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Stopa-Boryczka M.,Zaklad Klimatologii | Boryczka J.,Zaklad Klimatologii | Kossowska-Cezak U.,Zaklad Klimatologii | Wawer J.,Zaklad Klimatologii
Przeglad Geofizyczny | Year: 2011

The presented paper deals with cold and warm waves in yearly course of air temperature. These waves were analysed on the basis of 60-year (1951-2010) mean values from meteorological station Warsaw Okȩcie. Investigation refers to cold waves in May ("Ice Saints"), "European monsoon" in June, autumnal warming (in Poland called "old woman summer") as well as to verification of Polish proverb dealing the air temperature in December 4th (Barbara) and December 25th (Christmas). Air temperature cycles, i.e. periods, amplitudes and phases, were calculated by using method of "regression sinusoid". Authors stated that 15,2-18,3 day cycles occurred in every months: about 15 days in January and November, about 16 days in March, April, May, August, September and October, about 17 days in June and December, about 18 days in February and July. The cold and warm waves are a result of interference of several days cycles in monthly course of the daily mean temperature and of several years cycles in multiannual course of the monthly mean temperature. The cold and warm waves are described by deviations (rests) ei, of measured temperature values Ti from regression sinusoid of multiannual yearly course.

The paper answers questions about the scale, frequency, timing and extent of anomalously wet periods, both seasonal and annual, in the Polish Carpathian Mountains and in their foreland, during the period 1881-2010. For the purpose of the study anomalously wet periods (AWPs) were defined as those when precipitation totals were equal to or greater than the top quartile plus 1.5x of the interquartile gap H (P≥Q75% + 1.5H). During the 130 years covered by the study, there were 62 anomalously wet seasons (AWS) and 25 anomalously wet years (AWY). Most AWPs were recorded at one station only, which suggests a strong local that influence in addition to circulation-related circumstances. The scale and the geographical extent of winter and summer AWSs tended to be smaller than those of spring and autumn with the ratio of two stations on average in the former to three stations in the latter case. The last of the studied decades, 2001-2010, had the greatest number of the AWY at 40% of all. The highest absolute AWS count was recorded at stations in a western section and in higher-altitude section of the south-east. The highest surpluses over the long-term average appear in all seasons (below 300% of the average). The AWS with the largest spatial coverage occurred in spring of 2010 at 10 stations and in autumn of 1931 and 2007 at nine stations each. It was found that AWSs were more frequent in the west of the area (up to seven at Wisla), which is explained by the mostly western circulation in the moderate climate zone bringing in humid air masses from over the Atlantic Ocean.

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