Add some automatic water cannon to the fence aimed at the top. Being blown that far off and down—they wouldn’t be climbing back up any time soon.
Water? No.
FIRE!
Use a flamethrower.
You can even use it in a non-lethal form.
You shoot the flame so it hits the fence (assuming non-flammable construction) to get it really hot. Do this before anyone is on the fence. Periodically sweep the fence with flame (random timer). The fence will be way too hot for anyone to climb.
Now if someone wants to “end it all” via the flame fence, that’s their problem.