The atmospheric electrode effect over snow

The atmospheric electrode effect is treated both in the turbulent and non-turbulent cases. For the non-turbulent case it is shown by geometrical considerations that field-free regions near the ground act as an effective ion supply reducing the electrode effect, except in winter when the snow forms a smooth ground. The equations with turbulence are linearized and solved analytically assuming that the charged aerosol remains uniformly distributed owing to its long time of recovery from turbulent fluctuations. Data from continuous measurement of the difference of positive and negative conductivity, which is proportional to the space charge density, show good agreement with theory in both cases, provided that the air is stable near the ground when the positive conductivity is less than about 6 fS m⁻¹ during fair weather.