On the Analysis of Long-range Me eorological Phenomena into Stationary Oscillations

[摘要] The aim of this paper is to analyse a spontaneous oscillation into some stationary one. A complex oscillation can be showed as the composition of some stationary ones. Let the position and the time be s and t respectively. We consider a function of them: F means the deviation of f from its own average value in case of t=const.Here we put: F(s, t)=S(s)T(t)+δ(s, t) and make the product of T(t) (function of time) and S(s) (function of position) nearest to F (s, t), which means to make Σt Σs δ2 the least. Then we find that S and T show the form and the change of intensity of the prevailing stationary oscillation from the statistical point of view. The same procedure may be applied to the analysis of residual δ(s, t), and we can get the secondary stationary oscillation. The same is the case with the thirdly and the other higher order oscillations. S(s) is determined by the following simultaneous equations: These equations are easily solved by the successive approximation. T(t) is derived from S and F by the following equation: S(s) calculated by the above equations determines a nodal line of oscillation. But we hope to find the real position of it. Let it be s=_??_. _??_ is described as follows: Then, S-_??_ gives the real form of stationary oscillation. As some examples of this method we have analysed the following three cases:(a) barometric pressure field of, the Far Fast in January, 1941.(b) potential temperature field of the Far East in January, 1941.(c) barometric pressure field of the Northernhemisphere in January, 1937. We have succeeded to calculate till the sixth oscillation. The first and the second stationary oscillations show a progressive one moving eastward in middle latitudes. On the other hand the third and the fourth components oscillate from north to south. The first oscillation of potential temperature varies sharply or slackly in gradient between north and south. Its variatlon of T(t) resembles with the case of the first oscillation pressure. It may be seen from the last analysis (c) that the first oscillation of pressure over the Northernhemisphere acts to develop or weaken the high pressure areas on the Eurasian and the North American continent and low pressure areas in the neighbourhood of Iceland and Aleutians. This may be regarded as the same oscillation with the first one in case of (a), Far East only.

[学科分类] 大气科学