北半球30 hPa环流春季转变过程的诊断研究

利用1965—1986年30 hPa逐日高度、温度资料和月平均臭氧资料，对环流的春季转变过程进行了诊断研究。结果表明:50°N以北极冠地区高度场涡动方差E指数小于4×104（dagpm）2的初日可以作为30 hPa自然天气季节进入春节的近拟度量；冬末至早春环流在压、温和经、纬向风场方面均有显著变化；定常和瞬变涡旋动量、热量通量和通量辐散（合）的时-空变化特征明显；春季转变早、迟两类情况下极区平流层热源——臭氧在经向、纬向和垂直分布方面呈现异常。

A Diagnostic Study of the Transition of the 30 hPa Circulation in Northern Spring

Based on the northern 30 hPa daily altitude and temperature data for 1965—1986 and monthly mean ozone observations for 1958—1976, studies are conducted on the natural transitional process of the circulation from winter to spring by means of dynamic approach and statistical diagnostic analysis. Results are obtained as follows: (1) the first day on which the E index of eddy variance of the height field in the polar-cap area north of 50 oN is smaller than 4×104 (dagpm) 2 can be taken as an approximate measure of the beginning of spring for the natural season; (2) the circulation in the period from late winter to early spring experiences significant changes in the pressure, temperature, and zonal-meridional wind fields; (3) stationary and transcient vortex momentum, heat flux and flux convergence (divergence) undergo remarkable temporal-spatial variations; (4) in both the early and late transitions into spring, the heat source—ozone in the polar stratosphere shows zonal, meridional and vertical anomalies