Good luck! I would start with training her to 'speak' and then 'quiet'. Leave it command works also with something that they see. If there is nothing to see or hear, then I would remove the dog from the area they are barking. Window coverings, shades, any barrier you can come up with will help.
We have a porch that our dogs LOVE, but if they bark a lot, they are made to come inside. It is a on going battle!