Dog keeps barking at outside noises

[Feir]

You could try distracting here when she barks or growls, like clap your hands to make a noise that will stop thinking about what is bothering her, this works well unless the clapping scares her and makes her more jumpy.
Maybe try to get her to sit and just stroke her and talk in a calm voice until she feels safe, it's like comforting her but sometimes this can be like you're reassuring her that it's ok to growl or bark.

Try either of those, if one doesn't work then the other should, depends how your dog interprets your actions.