抄録
When making a hydrological map, it is necessary to evaluate the accuracy of the obtained map and specify it on the map. The author has studied the spatial correlation of monthly precipitation and proposed a method of expressing the accuracy of monthly precipitation map by using spatial correlations.
The calculation of spatial correlation is done among all the stations over the area. The accuracy is measured by the maximum value which is smaller than any actual correlation coefficients between all the neighboring observation stations.
The data used in the analysis are the monthly precipitations observed in the northern and the middle parts of the Kanto District from January 1961 to December 1970. Iso-lines of spatial correlations of monthly precipitation are shown in Figs. 1_??_5. There are some distinctive features in the patterns of iso-lines. The iso-lines of 0.90 and 0.95 are not always circular but slender except the case of iso-line map for Tokyo. The area of the closed iso-lines of spatial correlations is large in the middle part of the Kanto Plain, and small in the area adjacent to the mountainous area. It is important to arrange the observation stations by the synthetic consideration of spatial correlations of the precipitation.
