Reply #16: What you are seeing

[Fovea]

is the effect of disruption of air that is super saturated.
The addition of energy from the contrail causes a sudden shift of state as the vapor condenses like super cooled water freezing when it hits the ground. Note that you see this more at evening, when atmospheric mixing is greatest.

As to it being used to effect the albedo of the planet, I dont see that as a useful strategy (how much, how often... it relies on many factors.)