Correlation coefficients between the monthly mean temperature of Sapporo in July and 500mb heights in preceding months have been investigated. The 500mb heights used in this work are read off from the monthly mean charts of previous November, January, March and May for the period from 1946 to 1960 at 99 mesh points.
As a result of screening calculation, high correlations to the temperature of Sapporo have been found on the 500mb chart for previous November in the vicinity of the Caspian Sea and for January in the south of the Lake Baikal with correlation coefficients of +0.74 and +0.72 respectively. While, in March and May, correlations are not so high as in November or January. A multiple correlation coefficient between the July temperature and the 500mb heights at the center of these high correlations in November and January is 0.87. This suggests that the temperature in July over North Japan is governed tatistically by the behaviour of the general circulation of previous November and January.
Furthermore, the following two relations have also been discovered. One is that the 500mb height in November over the Caspian Sea is related to the formation of the Okhotsk Sea High in the following July. The other is that the 500mb height in January in the south of the Lake Baikal is related to the anticyclone of the middle latitude over the Northwest Pacific in July.
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