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Voluntary Observing Ships
Some 40 WMO Members operate voluntary observing ships and/or ocean weather stations. Traditionally these ships have measured and reported atmospheric and sea surface conditions needed for meteorological forecasting. Data are reported in the WMO Ship Code format by a variety of communications methods ranging from satellite retransmissions to ship to shore radio. Once ashore the data are transmitted on the GTS at frequent intervals. The data and appropriate meta data are also recorded on board in paper or electronic logbooks for subsequent processing into climatological data sets. Variables observed include dry-bulb temperature, dew-point temperature, sea temperature, air-sea temperature difference, visibility, weather, wind direction and speed, pressure, cloud, and waves
The ships are recruited by National Meteorological Centers. This program depends heavily on the WMO network of Port Meteorological Officers (PMOs) who liaise with the ships and manage the operation. For more details see the VOS page in GOSIC.
National Centers Collecting Surface Observations Logs
The VOS data flow includes a delayed mode flow for ships' logbooks of surface meteorological observations. Under the Marine Climatological Summaries Scheme (MCSS) the data are digitized by the national meteorological service which recruited the ship and are sent to two Global Collecting Centres (GCCs). The GCCs undertake QC and then distribute the data to eight Responsible Members which archive the data and provide both the data and products to users on request. At least minimum QC is applied by the national meteorological services. The GCCs and Responsible Members also apply QC.
Port Meteorological Officers (PMOs)
WMO has an international network of around 200 Port Meteorological Officers (PMOs). In addition to helping to recruit suitable ships, the PMOs maintain, calibrate and often supply or replace instruments. They provide relevant literature, stationery, computer software, and train ships’ officers to make and record the observations. When the ship returns to port the PMOs collect the logbooks or electronic logs, consult with the ships personnel on problems noted either at sea or with previous data, and re-supply the ship for the next trip. The PMOs are the heart of the VOS operation playing a major role in maintaining the necessary good will on both sides for a successful operation.
Global Collecting Centers (GCCs)
The approximately 40 Member who operate voluntary observing ships are divided approximately between two Global Collecting Centers located in Germany and the UK. The GCCs receive the data, digitize and reformat it where necessary, undertake additional processing and QC, and then distribute the data to eight Responsible Members for archiving and development of regional products.
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Responsible Members for Climate Products and Summaries
The Marine Climatological Summaries Scheme was established with the objective of producing monthly, annual, and decadal climatological statistics and charts for the oceans beginning with 1961. In this scheme the oceans and seas are divided into areas of responsibility and eight Members (called "responsible Members") have assumed responsibility to prepare marine climatological summaries for these areas. These Members are: Germany, Hong Kong, India, Japan, Netherlands, the United Kingdom, the Russian Federation, and the U.S.A. The responsible Members receive surface observations from the Global Collecting Centers. Summaries are prepared, both for ocean weather stations and for selected representative areas, and include data on dry-bulb temperature, dew-point temperature, sea temperature, air-sea temperature difference, visibility, weather, wind direction and speed, pressure, cloud, and waves. The Responsible Members also archive the data for future users, and provide the data and products on request.
Monitoring Centers for VOS Data Quality
Several weather services operated by WMO Members participate in a scheme to monitor VOS data and feed back information on data problems to ship operators. To accomplish this monitoring , comparisons of the real-time VOS weather observations with the predictions of numerical weather prediction models are carried out routinely by several national weather centres around the world. The monthly mean bias and scatter between individual ship observations and the model fields are used to identify ships that are reporting poorly or have instruments that require recalibration or replacement. This information is fed back to ships with significant scatter or bias in their observations via the PMO network.
Log Book Data and Meta Data
Content: Surface observations and meta data
Format: National or international paper or electronic formats of convenience
Frequency: End of voyage
Availability: Only nationally.
Reason: For conversion to standard format and forwarding to international MCSS.
Inspection, Assistance, Problems, Supplies
Content: The PMOs supply material, advice, training, and consultation as required to maintain the observing program of the ship.
Format: N/A
Frequency: As required
Availability: N/A
Reason: .Maintain instruments, train observers, collect log books with observations, consult on data problems.
Processed Log Book Data and Meta Data
Content: Digitized surface observations and supporting meta data.
Format: International Marine Meteorological Tape format, International Marine Meteologogical Punch Card Format, or other agreed format.
Frequency: Quarterly
Availability: To others by bilateral agreement.
Reason: For MCSS program.
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