说明：  线性相关 求逐月异常序列x(n,12)和y(n,12)(n是年)相同月份之间的滞后超前nt年的相关系数rt(-nt:nt,12)，其中nt最大的滞后或超前时间（单位：年）。
(Linearly related to demand monthly abnormal sequence x (n, 12) and y (n, 12) (n is the year) ahead of the same month lag between the years of the correlation coefficient nt rt (-nt: nt, 12), in which nt the largest lag or lead time (unit: years).)