page_title: Weather buoy
section_title: Types
hierarchical_section_title: Weather buoy / Types
caption_attribution_description: English: A diagram showing the various types of moored buoys used by the National Climatic Data Center, United States
context_page_description: Weather buoys are instruments which collect weather and ocean data within the world's oceans, as well as aid during emergency response to chemical spills, legal proceedings, and engineering design. Moored buoys have been in use since 1951, while drifting buoys have been used since 1979. Moored buoys are connected with the ocean bottom using either chains, nylon, or buoyant polypropylene. With the decline of the weather ship, they have taken a more primary role in measuring conditions over the open seas since the 1970s. During the 1980s and 1990s, a network of buoys in the central and eastern tropical Pacific Ocean helped study the El Niño-Southern Oscillation. Moored weather buoys range from 1.5–12 metres in diameter, while drifting buoys are smaller, with diameters of 30–40 centimetres. Drifting buoys are the dominant form of weather buoy in sheer number, with 1250 located worldwide. Wind data from buoys has smaller error than that from ships. There are differences in the values of sea surface temperature measurements between the two platforms as well, relating to the depth of the measurement and whether or not the water is heated by the ship which measures the quantity.
context_section_description: Weather buoys range in diameter from 1.5–12 metres (5–40 ft). Those that are placed in shallow waters are smaller in size and moored using only chains, while those in deeper waters use a combination of chains, nylon, and buoyant polypropylene. Since they do not have direct navigational significance, moored weather buoys are classed as special marks under the IALA scheme, are coloured yellow, and display a yellow flashing light at night.
  Discus buoys are round and moored in deep ocean locations, with a diameter of 10–12 metres (33–39 ft). The aluminum 3-metre (10 ft) buoy is a very rugged meteorological ocean platform that has long term survivability. The expected service life of the 3-metre (10 ft) platform is in excess of 20 years and properly maintained, these buoys have not been retired due to corrosion. The NOMAD is a unique moored aluminum environmental monitoring buoy designed for deployments in extreme conditions near the coast and across the Great Lakes. NOMADs moored off the Atlantic Canadian coast commonly experience winter storms with maximum wave heights approaching 20 metres (66 ft) into the Gulf of Maine.
   Drifting buoys are smaller than their moored counterparts, measuring 30–40 centimetres (12–16 in) in diameter. They are made of plastic or fiberglass, and tend to be either bi-colored, with white on one half and another color on the other half of the float, or solidly black or blue. It measures a smaller subset of meteorological variables when compared to its moored counterpart, with a barometer measuring pressure in a tube on its top. They have a thermistor (metallic thermometer) on its base, and an underwater drogue, or sea anchor, located 15 metres (49 ft) below the ocean surface connected with the buoy by a long, thin tether.
caption: Types of moored buoys used by the National Data Buoy Center