摘要
先从纬向平均的角度出发，以地转平衡关系为基础，从纬向平均纬向风分布得到中、低纬度的位势高度场在赤道附近存在极小值，将其他纬度上位势高度相对于此的差（仿纬向偏差而称其为经向偏差）不但可以表示副热带高压带脊线位置与用纬向风零线的表示一致，还可以表示其范围及强度。结合纬向平均纬向风零线和经向偏差，对气候平均的副热带高压带以及其季节变化和年际变化等三维特征进行了分析。结果表明，对流层中，随高度升高，气候平均的副高带脊线向赤道靠拢，强度减弱，范围缩小。副高带脊线的季节变化和年际变化均很明显，并且表现出对流层整层的同时的变化特征。对流层中上层副高带的强度，夏半球强于冬半球，北半球的变化较南半球大。尤其在北半球夏季，副高带在对流层中、上层随高度升高而增大；其脊线的移动也表现出一定的跳跃性。这些结果表明对副热带高压带的研究，从整体上进行是必要的。
The zero line of zonal wind can depict the ridge of subtropical high belt, but it cannot reveal the strength of the belt. In order to analyze the three-dimensional structure of the high belt, other methods or indices are necessary. In this paper, from the viewpoint of zonal mean and based on geostrophic balance, it is deduced that there is a minimum value of geopotential height near the equator along east-west Wind distribution. With the zonal mean of geopotential height along the equator on each isobaric tropospheric layer as a criterion. the difference between the geopotential heights along other latitudes and the criterion are defined as the meridional deviation. The maximum of the meridional deviation cannot only show the ridge of the high belt which is also represented by the zero line of zonal wind, but also show the strength of the belt. With both the zero line of zonal mean of zonal wind and meridional deviation. the three-dimensional structure of climatological subtropical high belt, the seasonal and inter-annual variation of subtropical high belt are analyzed. Results show that the ze- ro line of zonal mean of zonal wind and the connected line of meridional deviation maximum are cov- ered and both of them are the ridge of subtropical high belt. With the increment of height. the ridge of subtropical high belt comes closer to the equator. and the strength is weaker and the range is narrower. There is apparently seasonal and inter-annual variabilities of subtropical high belt ridge and the whole layer exhibits concurrent variations. As for the stl-ength of subtropical high belt, over the lower troposphere. the summer hemisphere is stronger than the winter hemisphere. and the tluctuation is much stronger in the Northern Hemisphere than that in the Southern Hemisphere. Especially in the summer of the Northern Hemisphere, the strength of subtropical high belt strengthens with height increase in the middle and higher troposphere and the movement of the ridge jumps to some extent. The above analysis disclose
出处
《大气科学》
CSCD
北大核心
2000年第5期577-584,共8页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金!49635170
资助项目49805003和49905002
关键词
经向偏差
副热带高压带
副高带脊线
三维结构
meridional deviation. subtropical high belt. subtropical high belt ridge
