雪尔德白兰森（Hildebrandscon）爱克斯纳(Fxner)及贺(sirGilbertT.Walker)诸氏均先后证明在地球上相去甚远二地之天气,常可以统计方法而求得其相互之关系。诸氏研究之结果发现有二大波动(Oscillation)存在,即北大西洋波动(North Atlantic Oscillation)与北太平洋波动（North Pacific Oscillation）是也。其後贺高氏更发现第三波动,称之日南波动(Southern Oscillation)。

The research was suggested by Sir Gilbert T. Walker and carnied out under his supervision. The object is (1) to find out the relationship between the rainfall of China of the rainy season and world weather; and (2) to find some regression for-mulae for foreshadowing China rainfall of the rainy season. Walker’s shorter method has been used for the calculation of the correlation coefficients and his critoria have been applied for testing the reliability of the coeffieients.