Visibility Sensors: Testing to Operations For NOAA's PORTSŪ

The NOAA/National Ocean Service (NOS) Physical Oceanographic Real-Time System (PORTSŪ) provides real-time water level, currents and meteorological data for navigation aid in twenty major ports and harbors. In response to PORTSŪ user requests for visibility data, the NOS began testing several varieties of visibility sensors for operations in a marine environment. Extensive testing, conducted in partnership with the FAA and the USCG, culminated in the selection of the Vaisala FS11 visibility sensor. The FS11 sensor uses traditional forward-scattering technology to measure the amount of optical scattering in a small volume of air between a transmitter and receiver. The first two visibility sensors were installed in the Mobile Bay PORTSŪ approximately 15 miles apart along the western shore in areas susceptible to fog formation. Real-time data from these sensors disseminate on the NOAA Center for Oceanographic Operational Products and Services PORTSŪ website every 6 minutes (www.tidesandcurrents.noaa.gov) . The successful integration of this new data type will result in improved navigation and will facilitate decision-making for port pilots in the Mobile Bay, especially during the winter months when patchy fog is more prevalent. Based on the expressed user need for visibility data to support operations in other ports, NOS is planning additional installations as part of the PORTSŪ program.