The investigators will examine a mechanism that may increase the rate of atmospheric ice formation through contact nucleation of supercooled droplets. The mechanism involves electrical forces between charged contact nuclei resulting from the evaporation of charged droplets at cloud tops and charged, supercooled water droplets at cloud tops. Charging results from conductivity gradients at cloud boundaries due to vertical fair weather currents in the global electric circuit. This mechanism may be a significant source of ice in the atmosphere. If the mechanism is proven to be a source of ice it may mediate physical connections between solar processes and terrestrial weather and climate. Such connections are suggested by various statistical studies, but identification of a causal link has proved to be elusive. The main effort is to calculate details of the mechanism, and to incorporate the mechanism into a model of global electricity. This model will permit an assessment of meteorological effects.
