Winter Cyclone Vorticity Responses to Atmospheric Electricity: are they due to Charge Modulation of Aerosol Scavenging Causing Storm Invigoration?

Observations show winter storm vorticity responds to changes in the ionosphere-earth current density Jz, for disparate sets of external and internal inputs to the global electric circuit. These include Forbush decreases of the cosmic ray flux; minima in relativistic electron precipitation from the radiation belts; solar energetic particle events; solar wind electric fields in the polar caps; day-to-day thunderstorm current output changes. The vorticity changes appear to be due to storm invigoration (Rosenfeld et al., 2008), following changes in CCN concentration and size distribution due to electric charge modulation of aerosol scavenging (CMAS). New parameterizations from simulations of CMAS, that include Monte-Carlo treatment of aerosol diffusion, will be presented that may be used in models to test the hypothesized links. CMAS simulations of in-cloud scavenging show increases in small aerosol (notably CCN) concentration, due to long-range electrical repulsion that decreases the scavenging rates below the Brownian and phoretic rates. This is electro-anti-scavenging. For large and giant CCN increases in the scavenging rate are due to the short-range electrical image force, producing decreases in their concentration. This is electro-scavenging. Such effects are cumulative in a winter air-mass for one or more days, and in new deep cloud formation they decrease coalescence and initial production of rain, which increases the amount of liquid water carried above the freezing level. The consequent increase in release of latent heat of freezing invigorates the storm, and could account for the correlations of storm vorticity with Jz.