1961–1990 high-resolution Northern and Central Italy monthly precipitation climatologies

摘要

Monthly Northern and Central Italy precipitationclimatologies, obtained by means of a procedure aiming at capturing thelocal dependence of precipitation on elevation, are presented. The procedureconsists in considering each cell of a high-resolution grid and in makinguse of the closest 15 stations in order to perform a weighted linearregression of precipitation versus elevation: the weights are determined bythe distances of the stations from the grid point and by the level ofsimilarity between the stations' cells and the considered grid cell in termsof elevation, slope steepness, slope orientation and distance from the sea.The study is based on a dataset of about 3200 1961–1990 monthly precipitationnormals. The performance of the procedure is evaluated by reconstructing themonthly precipitation normals of each station and by comparing them with thecorresponding observed values. Such comparisons are performed by means offive error estimators: the mean absolute error and the mean error, bothevaluated in absolute and relative form, and the root mean squared error.The mean absolute error is slightly more than 10 mm for the monthlyprecipitation, which turns out to be between 10% and 14% of themonthly precipitation.