1. The WMO facilitates worldwide cooperation in the establishment of networks of stations for the making of meteorological observations as well as hydrological and other geophysical observations related to meteorology. Observing stations are operated by WMO Members according to agreed standards and recommended practices described in the WMO Regulatory Material, such as Technical regulations, WMO-No. 49 and its Annexes.
2. The WMO requirements for observational data are generally divided into three categories: global, regional and national. For example, surface synoptic stations are expected to report every six hours for global exchange and every three hours for regional exchange, however with higher frequency on bilateral and multilateral arrangements. The details of the observational programmes provided by all stations operated by WMO Members are given in the WMO Observing Systems Capability Analysis and Review Tool (OSCAR) and available on the WMO website at https://oscar.wmo.int/OSCAR/index.html#/.
3. The approved operational procedures and practices are given in the regularly updated Manual on the Global Observing System (WMO-No. 544), and the Manual on the WMO Integrated Global Observing System (WMO-No. 1160) available also on the WMO website at http://www.wmo.int/pages/prog/www/OSY/Manuals_GOS.html and http://www.wmo.int/pages/prog/www/wigos/documents/WIGOS-RM/1160_en.pdf, respectively.
4. Under the Global Observing System of the World Weather Watch Programme, WMO Members operating stations in the Arctic Monitoring and Assessment Programme (AMAP) area (essentially includes the terrestrial and marine areas north of the Arctic Circle (66°32N), and north of 62°N in Asia and 60°N in North America, modified to include the marine areas north of the Aleutian chain, Hudson Bay, and parts of the North Atlantic Ocean including the Labrador Sea), contribute to the implementation of the observational programme by operating 336 surface Regional Basic Synoptic and 156 Regional Basic Climatological stations. A detailed infomration is available through WMO OSCAR: https://oscar.wmo.int/OSCAR/index.html#/.