The relationship between altitude of meteorological stations and average monthly and annual precipitation

The aim of this study was to prove that altitudinal variability of average monthly and annual precipitation is better summarised when the altitude observed within a radius of several kilometres around a meteorological station is taken into consideration, instead of the altitude of the station itself. The use of the variable Z′, which combines the altitude of the closest mountain with its distance from the station, is compared against the use of altitude alone in simple linear and multiple quadratic regression equations for the altitudinal interpolation of precipitation over Greece. The data-set comprised precipitation observations from 516 meteorological stations. The comparison between the two variables is discussed on the basis of the resulting determination coefficients (R2) and standard errors of estimate (S). For all seasons, except summer, it was found that the variable Z′ improves the predictive ability of the regression equations, thus showing its potential for further use in interpolation procedures.