The solar and equatorial QBO influences on the stratospheric circulation during the early northern‐hemisphere winter

Kodera, Kunihiko

doi:10.1029/90gl02298

Cited by 65 publications

(43 citation statements)

References 11 publications

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“…The movement of the developing polar vortex anomaly to higher latitudes with time during the winter can also be seen in the present data, especially at midlatitudes (cf. Kodera, 1991;James and Dodd, 1996). Negative anomaly maxima of fv*+DF in the polar regions can be found near the latitude of the maximum mean zonal wind anomalies, so that the negative anomalies are likely to explain the difference found in the polar-night jet between the QBO phases.…”

Section: Wave Behaviormentioning

confidence: 87%

The Influence of the Equatorial QBO on the Northern Hemisphere Winter Circulation of a GCM

Niwano

Takahashi

1998

Journal of the Meteorological Society of Japan

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The influence of a simulated equatorial quasi-biennial oscillation (QBO) on the Northern Hemisphere winter was studied by analyzing output data from a general circulation model (GCM). The differences between the 7-50hPa equatorial QBO phases of the January-March (JFM) averaged zonal wind composite exhibit a weaker polar-night jet during the easterly phase of the equatorial QBO and a stronger polar-night jet in the westerly phase. The Eliassen-Palm flux of planetary waves is stronger and more convergent in the high latitude stratosphere for the easterly phase, while it exhibits similar characteristics in the mid latitude stratosphere during the westerly phase. These results are nearly consistent with observed results. Zonal wind deceleration anomalies are located slightly north of the tonal wind anomalies. It is likely that the JFM time-mean zonal wind anomalies develop from the small zonal wind anomalies during the early winter and propagate northward with time. The anomaly pattern in the troposphere coupled with that in the stratosphere reveals a tripole structure among equatorial, middle, and high latitudes, similar to the North Atlantic oscillation (NAO) pattern.

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Section: Wave Behaviormentioning

confidence: 87%

The Influence of the Equatorial QBO on the Northern Hemisphere Winter Circulation of a GCM

Niwano

Takahashi

1998

Journal of the Meteorological Society of Japan

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“…In spite of some attempts (e.g., Kodera, 1991) to explain this relation, the real mechanism of this relation continues to be unclear and awaits further investiga- March means of index g 1 and the equatorial zonal winds at 50 hPa and 30 hPa respectively. Running correlations are calculated using 3-year window width.…”

Section: Discussionmentioning

confidence: 99%

“…Following this assumption, the possibility of connection between the wintertime (January to March) variations of total ozone and the sunspot numbers at simultaneous moment in the QBO phase is investigated in the present study. This research is based on the results of Labitzke (1987), Labitzke and van Loon (1988, 1993, Kodera (1991Kodera ( , 1993, Kodera et al (1991), van Loon andLabitzke (1994), Soukharev (1997a) which were obtained by analysing a possible connection between the meteorological parameters in the winter stratosphere and the sunspot numbers when the data are grouped according to the phases of QBO. Thus, these authors have noted that during the phase of QBO there is positive correlation between the variations of temperature and geopotential heights in the winter polar stratosphere, and the solar activities.…”

Section: Introductionmentioning

confidence: 99%

The sunspot cycle, the QBO, and the total ozone over Northeastern Europe: a connection through the dynamics of stratospheric circulation

Soukharev

1997

Ann Geophysicae

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Abstract. The interaction between the factors of the quasi-biennial oscillation (QBO) and the 11-year solar cycle is considered as an separate factor in¯uencing the interannual January±March variations of total ozone over Northeastern Europe. Linear correlation analysis and the running correlation method are used to examine possible connections between ozone and solar activity at simultaneous moment the QBO phase. Statistically signi®cant correlations between the variations of total ozone in February and, partially, in March, and the sunspot numbers during the dierent phases of QBO are found. The running correlation method between the ozone and the equatorial zonal wind demonstrates a clear modulation of 11-y solar signal for February and March. Modulation is clearer if the QBO phases are de®ned at the level of 50 hPa rather than at 30 hPa. The same statistical analyses are conducted also for possible connections between the index of stratospheric circulation g 1 and sunspot numbers considering the QBO phase. Statistically signi®cant connections are found for February. The running correlations between the index g 1 and the equatorial zonal wind show the clear modulation of 11-y solar signal for February and March. Based on the obtained correlations between the interannual variations of ozone and index g 1 , it may be concluded that a connection between solar cycle ± QBO ± ozone occurs through the dynamics of stratospheric circulation.

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“…In both early and late winter months, they found deeper polar vortices and stronger polar night jets in the W than in the E. Labitzke (1982) showed that the polar lower stratosphere is colder in the W than in the E, and that major warmings do not occur in the W, except near the maxima of the solar cycle. Such interannual variability in the extratropical stratosphere associated with the equatorial QBO has been called the More recent observational studies (e.g., Labitzke, 1987;van Loon, 1988, 1992a;Labitzke and Chanin, 1988;Kodera, 1991) showed associations of the extratropical stratospheric circulation with the QBO and the 11-year solar cycle, though other authors (e.g., Salby and Shea, 1991) commented on the statistical significance of the associations. Labitzke (1987) and van Loon (1988, 1992a) showed that the north-polar temperature at 30 hPa has a correlation positive with the sunspot number in the W, but negative in the E.…”

Section: Introductionmentioning

confidence: 99%

Interannual Variability of the Northern Winter Stratospheric Circulation Related to the QBO and the Solar Cycle

Naito

Hirota

1997

Journal of the Meteorological Society of Japan

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A statistical study is made of the interannual variability of the northern winter stratospheric circulation in connection with the equatorial quasi-biennial oscillation (QBO) and the solar cycle, by using the 37-year stratospheric dataset of the Freie Universitat Berlin and the 31-year NMC global data.During the period 196263-197778, analyzed first by Holton and Tan (1980, referred to as HT), the polar-night jet is stronger in the W (westerly) than in the E (easterly), as was mentioned by Holton and Tan (1980). However, the difference between the W and the E is barely significant in 'the latter half period ' (197879-199394). When the whole period is classified into two groups defined as 'Min' and 'Max' with respect to the intensity of the 10.7-cm solar flux, it is clearly shown that the late-winter jet in the W is much stronger than in the E (the value of Student's t test exceeds 6) in the Min group, whereas it is no stronger in the Max group. The reason why the result from the HT period resembles that from the Min is probably because the HT period includes two solar minima and one maximum. In early winter, the circulation seems to be correlated with the QBO irrespective of the solar cycle. This difference between early and late winter suggests that the equatorial QBO influences the extratropical circulation in early winter and that the solar cycle modifies it in late winter.An extensive analysis of wave components is also made. The result from the Min is similar to that of the HT period, and the difference between the W and the E is larger than in the HT period. In late winter, the result from the Max is the inverse of the Min result.Finally, the occurrence of major warmings is shown to be related significantly to the QBO and the solar cycle. Such a relationship is clearly illustrated by plotting the occurrence of the major warming onto a 2D phase space of the solar flux and the equatorial wind.

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The solar and equatorial QBO influences on the stratospheric circulation during the early northern‐hemisphere winter

Cited by 65 publications

References 11 publications

The Influence of the Equatorial QBO on the Northern Hemisphere Winter Circulation of a GCM

The Influence of the Equatorial QBO on the Northern Hemisphere Winter Circulation of a GCM

The sunspot cycle, the QBO, and the total ozone over Northeastern Europe: a connection through the dynamics of stratospheric circulation

Interannual Variability of the Northern Winter Stratospheric Circulation Related to the QBO and the Solar Cycle

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