rsync is an open source utility that provides fast incremental file transfer. rsync synchronizes directory stucture between two machines. To run rsync over SSH , provide the -e flag in the args.
rsync -ave ssh email@example.com:/home/user/mydropzone/ /home/user/mydropzone
By Default, rsync will not remove files/folders from the destination folder if they were removed on source since last rsync. To remove files/folders that are no longer present at remote, user --delete flag.