I was talking with an acquaintance about lightning, and we came up with opposite theories and predictions for the frequency of lightning over ocean.
My theory is that since seawater is a fluid riddled with ions, the charges can move to equalize with whatever field is applied to it; therefore it should take a much higher, much faster increase in the magnitude of cloud charge to cause the dielectric breakdown necessary for a strike--in other words, the clouds have to beat the ocean to the punch before it dissipates the increase. So I predict less frequent lightning over the ocean.
His theory is that the composition of the lower surface is irrelevant; it's the insulating effect of the air that contributes to favorable conditions for lightning generation. He predicts more or less equal frequency of lightning over land or sea.
Wikipedia bears out my prediction (sourced from NASA data):
According to the distribution of lightning page, strikes occur most frequently in the tropics, on land. What makes this possible? More importantly, which of us is right? ;)