Influence of clouds on spatial distribution of conductivity in the atmosphere

In the paper, we examine the atmospheric part of the global electric circuit. When studying large-scale currents in the atmosphere flowing from the ionosphere to the ground, the ionosphere and Earth’s surface can be considered as ideal conductors with high accuracy. These currents are determined by the ground-ionosphere voltage and the spatial distribution of conductivity in the atmosphere. We employ a one-dimensional model of atmospheric electric fields and currents in which currents are assumed to be nearly vertical. Then it is possible to reduce the spatial distribution of conductivity to longitude and latitude distribution of conductivity of atmospheric columns. By integrating the conductivity over the entire Earth surface, we obtain the total conductivity of the atmosphere. Inside clouds, air conductivity decreases due to the ion attachment to water drops. Using available data on decrease in local conductivity within individual clouds, we analyze the effect of cloud density in latitude, longitude, and height on geographical distribution of conductivity and total conductivity of the atmosphere. By the example of 2009, it is shown that cloudiness reduces the total conductivity of the atmosphere by 20 %. Its variations during the day and year are so small that the model fair-weather electric field varies only by 2 % due to cloudiness. Judging by the results obtained, the influence of clouds on atmospheric conductivity does not explain the diurnal and seasonal cycles of the fair-weather electric field strength (Carnegie diagram).