 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 . 
