Geographia Polonica (2009) vol. 82, iss. 1, pp. 5-20 | Full text
The principal aim of this paper is to analyze the trends of the multi-annual course of the selectedcharacteristics of extreme precipitation, snow cover and atmospheric thunderstorms in the secondhalf of the twentieth century in Poland. The results of these investigations show that in Poland it is onlypossible to determine a weak decreasing trend of extreme precipitation events in the S and especially inthe SW part of the country. In northern Poland, opposite, although similarly weak, trends have also beenobserved. It is assumed that the most essential features of long-term changeability of extreme precipitationinclude a higher than average number of days with extremely high precipitation during the 1960sand 1970s, a distinctly lower frequency of such days during the 1950s, 1980s and in the fi rst half of the1990s. In Poland it is possible to distinguish four broad homogenous areas in terms of the long-termchanges in the occurrence of extreme precipitation events. There is considerable regional differentiationwhen it comes to the occurrence of thunderstorms in Poland, and their long-term changeability does notshow any clear trends. Only three stations have determined a weak increase in the number of thunderstormsduring the last 120 years. In some stations, an increase in the number of days with thunderstormsduring the winter seasons was also observed. There were no signifi cant trends in extreme snow coverin Poland. The periods that contained large and small areas of extreme snow cover thickness occurredalternately. Since the winter season 1987/88, the area of extremely thin snow cover has remained at arelatively high level.
Ewa Łupikasza, Department of Climatology, Faculty of Earth Sciences, University of Silesia, Będzińska 60, 41-200 Sosnowiec, Poland
Zuzanna Bielec-Bąkowska, Department of Climatology, Faculty of Earth Sciences, University of Silesia, Będzińska 60, 41-200 Sosnowiec, Poland
Małgorzata Falarz, Department of Climatology, Faculty of Earth Sciences, University of Silesia, Będzińska 60, 41-200 Sosnowiec, Poland