The Global Historical Climatology Network hourly (GHCNh) dataset

The Global Historical Climatology Network hourly (GHCNh) is NCEI’s next generation hourly dataset composed primarily of instantaneous weather station observations from fixed land stations worldwide. GHCNh has been developed as part of a collaboration with the European Union’s Copernicus Climate Change Service (C3S) and with key participation by the U.S. Air Force. On the C3S side, NCEI has partnered Maynooth University (The National University of Ireland) to collect and make historical land and marine surface weather data more easily accessible worldwide. At NCEI, GHCNh was developed to be vertically aligned with its GHCN daily counterpart (GHCNd). This means that the same identifiers are used for stations common to the daily and hourly datasets and these identifiers are managed and searchable in NCEI’s Historical Observing Metadata Repository (HOMR) database and via NCEI’s Data Access applications.

GHCNh is officially replacing the Integrated Surface Dataset (ISD), which has been provided since the early 2000s. It incorporates the same set of data sources as ISD, plus more than 100 additional data sources. Some of these new sources provide observations for only a small number of stations, whereas others provided by larger-scale meteorological observation networks provide data for hundreds or even thousands of stations. With these additional sources, GHCNh covers a longer time period than ISD with some records extending back into the 18th Century. For stations in the USA, GHCNh provides data keyed under the Climate Data Modernization Program (CDMP) and thus extends the record length (compared to ISD) for many U.S. stations. The set of meteorological parameters provided includes wind speed and direction and wind gust; temperature; dew point and/or wet bulb temperature; relative humidity; cloud coverage data; sea level and station level atmospheric pressure; altimeter setting; present weather; visibility; and snow depth. Hourly and sub-hourly precipitation totals from several observing networks are also provided in support of the National Weather Service’s rainfall intensity-duration-frequency calculations for Atlas 15.

In this talk, a description of the data sources and coverage of GHCNh will be discussed along with plans for its continued development. Two datasets derived from GHCNh–Local Climatological Data and Synoptic Summary of the Day–will also be discussed.