A PRELIMINARY STUDY ON THE CHARACTERISTICS AND EVOLUTION OF MEAN MONTHLY CIRCULATION,II ULTRA-LONG WAVES
A PRELIMINARY STUDY ON THE CHARACTERISTICS AND EVOLUTION OF MEAN MONTHLY CIRCULATION,II ULTRA-LONG WAVES
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作者：
S. Wang
本文是作者研究近10年大气环流特征的第二部分。本文用四项调和分析方法，计算了55°N和35°N纬度沿着月平均500 mb高度的振幅和相位。从1951年到1960年。根据谱分布和相位角，讨论了大气环流的季节变化。主要结果如下:1.而同一纬度上的一、三次谐波的季节变化趋势则相反。另外,第1波或第3波振幅本身在55°N及35°N年变程也相反。也是相反的。二次谐波没有明显的季节性变化。（2）除55°N纬度处的二次谐波外，相位角的变化具有一定的季节性。（3）1951 - 1960年的光谱变化表明，季节变化年际间有所不同，但总的趋势是一致的。（4）过渡季节的谱特征明显不同于夏季和冬季的谱特征，因此，可以明确划分自然天气季节。季节的开始和结束以及季节的长度和特征每年都不一样。（5）我国的天气异常与北方半球超长波型有着密切的联系。这可以用1954年7月和1959年以及1957年2月和1960年的例子来说明。
This paper is the second report of a research project concerning the characteristics and evolution of the general circulation in recent ten years. The amplitude and the phase angle are calculated by means of 4-term harmonic analysis for the monthly mean 500mb hight along the 55°N and 35°N lat. from 1951 to 1960. According to the spectral distribution and phase angle, the seasonal variation of the general circulation is discussed. The conclusions are the following:(1)There is a pronounced seasonal course in the change of amplitudes of first and third harmonic. But this seasonal trend of the first and third harmonic at same latitude is opposite. The seasonal trend of the first or third harmonic at 55°N and 35°N lat. is also opposite. No clearly seasonal variation is revealed for the second harmonic.(2)The change of phase angle shows a regular seasonal course except for second harmonic at 55°N lat.(3)The variation of spectrum from 1951 to 1960 shows that the seasonal variation is different from year to year, but the general trend is the same for all years.(4)The characteristics of the spectrum of transitional seasons are clearly distinct from those of summer and winter, therefore the natural synoptic seasons may be clearly defined. The begining and ending as well as the length and character of the seasons vary from one year to another.(5)The weather anomaly in China has a close connection with the pattern of ultra-long waves in northern hemisphere. This may be shown by examples of July 1954 and 1959, as well as February 1957 and 1960.