 = Weather buoy = 
 
 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 <unk> <unk> . 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 <unk> . Moored weather buoys range from 1 @.@ 5 metres ( 4 @.@ 9 ft ) to 12 metres ( 39 ft ) in diameter , while drifting buoys are smaller , with diameters of 30 centimetres ( 12 in ) to 40 centimetres ( 16 in ) . 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 . 
 
 = = History = = 
 
 The first known proposal for surface weather observations at sea occurred in connection with aviation in August 1927 , when <unk> <unk> stated that " weather stations along the ocean coupled with the development of the seaplane to have an equally long range , would result in regular ocean flights within ten years . " Starting in 1939 , United States Coast Guard vessels were being used as weather ships to protect transatlantic air commerce . 
 During World War II The German Navy deployed weather buoys ( <unk> See — <unk> ) at fifteen fixed positions in the North Atlantic and <unk> Sea . They were launched from U @-@ boats into a maximum depth of ocean of 1000 <unk> ( 1 @,@ 800 metres ) , limited by the length of the anchor cable . Overall height of the body was 10 @.@ 5 metres ( of which most was submerged ) , surmounted by a mast and <unk> aerial of 9 metres . Data ( air and water temperature , atmospheric pressure and relative humidity ) were encoded and transmitted four times a day . When the batteries ( high voltage dry @-@ cells for the <unk> , and nickel @-@ iron for other power and to raise and lower the aerial mast ) were exhausted , after about eight to ten weeks , the unit self @-@ <unk> . 
 The Navy Oceanographic Meteorological <unk> <unk> ( NOMAD ) buoy 's 6 @-@ metre ( 20 ft ) hull was originally designed in the 1940s for the United States Navy ’ s offshore data collection program . Between 1951 and 1970 , a total of 21 NOMAD buoys were built and deployed at sea . Since the 1970s , weather buoy use has superseded the role of weather ships by design , as they are cheaper to operate and maintain . The earliest reported use of drifting buoys was to study the behavior of ocean currents within the <unk> Sea in 1972 and 1973 . Drifting buoys have been used increasingly since 1979 , and as of 2005 , 1250 drifting buoys roamed the Earth 's oceans . 
 Between 1985 and 1994 , an extensive array of moored and drifting buoys was deployed across the equatorial Pacific Ocean designed to help monitor and predict the El Niño phenomenon . Hurricane Katrina capsized a 10 m ( 33 ft ) buoy for the first time in the history of the National Data Buoy Center ( <unk> ) on August 28 , 2005 . On June 13 , 2006 , drifting buoy <unk> ended its long @-@ term data collection of sea surface temperature after transmitting for 10 years , 4 months , and 16 days , which is the longest known data collection time for any drifting buoy . The first weather buoy in the Southern Ocean was deployed by the Integrated Marine Observing System ( <unk> ) on March 17 , 2010 . 
 
 = = Instrumentation = = 
 
 Weather buoys , like other types of weather stations , measure parameters such as air temperature above the ocean surface , wind speed ( steady and gusting ) , barometric pressure , and wind direction . Since they lie in oceans and lakes , they also measure water temperature , wave height , and dominant wave period . Raw data is processed and can be logged on board the buoy and then transmitted via radio , cellular , or satellite communications to meteorological centers for use in weather forecasting and climate study . Both moored buoys and drifting buoys ( drifting in the open ocean currents ) are used . Fixed buoys measure the water temperature at a depth of 3 metres ( 9 @.@ 8 ft ) . Many different drifting buoys exist around the world that vary in design and the location of reliable temperature sensors varies . These measurements are <unk> to satellites for automated and immediate data distribution . Other than their use as a source of meteorological data , their data is used within research programs , emergency response to chemical spills , legal proceedings , and engineering design . Moored weather buoys can also act as a navigational aid , like other types of buoys . 
 
 = = Types = = 
 
 Weather buoys range in diameter from 1 @.@ 5 metres ( 4 @.@ 9 ft ) to 12 metres ( 39 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 <unk> <unk> . Since they do not have direct navigational significance , moored weather buoys are classed as special marks under the <unk> scheme , are coloured yellow , and display a yellow flashing light at night . 
 <unk> buoys are round and moored in deep ocean locations , with a diameter of 10 metres ( 33 ft ) to 12 metres ( 39 ft ) . The aluminum 3 @-@ metre ( 10 ft ) buoy is a very rugged meteorological ocean platform that has long term <unk> . 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 . <unk> 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 centimetres ( 12 in ) to 40 centimetres ( 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 <unk> 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 <unk> ( metallic <unk> ) on its base , and an underwater <unk> , or sea anchor , located 15 metres ( 49 ft ) below the ocean surface connected with the buoy by a long , thin <unk> . 
 
 = = <unk> and maintenance = = 
 
 A large network of coastal buoys near the United States is maintained by the National Data Buoy Center , with deployment and maintenance performed by the United States Coast Guard . For South Africa , the South African Weather Service deploys and <unk> their own buoys , while the Meteorological Service of New Zealand performs the same task for their country . Environment Canada operates and deploys buoys for their country . The Met Office in Great Britain deploys drifting buoys across both the northern and southern Atlantic oceans . 
 
 = = <unk> to data from ships = = 
 
 Wind reports from moored buoys have smaller error than those from ships . <unk> the comparison of the two measurements are that NOMAD buoys report winds at a height of 5 metres ( 16 ft ) , while ships report winds from a height of 20 metres ( 66 ft ) to 40 metres ( 130 ft ) . Sea surface temperature measured in the intake port of large ships have a warm bias of around 0 @.@ 6 ° C ( 1 ° F ) due to the heat of the engine room . This bias has led to changes in the perception of global warming since 2000 . Fixed buoys measure the water temperature at a depth of 3 metres ( 10 ft ) . 
 
 