The zonal index, version for Central Europe (called ‘for Poland’), was proposed by Lityński. He calculatedthe pressure difference between latitudes 40° and 65°N on the zone 0-35°E. This paper presents thecharacteristics of the zonal index based on Lityński’s concept and the NCEP/NCAR grid data. A statisticallysignificant increase (1948-2016) occurs in mean values of the zonal index for winter and for the entire year,as well as in the standard deviation and 99 percentile of zonal index. The annual course of the zonal indexis evident.
Marek Nowosad [firstname.lastname@example.org], Maria Curie-Skłodowska University Faculty of Earth Science and Spatial Management al. Kraśnicka 2 cd, 20-718 Lublin: Poland