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. Mandaoty paramters measured by a GSN station are temperature and precipitation.
Near Real Time data are available at the GSN Monitoring Centre (GSNMC). Historical GSN data are available online from the NOAA NCEI. The following statistics are an annual summary of the monthly CLIMAT messages in the GCOS Climate Archive (National Climate Environmental Information, NCEI, US). According to the GCOS requirements, a fully compliant GSN/RBCN shall have 12 CLIMAT reports. The values represent the 2018 percentage (Oct 2017 to Sept 2018) of stations that are compliant and those that are partially or non-compliant. In brackets are the statistics for 2017, 2016, 2015, 2014, 2013, 2012 and 2011 respectively.
| Region | No. | 12 Monthly CLIMAT | 6 - 11 Monthly CLIMAT | 1 - 5 Monthly CLIMAT | 0 Monthly CLIMAT |
| RA-I | 155 | 37% (31, 40, 29, 29, 32, 28, 23) | 23% (34, 25, 31, 33, 33, 36, 39) | 5% (3, 9, 15, 10, 10, 11, 14) | 35% (32, 26, 25, 28, 25, 25, 24) |
| RA-II | 258 | 76% ( 79, 83, 78, 71, 73, 73, 75) | 17% (15, 10, 14, 21, 19, 19, 19) | 1% (0, 2, 2, 3, 2, 2, 1) | 6% (6, 5, 6, 5, 6, 6, 5) |
| RA-III | 101 | 61% (63, 65, 61, 76, 89, 84, 69) | 16% (15, 29, 35, 20, 6, 13, 28) | 4% (6, 0, 0, 1, 0, 0, 0) | 19% (16, 6, 4, 3, 5, 3, 3) |
| RA-IV | 178 | 86% (86, 90, 88, 88, 88, 81, 80) | 11% (12, 7, 9, 10, 11, 17, 18) | 1% (1, 2, 2, 1, 1, 1, 1) | 2% (1, 1, 1, 1, 0, 1, 1) |
| RA-V | 151 | 64% (61, 67, 66, 70, 63, 58, 52) | 18% (21, 15, 16, 17, 16, 23, 34) | 3% (3, 3, 4, 1, 7, 7, 1) | 15% (15, 15, 14, 13, 14, 12, 11) |
| RA-VI | 138 | 77% (82, 84, 77, 80, 82, 78, 81) | 14% (8, 7, 14, 9, 12, 17, 15) | 1% (2, 2, 3, 5, 2, 1, 0) | 8% (8, 7, 6, 6, 4, 4, 4) |
| ANTON | 42 | 81% (83, 81, 77, 79, 60, 45, 50) | 17% (12, 17, 19, 19, 36, 43, 33) | 2% (5, 2, 2, 2, 2, 5, 12) | 0% (0, 0, 2, 0, 2, 7, 5) |
The detailed current state of the GSN and its performance indicators are provided by the Global Observing Systems Information Center.
A report on the network perfomance in 2018 is available here.
