Each site has a pop up alert that can be turned on or off for each campus and is used to notify visitors of announcements. You can edit these alerts by going to Content > Sections > "Alert Popup" and "Arlington - Alert Popup"

You can edit the image, content, and where the button links (or you can leave out the button entirely and let the user click out of the alert using the X in the top right corner).

To turn the popup off, there is a checkbox called "Hide Popup" that will hide the alert from displaying.