@misc{Wibig_Joanna_Coldwaves_2009,
 author={Wibig, Joanna and Podstawczyńska, Agnieszka and Rzepa, Marcin and Piotrowski, Piotr},
 volume={82},
 number={1},
 copyright={Rights Reserved - Free Access},
 address={Warszawa},
 journal={Geographia Polonica},
 howpublished={online},
 year={2009},
 publisher={IGiPZ PAN},
 language={eng},
 abstract={The daily minimum and maximum temperatures at nine stations in Poland were used in an analysis of the occurrence of coldwaves, where these are defined as days with temperatures exceeding selected thresholds (tmin ≤ -20°C, tmin ≤ -15°C and tmax ≤ -10°C) in the period 1951-2006. Cold nights occurred more often than very cold days and nights but the mean lengths of waves of cold nights were similar – lasting a little more than 2 days on average. The frequencies of extremely cold days revealed a slight, but statistically non-signifi cant downward trend. The occurrence of coldwaves was associated with high-pressure systems over Central Europe and with blocking episodes, but it was always linked with a thick layer of cold air.},
 type={Text},
 title={Coldwaves in Poland – frequency, trends and relationships with atmospheric circulation},
 URL={http://www.rcin.org.pl/igipz/Content/55500/PDF/WA51_74827_r2009-t82-no1_G-Polonica-Wibig3.pdf},
 keywords={extremly low temperature, trend, Sen's slope, least squares method, Poland},
}