World Meteorological Organization

The GCOS Surface Network (GSN) is a baseline network comprising a subset of about 1000 stations chosen mainly to give a fairly uniform spatial coverage from places where there is a good length and quality of data record. A particular product of these stations, additional to their synoptic data, is a monthly CLIMAT message that, in principle, can include monthly averages, extremes and threshold exceedances for temperature, precipitation and sunshine duration (WMO, 2014a). Transmission, completeness and quality of CLIMAT data are monitored, and coding corrections made where possible, by Deutcher Wetter Dienst (DWD) and the Japan Meteorological Agency (JMA) in their capacities as GSN Monitoring Centres (GSNMCs). Production of monthly CLIMAT messages is also expected of the close to 3000 stations that comprise RBCN; increasing the number of RBCN stations that actually supply such messages has been one subject of recent attention. Another recent initiative has been to develop a message template for reporting daily values within the monthly message; steps are now being taken towards implementation of this additional reporting.analysis.