ИСТИНА

This study concerns the effects of atmospheric boundary layer(ABL)diurnal evolution on the fair-weather atmospheric electricity.The approach used for computation of scalar concentration fields in turbulent flows may well provide new possibilities for atmospheric electricity problems.The modelfornon-stationary turbulent transportbased on a probability density function methodoffers someadvantages for quantitative estimatesof local perturbations in thefair-weatherelectric fieldcreated by space charges.The variations inthe atmospheric electricity associated with the ABL turbulent dynamics are shownto be significant in comparison with the variations attributed to the changes in global parameters. It is foundthatduring the ABL transition from night to daythe change inelectric fieldintensityat the earth’s surface more than twicecanonlybea consequence ofthe local change in the electrical conductivity.Thespace chargeresponse toredistribution of electrical conductivity is evaluated, which is due to development of convection in the ABL. It helps to shed light on the sunrise effect consisting in enhanced ground-level atmospheric electric field compared with thatusuallymeasuredin the nocturnal stably stratified boundary layer. This effect caused by variable turbulent mixing efficiency leads to occurrence of local daytime peak in the electric field, which is often observed around the globe but has not received a generally accepted explanation by now.