VOS (Voluntary Observing Ship)

A Voluntary Observing Ship is a merchant vessel that records and transmits marine weather observations as a volunteer under the WMO VOS scheme, a program running since the 1850s. Officers report wind, air and sea surface temperature, pressure, cloud, visibility, and present weather, increasingly through automated weather stations, and many VOS also drop XBT probes along set routes for upper-ocean temperature. Reports flow onto the WMO Global Telecommunication System for numerical weather prediction and into the ICOADS climate archive. The VOS fleet, several thousand ships, gives surface marine coverage along trade routes that fixed buoys and research vessels leave unsampled.