Anomalous Propagation of the Quasi-stationary Planetary Waves in the Atmosphere and Its Roles in the Impact of the Stratosphere on the East Asian Winter Climate
Anomalous Propagation of the Quasi-stationary Planetary Waves in the Atmosphere and Its Roles in the Impact of the Stratosphere on the East Asian Winter Climate
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DOI：
10.11867/j.issn.1001-8166.2009.03.0272
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发表时间：
2009-03
期刊：
影响因子：
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通讯作者：
Chengming Wen;Wei Ke
中科院分区：
文献类型：
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作者：
Chengming Wen;Wei Ke
东亚季风区受全球辽阔的海洋和大陆的双重影响，这种海陆热力对比和青藏高原的地形迫使东亚季风区产生强的行星尺度扰动，这些行星尺度扰动是准行星尺度的，它们是东亚季风区的主要扰动。利用再分析资料，主要从年际和季节内两个方面研究了异常行星波活动对东亚冬季气候的影响时间尺度。在年际时间尺度上，北方冬季行星波的两个波导存在反相振荡。一方面，这种年际振荡与北方环状模相互作用。另一方面，它对东亚气候异常产生影响。在低纬波导强冬季期间，西伯利亚高压减弱，东北、华北地区气温升高，弱低压期间则相反。结果还表明，平流层纬向风准两年振荡（QBO）对行星波活动与东亚冬季气候的年际关系有很强的调制作用，只有在QBO东风位相，行星波传播的年际振荡与东亚地区的气候异常密切相关，在季节内时间尺度上，准定常行星波活动的变化与平流层极涡的低频变化密切相关，结果表明平流层极涡异常可能对短周期行星波活动有向下的影响。平流层异常通过与行星波的相互作用向下传播，对对流层大气环流有明显的影响，由于平流层的变化一般具有较长的时间尺度，这种向下传播导致对流层的变化，该研究为东亚冬季短期气候异常提供了一种新的预测因子。
East Asian monsoon region is influenced by both the vast ocean and continent in the world.Strong disturbances with planetary scale are forced by this thermal contrast between ocean and continent and the topography of Tibetan Plateau.And these planetary scale disturbances are quasi-stationary.By using the reanalysis dataset the influences of anomalous planetary wave activities on the East Asian winter climate are studied mainly on the interannual and intraseasonal timescales.On the interannual timescale,two waveguides of planetary waves in the northern winter have anti-phase oscillation.On the one hand,this interannual oscillation has an interaction with the Northern Annular Mode.On the other hand,it exerts influence on the climate anomalies over East Asia.During the strong low-latitude waveguide winters,the Siberian high tends to wea and the temperature tends to increase over Northeast China and North China.The situation tends to be reverse during the weak low-latitude waveguide winters.The results also indicate that the relationship between the planetary wave activity and the East Asian winter climate on interannual timescale is strongly modulated by the tropical quasi-biennial oscillation(QBO) of zonal wind in the stratosphere.Only in the QBO easterly phase,the interannual oscillation of planetary wave propagation is closely related to the climate anomalies over East Asia.On the intraseasonal timescale,the variability in the quasi-stationary planetary wave activity is closely associated with the low frequency variation of stratospheric polar vortex.The results indicate that the anomalous polar vortex in the stratosphere may have a downward influence on the short-term climate in the troposphere via the interaction with the planetary waves.This downward propagation of stratospheric anomalies associated with polar vortex has an evident influence on the general circulation in the troposphere,and the influence is particularly significant over East Asia.Since the stratospheric variability generally has longer timescales and this downward propagation leads the variations in the troposphere,our research provides a new predictor for the East Asian winter short-term climate anomalies.