly, in the long-period component of the series, determining the epoch of maximum/minimum solar activity. The quasi-biennial oscillations available in the solar magnetic field and in the total flux of its radiation also manifest themselves in a number of parameters of the Earth ionosphere and evaluation of their transformation degree is of high significance. This paper compares the characteristics of the frequency interval of the quasi-biennial oscillations of both versions of a series.

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

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.

scholarly journals Generation of a Quasi-Biennial Oscillation in an NWP Model Using a Stochastic Gravity Wave Drag Parameterization

2015 ◽  
Vol 143 (6) ◽  
pp. 2121-2147 ◽  
Author(s):  
John P. McCormack ◽  
Stephen D. Eckermann ◽  
Timothy F. Hogan
Keyword(s):  
Gravity Wave ◽  
Time Scales ◽  
Weather Prediction ◽  
Wave Drag ◽  
Significant Response ◽  
Quasi Biennial Oscillation ◽  
Westerly Flow ◽  
Nwp Model ◽  
Biennial Oscillation ◽  
Stochastic Gravity

Abstract Many operational numerical weather prediction (NWP) systems now extend into the stratosphere and are beginning to be used to generate forecasts beyond conventional 5–10-day periods out to seasonal time scales. Past observational and modeling studies have shown that the quasi-biennial oscillation (QBO) in equatorial stratospheric winds can play an important role in stratosphere–troposphere dynamical coupling over these longer time scales. Consequently, stratosphere-resolving NWP models used to generate seasonal forecasts should contain the necessary physics to generate and maintain the QBO. This study describes several key modifications that were necessary to produce a QBO in a high-altitude NWP model, which include an increase in model vertical resolution, implementation of a computationally efficient stochastic gravity wave drag parameterization, and reductions in the amount of horizontal and vertical diffusion in the stratosphere. Results from a 10-yr free-running model simulation with these modifications show that the westerly QBO phase produces lower temperatures and stronger westerly flow in the Northern Hemisphere (NH) winter polar stratosphere compared to the easterly QBO phase. Ensembles of 120-day simulations over the December–March period show that these modifications replace persistent easterly flow in the equatorial lower stratosphere with a more realistic transition from easterly to westerly flow. The resulting changes in planetary wave propagation produce a statistically significant response in the dynamics of the NH extratropical stratosphere consistent with the Holton–Tan relationship. The westerly shift in equatorial winds also produces a significant response in the NH extratropical troposphere, where the sea level pressure differences in winter resemble the positive phase of the northern annular mode.

scholarly journals How Does the Quasi-Biennial Oscillation Affect the Stratospheric Polar Vortex?

2013 ◽  
Vol 71 (1) ◽  
pp. 391-409 ◽  
Author(s):  
Peter A. G. Watson ◽  
Lesley J. Gray
Keyword(s):  
Time Scales ◽  
Transient Response ◽  
General Circulation ◽  
Polar Vortex ◽  
Circulation Model ◽  
Quasi Biennial Oscillation ◽  
Stratospheric Polar Vortex ◽  
Novel Approach ◽  
Dynamical Time ◽  
Biennial Oscillation

Abstract The stratospheric polar vortex is weaker in the easterly phase of the quasi-biennial oscillation (QBO-E) than in the westerly phase (QBO-W), but the mechanism behind the QBO's influence is not well understood. The composite difference of the atmospheric state between QBO-E and QBO-W is found to closely resemble the structure of the northern annular mode, the leading empirical orthogonal function of stratospheric variability, including its wave components. Studies of dynamical systems indicate that many different forcings could give rise to this response, and therefore this composite difference does not provide much information about the forcing mechanism. It is argued that the full transient response of a system to an applied forcing is likely to be much more informative about the dynamics of the forcing mechanism, especially the response on time scales shorter than the dynamical time scale, which is about a week for vortex variability. It is shown that the transient response of the vortex to forcing by the QBO in a general circulation model is consistent with the proposed mechanism of Holton and Tan, indicating that this mechanism has a role in the QBO modulation of vortex strength, in contrast to the conclusions of several recent studies. This novel approach of examining the transient response to a forcing on short time scales may be useful in various other outstanding problems.

Variability in QBO Temperature Anomalies on Annual and Decadal Time Scales

2021 ◽  
Vol 34 (2) ◽  
pp. 589-605
Author(s):  
Zane Martin ◽  
Adam Sobel ◽  
Amy Butler ◽  
Shuguang Wang
Keyword(s):  
Time Scales ◽  
Lower Stratosphere ◽  
Boreal Winter ◽  
Quasi Biennial Oscillation ◽  
Tropical Tropopause Layer ◽  
Temperature Anomalies ◽  
Tropical Tropopause ◽  
Tropical Troposphere ◽  
The Relationship ◽  
Biennial Oscillation

AbstractThe stratospheric quasi-biennial oscillation (QBO) induces temperature anomalies in the lower stratosphere and tropical tropopause layer (TTL) that are cold when lower-stratospheric winds are easterly and warm when winds are westerly. Recent literature has indicated that these QBO temperature anomalies are potentially important in influencing the tropical troposphere, and particularly in explaining the relationship between the QBO and the Madden–Julian oscillation (MJO). The authors examine the variability of QBO temperature anomalies across several time scales using reanalysis and observational datasets. The authors find that, in boreal winter relative to other seasons, QBO temperature anomalies are significantly stronger (i.e., colder in the easterly phase of the QBO and warmer in the westerly phase of the QBO) on the equator, but weaker off the equator. The equatorial and subtropical changes compensate such that meridional temperature gradients and thus (by thermal wind balance) equatorial zonal wind anomalies do not vary in amplitude as the temperature anomalies do. The same pattern of stronger on-equatorial and weaker off-equatorial QBO temperature anomalies is found on decadal time scales: stronger anomalies are seen for 1999–2019 compared to 1979–99. The causes of these changes to QBO temperature anomalies, as well as their possible relevance to the MJO–QBO relationship, are not known.

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