Seasonal Variations in the Southern Hemisphere Storm Tracks and Associated Wave Propagation
Seasonal Variations in the Southern Hemisphere Storm Tracks and Associated Wave Propagation
复制标题
南半球风暴路径的季节变化和相关波浪传播
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
Franchito
中科院分区：
文献类型：
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作者：
V.;Brahmananda Rao;C. A.M.;DO Carmo;Sergio;H.;Franchito
Abstract Seasonal variations in the Southern Hemisphere (SH) storm track characteristics and associated wave propagation are studied using 19 years of NCEP–NCAR gridded data. It is found that the SH storm track is strongest in the austral autumn season and weakest in spring. The characteristics of wave packets are studied by computing 1-point lag correlation maps with unfiltered meridional wind at 300 hPa. It is found that the eastward group velocities of waves are much higher than the phase velocities in the transition seasons. This shows that the downstream development occurs throughout the year and is a basic feature of upper-tropospheric waves in the midlatitudes of the SH. This extends previous studies made for winter and summer seasons. Based on the indices that show wave coherence and correlation maps, it is found that the pathways in the transition seasons split into two branches east of Australia, in a way similar to what happens in the zonal wind distribution.
