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Global Historical Climatology Network

NOAA's National Climatic Data Center (NCDC) has developed and maintained the Global Historical Climatology Network-Monthly (GHCN-M) data set since 1992 (Vose et al. 1992). The GHCN-M data set was created with the intention of having a single repository of climate data for stations across the globe. In 1997, a second version (GHCN-M v2) of the data set was developed and released with improvements such as quality control and removal of inhomogeneities in the data record (non-climatic influences that could produce a false trend) and an increased number of stations and length of the data record (Peterson and Vose, 1997).

The GHCN-M v2 has been the official dataset since its release, and has been widely used in several international climate assessments, such as the Intergovernmental Panel on Climate Change, as well as our monthly State of the Climate reports and in the yearly State of the Climate published in the Bulletin of the American Meteorological Society.

NCDC scientists continued to improve the data set, resulting in a version 3 of GHCN-M. The primary advances in GHCN-M v3, versus GHCN-M v2, are further improvements to quality control processes, more advanced techniques for removing data inhomogeneities, and improved station coverage. For more information, please visit the GHCN-Monthly website.

On May 2, 2011, NCDC transitioned to GHCN-M v3 as the official land component of its global temperature monitoring efforts. GHCN-M v2 will continue to be updated through May 30, 2011, but no support for this version of the dataset will be provided.