Interannual variations of the seasonal march in the Southern Hemisphere stratosphere for 1979-2002 and characterization of the unprecedented year 2002
Interannual variations of the seasonal march in the Southern Hemisphere stratosphere for 1979-2002 and characterization of the unprecedented year 2002
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DOI：
10.1175/jas-3333.1
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发表时间：
2005-03-01
影响因子：
3.1
通讯作者：
Yoden, S
中科院分区：
文献类型：
--
作者：
Hio, Y;Yoden, S
利用NCEP-NCAR再分析资料，研究了1979-2002年南半球平流层季节变化的年际变化特征，并与23年进行了对比。对平流层平均纬向风的多重经验正交函数分析和基于主模主成分的合成分析表明，平流层平均纬向风的年际变化主要表现为极夜急流的早期或晚期减速，这与平流层低层时间平均上升通量的变化有很好的相关性。平流层下部较强的波动活动与急流较早的“下移”有关。平流层平均纬向风的合成差异可以追溯到9月和10月的对流层下部。这些特征与南半球环模的变化是一致的，但平流层和对流层维持环模变化的主要扰动不同。一些散点图显示了2002年的极端情况。这与其他23年的波动趋势相去甚远，但2002年的大偏差与其他年份的波动趋势是一致的，但其极端性质除外。
Dynamical features of the interannual variations of the seasonal march in the Southern Hemisphere stratosphere are investigated with the NCEP-NCAR reanalysis dataset from 1979 to 2002, and the unprecedented year 2002, in which a major stratosphere sudden warming occurred, is characterized by comparing it with the other 23 yr.A multiple empirical orthogonal function analysis of the stratospheric mean zonal wind and a composite analysis based on the principal component of the leading mode show that the interannual variations are characterized by early or late deceleration of the polar-night jet, which is well correlated with the variation of a time-averaged upward Eliassen-Palm (EP) flux in the lower stratosphere. The stronger wave activity in the lower stratosphere is associated with the earlier "shift down" of the jet. The composite difference of the stratospheric mean zonal wind can be traced down to the lower troposphere in September and October. These features are consistent with the variations of the Southern Hemisphere annular mode, although the main disturbance to maintain the variations is different between the stratosphere and troposphere. Some scatter diagrams show the extreme situation of the year 2002. It is far from the cluster of the other 23 yr, but the large deviation in 2002 is consistent with the tendency of the fluctuations in the other years except for its extreme nature.