Hybrid Approach to Delineation of Homogeneous Regions for Regional Precipitation Frequency Analysis

• Published in: Journal of Hydrology and Hydromechanics 2009-12, Vol.57 (4), p.226-249
• Main Authors: Gaál, Ladislav, Szolgay, Ján, Lapin, Milan, Fasko, Pavol
• Format: Article
• Language: English
• Subjects: calendar year; Climate change; Cluster analysis; homogeneous regions; homogénne regióny; kalendárny rok; l-moments; l-momenty; maxima of 1-to-5 day precipitation amounts; maximálne 1- až 5-denné úhrny zrážok; Precipitation; regional frequency analysis; Regions; regionálna frekvenčná analýza; slovakia; slovensko; Statistical methods; teplý/chladný polrok; warm/cold sea-son; zhluková analýza
• ISSN: 0042-790X; 1338-4333
• DOI: 10.2478/v10098-009-0021-1

Hybrid Approach to Delineation of Homogeneous Regions for Regional Precipitation Frequency Analysis Regional frequency analysis of heavy precipitation amounts based on the estimation of the parameters of a regional distribution function using [L]-moments is adopted for the specific geographical-climatological settings of Slovakia. The paper focuses on the first step of the regional [L]-moment algorithm ([Hosking, Wallis], 1997), which is the delineation of homogeneous regions. Objective and process-based logical pooling techniques are used to form homogeneous pooling groups of rainfall gauging stations for regional frequency analysis of [k]-day precipitation amounts ([k] = 1 to 5 days). Even though the delineation of homo-geneous regions by means of objective methods is generally accepted and recommended in the literature, it is concluded here that such a pooling of similar sites should not be carried out automatically in precipitation analysis. Instead, a combination of physical/geomorphological considerations and objective methods should be preferred.