Geographia Polonica (1997) vol. 70

Long-term Variability in the Number of Days with Precipitation in Kraków in Relation to Circulation Patterns

Robert Twardosz

Geographia Polonica (1997) vol. 70, pp. 77-88 | Full text

Abstract

The paper analyses long-term variability in the number of days with precipitation in Kraków in relation to changes in atmospheric circulation. Data on annual, semi-annual and seasonal numbers of days with precipitation > 0.1 mm in the 1814-1995 period and data on days with precipitation >1.0 mm and > 10.0mm for the years 1850-1995 were used. For precipitation threshold values, averages, maxima, minima, standard devia-tions and variability coefficients are presented. For the 1874—1995 series, correlation coefficients between the number of days with precipitation and the index of cyclonicity - C, determined on the basis of the classification of circulation types proposed by T. Niedźwiedź, are calculated. It was found that the number of days with precipitation >0.1 mm and > 1.0 mm shows significant positive trends in the cold half of the year and in the winter period, and negative trends in the warm half of the year and in the summer period. The variation in the number of days with precipitation >0.1 mm and >1.0 mm shows significant correlation with fluctuations of the C index which is most pronounced in the cold half of the year.

Keywords: variability, trends, number of days with precipitation, atmospheric circulation, Kraków

Robert Twardosz [r.twardosz@iphils.uj.edu.pl], Department of Climatology, Institute of Geography of the Jagellonian University ul. Grodzka 64, 31-044 Kraków, Poland