Relationships between atmospheric positive electric charge densities and gas bubble concentrations in the Baltic Sea

Simultaneous measurements of bubble density in the sea subsurface and positive ions in the lower atmosphere were performed in the Baltic Sea in the summer of 1999. Bubbles in two size ranges, around 27 and 100 μm, were measured acoustically. Airborne positive charge was measured with a Gerdien instrument. Observed concentrations of air ions varied from 60 cm−3 up to 600 cm−3. The relative role of bubbles and wind speed on the positive air ion concentrations over the brackish water of the Baltic Sea is discussed. The parameters of a model of a log-log dependence between charge concentration and bubble density are calculated. The correlation functions between time series of concentrations of positive charges over the sea and gas bubbles averaged over a depth range from 0.4 to 4 m and wind speed are presented. There was zero lag between the cross-correlation maxima of charge and bubbles, but there was a phase lag of one and a half hours between charge and wind speed.