Relationships between occurrence of high precipitation and atmospheric circulation in Poland using different classifications of circulation types

Abstract

The main objective of this study is to analyse the relationship between atmospheric circulation and high precipitation in Poland, using selected classifications of circulation types. Daily precipitation totals from 48 synoptic stations and three classifications of circulation types ( Litynski, 1969; Niedzwiedz, 1981, 2008; Ustrnul, 1997) were used. These classifications were described and compared. The relationships between high precipitation and atmospheric circulation were analysed by (i) determining those circulation types that favour the occurrence of high precipitation, (ii) analysing the spatial differentiation of the probability of high precipitation events for chosen cyclonic circulation types and (iii) the usefulness of the classifications to analyse relations between high precipitation in Poland and atmospheric circulation was assessed. Any study of relations between atmospheric circulation and climate elements demands a preceding detailed assessment of the usefulness of a given classification for a defined problem. The results for relations between high precipitation occurrence and circulation depend on the rules applied to classify circulation types. Ustrnul’s classification seems to be best suited to study the relationship between heavy precipitation and circulation in the southern part of Poland. This result is based on two methods, the range of probabilities for high precipitation in each circulation type of a given classification (Pr diff) and the Brier skill score (BSS). The Niedzwiedz classification mainly produces very good results in central southern Poland where its probability range is clearly wider than elsewhere. Both methods seem to be less useful to study the relationships between high precipitation and circulation in northern Poland. Litynski’s classification delivers a greater role of the cyclonic types in forming high precipitation, but no definite prevailing type can be identified at many of the stations. When analysing relations, regional classification of circulation should be applied rather than macro-scales ones.