Advances in Science and Research www.adv-sci-res.net 1992-0628 1992-0636 3 8th EMS Annual Meeting and 7th European Conference on Applied Climatology 2008 2009 10.5194/asr-3-73-2009 http://www.adv-sci-res.net/3/73/2009/ http://www.adv-sci-res.net/3/73/2009/asr-3-73-2009.html http://www.adv-sci-res.net/3/73/2009/asr-3-73-2009.pdf 73 78 2009-04-29 1961–1990 high-resolution Northern and Central Italy monthly precipitation climatologies M. Brunetti G. Lentini M. Maugeri maurizio.maugeri@unimi.it T. Nanni C. Simolo J. Spinoni Istituto per le Scienze dell'Atmosfera e del Clima, via Gobetti 101, 40129 Bologna, Italy Dipartimento di Fisica, via Celoria 16, 20133 Milano, Italy Monthly Northern and Central Italy precipitation climatologies, obtained by means of a procedure aiming at capturing the local dependence of precipitation on elevation, are presented. The procedure consists in considering each cell of a high-resolution grid and in making use of the closest 15 stations in order to perform a weighted linear regression of precipitation versus elevation: the weights are determined by the distances of the stations from the grid point and by the level of similarity between the stations' cells and the considered grid cell in terms of elevation, slope steepness, slope orientation and distance from the sea. The study is based on a dataset of about 3200 1961–1990 monthly precipitation normals. The performance of the procedure is evaluated by reconstructing the monthly precipitation normals of each station and by comparing them with the corresponding observed values. Such comparisons are performed by means of five error estimators: the mean absolute error and the mean error, both evaluated in absolute and relative form, and the root mean squared error. The mean absolute error is slightly more than 10 mm for the monthly precipitation, which turns out to be between 10% and 14% of the monthly precipitation. Brunetti, M., Maugeri, M., Monti, F., and Nanni T.: Temperature and precipitation variability in Italy in the last two centuries from homogenised instrumental time series, Int. J. Climatol., 26, 345–381, 2006. Brunetti, M., Lentini, G., Maugeri, M., Nanni, T., Simolo, C., and Spinoni, J.: Estimating local records for Northern and Central Italy from a sparse secular temperature network and from 1961–1990 climatologies, Adv. Sci. Res., 3, 63–71, 2009. Daly, C., Neilson, R. P., and Phillips, D. L.: A statistical–topographic model for mapping climatological precipitation over mountainous terrain, J. Appl. Meteorol., 33, 140–158, 1994. Daly, C., Gibson, W. P., Taylor, G. H., Johnson, G. L., and Pasteris, P.: A knowledge-based approach to the statistical mapping of climate, Clim. Res., 22, 99–113, 2002. Daly, C.: Guidelines for assessing the suitability of spatial climate data sets, Int. J. Climatol., 26, 707–721, 2006. Daly, C., Halbleib, M., Smith, J. I., Gibson, W. P., Doggett, M. K., Taylor, G. H., Curtis, J., and Pasteris, P. A.: Physiographically-sensitive mapping of temperature and precipitation across the conterminous United States, Int. J. Climatol., 28, 2031–2064, doi:10.1002/joc.1688, 2008. Frei, C. and Schär, C.: A precipitation Climatology of the Alps from high-resolution rain-gauge observations, Int. J. Climatol., 18, 873–900 (also available at the website http://www.map.meteoswiss.ch/sop-doc/rr_sop/FreiSchaer1998.pdf), 1998 . Frosini, P.: La carta della precipitazione media annua in Italia per il trentennio 1921–1950, in: Precipitazioni medie mensili ed annue e numero di giorni piovosi per il trentennio 1921–1950, Pubblicazione n 24, Istituto Poligrafico dello Stato, Servizio Idrografico – Ministero Lavori Pubblici, Fascicolo 13, 1961 (in Italian). Servizio Idrografico – Ministero dei Lavori Pubblici: Precipitazioni medie mensili ed annue e numero di giorni piovosi per il trentennio 1921–1950, Istituto Poligrafico dello Stato, 1–12c, 1957 (in Italian). Schwarb, M.: The Alpine precipitation climate: evaluation of a high-resolution analysis scheme using comprehensive rain-gauge data, ETH PhD Thesis n 13911, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland, 131 pp., 2000.