Krzysztof Fortuniak
Articles
Trends to changes in seasonal aspects of the climate in Poland
Geographia Polonica (2000) vol. 73, iss. 2, pp. 7-24 | 
Full text
Abstract
The study details the results of a search for changes in the annual rhythms for atmospheric pressure, air temperature and precipitation in Poland in the 19th and 20th cen-turies. In regard to atmospheric pressure, a reduction in the component amplitude of the annual cycle was noted. Values for annual amplitude of temperature exhibited a downward trend, as did data for the lengths of the seasons with temperatures below zero or in excess of 19°C. In turn, there was an upward trend for the duration of periods with temperatures several degrees above freezing or in the range 14-19°C. The most marked long-term upward trend to temperature was that noted for the five days 11-15 January, which have seen temperatures rise by as much as 4°C in the last decade. Annual courses for precipitation have demonstrated development of the half-year cyclical component responsible for relatively high winter pre-cipitation. Analysis of several time series has allowed for the deducing of decreasing con-tinentality of climate in Poland, a marked warming in the winter-spring period and a general weakening of seasonal contrasts regarding the climate.
Keywords: changes in air temperature and precipitation
[kkozuchowski1@wp.pl], Department of Environment Dynamics and Bioclimatology, University of Łódź, Lipowa 81, 90-568 Łódź, Poland
, Department of Environmental Dynamics and Bioclimatology, Faculty of Biology and Earth Science, University of Lodz Lipowa 81, 90-568 Łódź, Poland
[krzysztof.fortuniak@geo.uni.lodz.pl], Zakład Meteorologii i Klimatologii, Uniwersytet Łódzki, Lipowa 81, 90-568 Łódź, Poland
, Department of Meteorology and Climatology, Faculty of Biology and Earth Science, University of Lodz Lipowa 81, 90-568 Łódź, Poland
Regularities in the time series of mean daily temperature in Poland 1956-1990
Geographia Polonica (1999) vol. 72, iss. 1, pp. 143-155 | Full text
Abstract
Mean daily temperatures for 10 Polish meteorological stations from the period 1956-1990 were examined from the point of view of their periodicity. Classical spectrum estimation based on the Fourier transformation of the autocorrelation function was used. Particular attention was paid to similarities in power spectra for different stations. Two significant and well-marked periods are characteristic of time series for all the stations analysed: ~7.3 years and 196 days. Other common climatic fluctuations such as quasi-bien-nial, quasi-five-year or quasi-eleven-year oscillations were not found and neither were shorter cycles of the order of days or tens of days.
Keywords: Poland, temperature, spectral analysis, climate dynamic
[krzysztof.fortuniak@geo.uni.lodz.pl], Zakład Meteorologii i Klimatologii, Uniwersytet Łódzki, Lipowa 81, 90-568 Łódź, Poland
, Zakład Meteorologii i Klimatologii, Uniwersytet Łódzki, Lipowa 81, 90-568 Łódź, Poland