任荣彩. 2012. 过去60年中3—5年时间尺度的强ENSO过程与平流层环流异常的滞后耦合及其机理[J]. 气象学报, 70(3):520-535, doi:10.11676/qxxb2012.043
过去60年中3—5年时间尺度的强ENSO过程与平流层环流异常的滞后耦合及其机理
Study of the lag-coupling between the 3-5 year timescale ENSO events and the stratospheric circulation in the past 60 years and its mechanism
投稿时间:2010-09-25  修订日期:2011-09-05
DOI:10.11676/qxxb2012.043
中文关键词:  3—5 a时间尺度, 强ENSO过程, 平流层环流异常
英文关键词:3-5 year timescale, Stronger ENSO events, Stratospheric anomalous circulation
基金项目:国家973项目(2010CB428603、2010CB950400)和中国科学院知识创新工程重要方向项目(KZCX2-YW-BR-14)
作者单位
任荣彩 中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室北京100029 
摘要点击次数: 3415
全文下载次数: 2568
中文摘要:
      基于1950—2009年60a月平均Nino3指数和NCEP/NCAR第一套等压面再分析资料,关注3—5 a时间尺度的强ENSO过程与平流层环流年际异常的时空联系及其机理,通过对此期间出现在3次持续强ENSO阶段中的11次3—5 a时间尺度的强ENSO过程的诊断表明,平流层环流的年际尺度异常与3—5 a时间尺度的强ENSO循环过程密切耦合。极夜急流强度趋于在ENSO暖/冷峰值之后减弱/加强,最大异常值多滞后ENSO峰值约1/4周期(接近1 a),出现在ENSO峰值之后的下一年冬季;且3—5 a时间尺度的ENSO峰值愈强,滞后约1/4周期出现的热带外平流层纬向风的年际异常也愈强;平均而言,这种年际时间尺度的耦合关系,也对实际的季节尺度平流层极涡振荡的强度和性质有显著的调制作用。进一步研究这种滞后耦合关系与年际时间尺度的行星波活动异常的联系发现,在暖ENSO峰值所在的当年冬季,对流层高层被强迫出年际时间尺度的太平洋-北美(PNA)型异常环流,而与冷ENSO峰值相对应的是相反的太平洋 北美异常型;这种太平洋-北美型与平流层热带外地区的行星波1波的发展相联系;在ENSO峰值之后的下一年冬季,太平洋 北美型环流减弱但对流层高层的主要异常分布在中高纬度,多对应着平流层行星波2波的显著增强,与平流层极区最强的高度异常相联系。行星波活动所引起的经向动量通量和经向热量通量的辐合、辐散异常对平流层滞后异常响应的贡献,存在显著的阶段性差异,在不同的阶段两者可以共同起作用,也可以分别起作用。
英文摘要:
      By applying the monthly Nino 3 index and the NCEP/NCAR re-analysis data covering 60 years from 1950 to 2009, with focusing on the coupling relationship between the 3-5 year timescale stronger ENSO events and the inter-annual variability of the stratospheric circulation, the diagnosis on the 11 ENSO events belonged to 3 stronger ENSO periods are made and the results show that, the winter polar jet tends to anomalously weaken/strengthen after warm/cold ENSO events, and the maximum anomalies appear in the next winter after the ENSO peak; this delayed coupling relationship in the timescale of 3-5 year is particularly consistent during the 3 stronger ENSO periods, and the stronger the ENSO peak, the stronger the stratospheric polar jet anomalies that appear about 1/4 period later. On average, this inter annual timescale response of the stratospheric circulation to ENSO has significant effect on the intensity or polarity of the seasonal timescale Polar Vortex Oscillation. Further diagnosis on the anomalous planetary wave activity in the inter-annual timescale shows that, in the concurrent winter of ENSO peak, an inter-annual timescale PNA (Pacific North America) pattern is excited, while the anomalous PNA excited by cold ENSO is with opposite polarity to that by warm ENSO. The PNA pattern is related to the increasing in the planetary wave-number one in the extra-tropical stratosphere in the concurrent winter. In the next winter, the PNA decays and stronger anomalies exist largely in the mid-high latituds in the upper troposphere. Meanwhile, the planetary wave-number two in the stratosphere is significantly intensified, corresponding to the strongest anomalies of the polar vortex then. However, the contribution of the anomalous convergence of the meridional eddy heat flux and the momentum-flux exhibits quite distinct difference among the different periods. The two factors may contribute either jointly in some periods or separately in other periods.
HTML   查看全文   查看/发表评论  下载PDF阅读器
分享按钮