Moored buoys are considered to be the “weather sentinels” of the sea and are deployed by countries all over the world. Larger moored buoys are used near shore, while smaller drifting buoys are used farther out at sea. For the U.S., a significant network of buoys (and coastal stations) is operated and maintained by the National Oceanic and Atmospheric Administration’s (NOAA’s) National Data Buoy Center (NDBC). The buoys are deployed in coastal and offshore waters from the western Atlantic to the Pacific Ocean around Hawaii, and from the Bering Sea to the South Pacific. Moored buoys provide standard, hourly observations of wave height and period, but some buoys can also measure and transmit data on barometric pressure, air and sea surface temperatures, as well as wind speed, direction, and gustiness. Even the direction of wave propagation can be measured on many of NOAA’s buoys.
The buoys can face rough weather and are anchored using anything from chains in shallow waters to heavy-duty, polypropylene rope in deeper waters. The buoys are serviced every two years to try to keep up with corrosion. Maintenance work is mostly performed by the NDBC, although the U.S. Coast Guard may repair some of the more remote buoys.
Recently, the NDBC expanded and enhanced its existing network of buoys with the addition of hurricane buoys in the western North Atlantic Ocean. These buoys can measure winds, waves, and barometric pressure, as well as air and sea temperatures. Data gathered can then be used to determine hurricane formation or dissipation, the extent of wind circulation, and center location. The hurricane buoys are more robust than other weather buoys because they contain an internal back-up system and will allow NOAA to attain more data in an area where hurricanes frequently occur.
Weather buoys are an incredibly valuable part of the hurricane warning system. Surveys of meteorologists have shown about 40% of the National Weather Service's (NWS) marine warnings and advisories are based, at least in part, on NDBC's meteorological data.