Final answer:
Air traffic controllers are responsible for notifying the tower when the visibility changes at the official weather observation point.
Step-by-step explanation:
In aviation, the responsibility for notifying the tower of changes in visibility at the official weather observation point lies with air traffic controllers (ATC). ATC personnel play a crucial role in ensuring the safety and efficiency of air traffic operations. They closely monitor weather conditions, including visibility, and promptly communicate any significant changes to the tower. This real-time information allows the tower to make informed decisions, such as adjusting runway usage or providing updated weather information to pilots. The collaboration between ATC and the tower is vital for maintaining safe and smooth operations in the dynamic environment of aviation.