Fig. 7From: Characteristics of the atmospheric electric field and correlation with CO2 at a rural site in southern BalkansDifference between fair weather (FW)–potential gradient (PG) at Xanthi and the standard Carnegie curve (DPG). The DPG is presented as a percentage of the difference from the mean during different months and the time of the day for the period June 2011 to May 2012Back to article page