Factors influencing Northern Hemisphere winter mean atmospheric circulation anomalies during the period 1960/61 to 2001/02
Factors influencing Northern Hemisphere winter mean atmospheric circulation anomalies during the period 1960/61 to 2001/02
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1960/61年至2001/02年北半球冬季平均大气环流异常影响因素
DOI：
10.1002/qj.1947
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发表时间：
2012
影响因子：
8.9
通讯作者：
T. Kunz
中科院分区：
文献类型：
--
作者：
R. Greatbatch;G. Gollan;Thomas Jung;T. Kunz
利用应用于ECMWF模式的松弛技术，研究了热带、平流层以及观测到的海表温度和海冰（SSTSI）对1960/61年至2001/02年期间北半球冬季平均环流异常的影响。在年际时间尺度上，热带强烈影响太平洋部分，但也影响北大西洋部分，尽管影响较弱。平流层在年际时间尺度上对北大西洋涛动（NAO）有影响，但对太平洋扇区的影响较小。将观测到的SSTSI添加到热带弛豫运行中，通常会改善模式在年际时间尺度上的性能，但会降低/增强模式捕捉太平洋/大西洋扇区42年趋势的能力。虽然将平流层放宽到再分析中无法捕捉整个42年期间的趋势，但平流层在1965 - 1995年期间对NAO指数的上升趋势有影响，但与以前的研究相比幅度减小。尽管在所有实验中，我们只能解释半球趋势幅度的30%，但我们发现热带的影响对两个时间段和两个部门的趋势都很重要。版权所有©2012英国皇家气象学会
Influences from the Tropics, the stratosphere and the specification of observed sea surface temperature and sea‐ice (SSTSI) on Northern Hemisphere winter mean circulation anomalies during the period 1960/61 to 2001/02 are studied using a relaxation technique applied to the ECMWF model. On interannual time‐scales, the Tropics strongly influence the Pacific sector but also the North Atlantic sector, although weakly. The stratosphere is found to be influential on the North Atlantic Oscillation (NAO) on interannual time‐scales but is less important over the Pacific sector. Adding the observed SSTSI to the tropical relaxation runs generally improves the model performance on interannual time‐scales but degrades/enhances the model's ability to capture the 42‐year trend over the Pacific/Atlantic sector. While relaxing the stratosphere to the reanalysis fails to capture the trend over the whole 42‐year period, the stratosphere is shown to be influential on the upward trend of the NAO index from 1965 to 1995, but with reduced amplitude compared to previous studies. Influence from the Tropics is found to be important for the trend over both time periods and over both sectors although, across all experiments, we can account for only 30% of the amplitude of the hemispheric trend. Copyright © 2012 Royal Meteorological Society