北半球30hPa大气低频变化水平结构--遥相关的研究

TELECONNECTIONS IN THE HORIZONTAL STRUCTURE OF 30-HPA LOW-FREQUENCY OSCILLATION IN THE NORTHERN HEMISPHERE

摘要: 过去对大气遥相关的研究集中在对流层,特别是500hPa,为了对低频变化水平结构有深入的了解,有必要研究其在平流层中的表现。本文选择了能体现平流层动力学特征的30 hPa层,对其月平均及冬季每日的高度场展开了研究。结果表明:平流层大气同样存在着遥相关型,主要表现为冬半年极冠地区与中低纬的南北向跷跷板型及夏半年的单一正相关型。在冬季南北向跷跷板型的背景上,迭加着沿大圆路径走向的行星尺度波列:苏联(-)-北太平洋(+)-格陵兰岛(-),定义为SPG型。采用冬季的四种不同频率资料分析证明低频时间尺度资料构成相似的遥相关型,而由带通滤波资料得到的显著相关仅存在于极夜急流附近。本文还分析了冬季遥相关型的时间演变及冬季遥相关型与天气实体的联系。

Abstract: In this paper the teleconnection for the 30一hPa geopotential height in Norhern Hemisphere has been described. In winter it produces a meridional seesaw pattern between polar-cap and large areas at mid and lower latitudes. In summer it is positively correlated only. The meridional seesaw pattern is superimposed on in January by a planetary wave train of Soviet Union-Pacific-Greenland (SPG) type along the great circle route. Further more,The dependence of, winter teleconnection on time and the relation of winter teleconnection and synoptic reality are discussed.