Abstract
Cross correlation coefficients between the 500 mb contour height at about 50°N 140°E and those at the twenty five points in its vicinity, were calculated from the data of the Januaries 1948-1952 and the features of the correlation fields were investigated. The contour heights at the several points having the relatively stable correlation were selected as predictors and the 24-hour predictions of the 500 mb contour height at about 50°N 140°E were performed by the method of linear regression. When time lag τ is relatively large, the correlation coefficients at above twenty five points become small and unstable, and so cross correlation coefficients of lag 1-10 days between the 500 mb contour height at about 50°N 140°E and those at many points over the northern hemisphere, were calculated and the behaviours of the distributions of correlation coefficients were discussed. At the same time, the theoretical correlation field was obtained from the linearized vorticity equation and compared with the actual correlation fields, and the features of the correlation field were discussed by the method of spectrum analysis. Some considerations on the nonlinear system were also made.
