Effects of global circuit downward current flow on atmospheric dynamics: Modeling of relevant cloud microphysics

Much previous work shows large-scale winter atmospheric dynamic changes responding on the day-to-day timescale to inputs to the global circuit that produce regional changes in the downward current density Jz. Recent work shows surface pressure and geopotential height changes within the polar vortices responding to overhead ionospheric potential changes, separately due to solar wind changes and changes in the electrified cloud generators at low latitudes. A new analysis shows the North Atlantic Oscillation responding on the day-to-day timescale to changes in the solar wind speed associated with precipitation of relativistic electrons into the mesosphere and stratosphere; consistent with previous observations of atmospheric vorticity changes. The latter responses occur with Jz changes in winters with moderate to high stratospheric and mesospheric aerosol loading, and imply non-negligible column resistances in those regions at those times. They are also consistent with Boberg and Lundstedt's determination of NAO changes on the winter-to-winter timescale responding to solar wind electric field changes. A proposed mechanism involves electro-scavenging and electro-anti-scavenging of cloud condensation nuclei and ice nuclei by cloud and haze droplets, which are charged with space charge generated by the flow of Jz through gradients of conductivity. To facilitate modeling of such processes, parameterizations of new simulations of charge modulated scavenging of nuclei have been made. The simulations include diffusion as well as gravitational and phoretic forces. The parameterizations can be used in cloud microphysical models evaluating storm invigoration, cloud cover, and precipitation changes related to Jz.