The Voluntary Observing Ship (VOS) program is an international initiative coordinated by the World Meteorological Organization (WMO) and the Intergovernmental Oceanographic Commission (IOC) of UNESCO. It involves the recruitment of merchant ships, research vessels, and other marine platforms to record and transmit real-time meteorological and oceanographic observations.
Overview and Objectives
The primary objective of the VOS program is to obtain environmental data from the world's oceans to support weather forecasting, maritime safety, and climate research. Because vast areas of the ocean are not covered by stationary weather stations or buoys, data provided by ships in transit are essential for accurate global weather models and storm warnings.
Participation and Methodology
Participation in the program is voluntary. National Meteorological Services (NMS) recruit ships from various nations to join the scheme. Once a ship is enrolled, it is typically provided with calibrated instruments (such as barometers, thermometers, and anemometers) and specialized software for data entry.
Observations are generally taken at standard "synoptic" hours (0000, 0600, 1200, and 1800 UTC). Key parameters recorded include:
- Atmospheric pressure and pressure tendency
- Wind speed and direction
- Air temperature and humidity
- Sea surface temperature
- Wave height and period
- Visibility and cloud cover
- Ice accretion or sea ice presence (where applicable)
Data Transmission
Modern VOS vessels transmit their observations via satellite communication systems (such as Inmarsat) or terrestrial radio frequencies. The data are formatted into standardized codes, such as FM 13 SHIP, and sent to a National Meteorological Center. From there, the information is distributed globally through the WMO Global Telecommunication System (GTS) for use by meteorological offices and researchers worldwide.
Historical Context
The origins of the VOS program trace back to the mid-19th century. In 1853, the First International Meteorological Conference was held in Brussels, led by Matthew Fontaine Maury of the U.S. Navy. The conference established a standardized method for recording marine observations in logbooks, laying the groundwork for international cooperation in maritime meteorology.
Importance to Science
VOS data are a primary source of long-term climate records over the oceans. They are used to validate satellite observations, monitor global warming trends, and provide "ground truth" for sea-level pressure and sea-surface temperature datasets. Despite the rise of automated satellite technology, the manual and automated observations from the VOS program remain a critical component of the Global Ocean Observing System (GOOS).
