Rainfall variations in the Galilee (Israel), I. Variations in the spatial distribution in the periods 1931-1960, and 1951-1980

Mean monthly rainfall from different stations in the Galilee (northern Israel) for the periods 1931-1960 and 1951-1980, have been correlated with longitude, latitude and altitude of each station. A seasonal pattern of the explained variance (r²) by each of the variables has been found. At the beginning of the rainy season, the rainfall is correlated strongest with the longitude of the stations, during the main rainy season with the altitude and at the end of the rainy season with the latitude of the stations. In the latter period (1951-1980) the correlation with latitude is weaker than in the first period (1931-1960). The decrease in the correlation may be attributed to a shift in the depressions' tracks in the Eastern Mediterranean and to cloud seeding. A trend surface analysis of the isohyetal orientation in each month reflects the same seasonal pattern; a shift from a mainly N-S orientation at the beginning of the rainy season, to a mainly E-W or even ESE-WNW orientation at the end of it.