%0 Journal Article
%T Impact of atmospheric circulation on air temperature in Warsaw during months with extreme values of the NAO index (1951–2015)
%A Kossowska-Cezak, Urszula
%A Twardosz, Robert
%J Geographical Studies
%V 2018
%R 10.4467/20833113PG.18.004.8479
%N Issue 153
%P 69-87
%K Atmospheric circulation, NAO, air temperature, Warsaw
%@ 1644-3586
%D 2018
%U https://ejournals.eu/en/journal/prace-geograficzne/article/uwarunkowania-cyrkulacyjne-temperatury-powietrza-w-warszawie-w-miesiacach-o-skrajnych-wartosciach-wskaznika-nao-1951-2015
%X 
	In winter, western air masses arriving in Europe, including Poland, change the weather for relatively warmer, while an eastern advection tends to bring freezing temperatures. While the NAO provides a quantitative measure of this western advection, its relationship with air temperature is not always clear-cut. For this reason, this study characterises the circulation and thermal conditions over Poland depending on the sign and the value of the NAO index (NAO+, NAO–).
	The study is based on NAO values and winter (December – March) monthly temperature records in Warsaw spanning 65 years (1951–2015), as well as on the calendar of circulation types proposed by Lityński. A detailed analysis was performed looking at the top 10 months with the highest NAO+ and NAO–, as well as the top 10 months with the greatest positive and negative deviations from the long-term average air temperature (Dt). This selection was based on a premise that the months should largely coincide. The results, however, show certain deviations from previously established patterns in the influence of the NAO+/NAO– on air temperature in Poland.