Interannual Variations of Planetary Waves in the Southern Hemisphere Stratosphere
Interannual Variations of Planetary Waves in the Southern Hemisphere Stratosphere
复制标题
南半球平流层行星波的年际变化
DOI：
10.2151/jmsj.80.1013
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
I. Hirota
中科院分区：
文献类型：
--
作者：
Yasuko Hio;I. Hirota
利用1979 ~ 1998年20年NCEP/NCAR再分析资料，对南半球平流层行星波的年际变化进行了统计分析。本研究以瞬变斜压扰动的活动为重点，探讨行星波与对流层环流之间的动力耦合。通过对10 hPa月平均高度距平和对流层环流形势的分析，发现冬末（9月和10月）准定常行星波的年际变化具有纬向波数1的经向相移和波振幅的变化特征。平流层行星波的东（向西）移对应于对流层上层（300 hPa）纬向风的双急流（单急流）结构。另一方面，行星波振幅的变化与对流层上层纬向热通量的变化密切相关。这些结果被由平流层扰动谱组成的Eliassen-Palm通量诊断所加强，从而强调了对流层瞬变波对平流层行星波强迫的作用。
A statistical analysis is made of the interannual variability of stratospheric planetary waves in the Southern Hemisphere (SH) in late winter using NCEP/NCAR reanalysis data gathered over a 20 year period from 1979 to 1998. The study investigates the dynamical coupling between the planetary waves and the tropospheric circulation, by focusing on the activity of transient baroclinic disturbances. With the aid of EOF analysis applied to the 10 hPa monthly mean height anomalies and tropospheric circulation patterns, it is found that the year-to-year variation of quasi-steady planetary waves in late winter (September and October) is characterized by a longitudinal phase shift of zonal wavenumber 1 as well as by a variation in wave amplitudes. An eastward (westward) shift of the stratospheric planetary waves corresponds to a double-jet (single-jet) structure of the upper tropospheric (300 hPa) zonal winds. On the other hand, planetary wave amplitude variation is closely related to that of the meridional heat flux in the upper troposphere. These results are reinforced by the Eliassen-Palm flux diagnosis composed of the stratospheric EOF scores, and hence the effect of tropospheric transient waves on the forcing to the stratospheric planetary waves is stressed.