The turbulent electrode effect as influenced by interfacial ion transfer

Abstract

The turbulent electrode effect at the earth's surface is treated as an exchange of small and large ions between the atmosphere and an aerodynamically rough boundary. Results of past experimental and theoretical work on the interfacial transfer of gases and small particles between the surface layer and the ocean or vegetated land are reviewed to establish the correct boundary conditions. The conclusion that the conductivity does not vanish at the effective lower boundary implies that charge separated by the conduction current there must be accounted for. This leads to the development of a new physical model of the electrode effect which is applied over the ocean, ignoring aerosol attachment, and over land, assuming that attachment predominates over recombination of small ions. The strong‐turbulence limit of Willett (1978) can still be exploited in many circumstances to yield a simplified, linear, mathematical description of charge convection in the “electrode layer.” It is concluded that this layer produces upward convection currents with magnitudes between 60 and 90% of the total fair‐weather current density over a wide variety of conditions. The effects of “surface radioactivity” appear to be small unless the ionization rate is enhanced by a large factor within the plant canopy.