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GCOS Atmospheric Surface ECV: Pressure Over the Land: Over land, the WMO WWW/GOS surface synoptic observing network (~10 000 stations) provides the major in situ observations of the following ECVs: Temperature, Air Pressure, Precipitation, Water Vapour, Surface Radiation (e.g., sunshine duration, solar irradiance) and Wind Speed and Direction. Included in this network is the global baseline GSN. The GSN comprises about 1000 stations that have been selected from the full available network based on past performance and their contribution towards a global representation of the climate system. The operators of GSN stations, in particular, are encouraged to fully meet the GCMPs for observation and for data exchange, where possible for all surface ECVs. The GSN data can be analysed to yield basic indicators of the global climate system, and also provide benchmark locations for higher-density regional and national networks. Important contributions to such regional networks are the WMO WWW Regional Basic Climatological Networks (RBCN, total ~3000 station subset of the WWW/GOS surface synoptic network), established in all regions of the world including Antarctica to support regional representations of the climate system. The GSN is implemented through cooperation among NMSs and the international community; through the AOPC working with the WMO Commission for Basic Systems (CBS) and WMO Regional Associations (RA); and through capacity-building initiatives such as those of the WMO Voluntary Cooperation Programme and the GCOS Cooperation Mechanism. The AOPC, in cooperation with the WMO CBS, carries out detailed analysis of the problems in the receipt of GSN observations and works with national services to resolve them. Over the Ocean: In addition to the land-based observations of pressure, pressure data over the ocean are required from sensors mounted on drifting buoys (also in the sea-ice areas of the Arctic and Antarctic), on VOS including the higher-quality VOSClim subset, on parts of the Tropical Mooring Network, and on the Reference Buoy Network. Many of these measurements have been operational over the last 30 years; the data are exchanged and inserted into the operational meteorological WWW system and are subject to quality-control procedures at the time of data acquisition and again at the analysis centres. Of particular concern is that surface pressure sensors are not included on all drifting buoys. Although there has been a significant improvement in recent years, particularly in the extra-Tropics where surface pressure measurements are most useful, the OOPC, working through the Joint Technical Commission for Oceanography and Marine Meteorology (JCOMM), and the national agencies that deploy drifting buoys, should endeavour to ensure that surface pressure sensors are included as a component of the suite of instruments on all buoys deployed. [ECV Matrix Main Page] [About the ECV Matrix] [Reference Documents] [Contact] |
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