 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 ) . 
