EVIDENCE OF MERIDIONAL MOTION IN THE SUMMER LOWER STRATOSPHERE ADJACENT TO MONSOON REGIONS
EVIDENCE OF MERIDIONAL MOTION IN THE SUMMER LOWER STRATOSPHERE ADJACENT TO MONSOON REGIONS
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DOI：
10.1029/95jd01263
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发表时间：
1995-08-20
影响因子：
4.4
通讯作者：
DUNKERTON, TJ
中科院分区：
文献类型：
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作者：
DUNKERTON, TJ
利用21年的降水探空资料和8年未初始化的欧洲中期天气预报中心（ECMWF）分析资料，描述了北半球和南半球夏季季风区附近大尺度环流的气候结构。在对流层上层和平流层下层，季风区的东、西两侧分别发生向赤道和向极地运动。结果表明，显著的经向速度（bbb10 - 1ms(-1)）穿透平流层下部，最大高度为50- 30mbar。最大经向速度与北半球夏季的亚洲季风有关。虽然这些运动在高度上是短暂的，但当行星波很小的时候，这些运动对于夏季平流层下层成分的水平输送是相对重要的。亚洲和墨西哥季风在这个季节离赤道足够远，靠近对流层顶断裂，在平流层-对流层（S/T）交换中起着重要作用。Chen（1995）的配套论文提供了北半球夏季“中上层世界”不可逆S/T交换的证据。
Twenty-one years of rawinsonde data were used together with 8 years of uninitialized European Centre for Medium-Range Weather Forecasts (ECMWF) analyses to describe the climatological structure of large-scale circulations adjacent to monsoon regions in northern and southern hemisphere summers. In the upper troposphere and lower stratosphere, equatorward and poleward motions occur on the eastern and western sides of monsoon regions, respectively. It is shown that significant meridional velocities (> 1 ms(-1)) penetrate the lower stratosphere up to a maximum height of 50-30 mbar. Largest meridional velocities are observed in connection with the Asian monsoon in northern summer. Although evanescent in height, these motions are relatively important for horizontal transport of constituents in the summer lower stratosphere, when planetary waves are otherwise small. Asian and Mexican monsoons in this season are displaced sufficiently far from the equator, in close proximity to the tropopause break, to have a significant role in stratosphere-troposphere (S/T) exchange. The companion paper by Chen (1995) provides evidence of irreversible S/T exchange in the ''upper middle world'' during northern summer.