Atmospheric Electric Parameters Around Days with Increased Number of Condensation Nuclei

Air conductivity and atmospheric electric potential gradient measured at Świder observatory (Poland) between 1965 and 1995 have been investigated around days with increased number of condensation nuclei (NCN). Data determined for the evening hours have been analysed by the superposed epoch method. Two groups of days with increased NCN were selected by distinguishing two different degrees of the increase (group 1: from 50% to 75%, group 2: >75%, as related to the actual monthly average of NCN). These days have been used as key days for independent superposed epoch analyses.