Precipitation pattern analysis in the Tiber River basin (central Italy) using standardized indices

• DOI: 10.1002/joc.3549
• Publication Date: 2012-07-13T22:32:56Z
• Authors: Emanuele Romano; Elisabetta Preziosi
• Keywords: Trend analysis

ABSTRACT This study analyses the precipitation pattern in Tiber River basin (central Italy) to determine trends, possible change points, periodicity and relationships with global climate indices, such as North Atlantic Oscillation ( NAO ) index. The dataset is composed of daily rainfall time series, recorded at 21 102 different sampling stations, from 1952 2007. following quantities were analysed both an annual seasonal scale: cumulative precipitation, number rainy days, mean intensity, maximum days needed reach a given percentage precipitation. To compare series collected stations along quantities, standardization procedure based on normal inverse function computed best‐fit probability distribution was applied. standardized each station regionalized by kriging. Trends using Mann–Kendall test, points determined algorithm singular spectrum analysis. signals evaluated cross‐wavelet results show decreasing trend (−8%) mainly because winter (−16%). appears be related decrease days. A significant point trends identified mid‐1980s. Conversely, those indices intensity (mean precipitation) do not trends. analysis performed annual/winter indicates existence four coherent periodic periods approximately 3, 4, 8 15 years. Copyright © 2012 Royal Meteorological Society