Development of an Integrated Global Land Surface Dataset from 1901 to 2018

We developed an integrated global land surface dataset (IGLD) at the National Meteorological Information Center of China Meteorological Administration. The IGLD consists of hourly data for 75 variables from five data sources. It contains not only the most widely used variables (e.g., pressure, temperature, dew-point temperature, and precipitation), but also visibility, cloud cover, snow depth, and so on. A hierarchy of data sources was created to identify duplicate records. The records located higher in the hierarchy were adopted preferentially in the IGLD. A comprehen-sive quality control procedure including extreme value test, internal consistency check, and spatiotemporal consistency check, was applied to the IGLD. The IGLD consists of land surface observations at more than 20,000 global sites from 1901 to 2018, of which about 17,000 stations are currently active. The number of global observatories generally increased over time, except for the 1960s to 1970s. It increased from about 2300 in 1951 to 17,000 in 2018. The observations over America, Europe, and eastern Asia always showed a high temporal integrity and dense spatial coverage, whereas measurements were sparser in South America, Africa, Russia, and the Mediterranean regions. In general, the standard and intermediate standard times for observation suggested by the World Meteorological Organization (WMO) were followed globally, except in Australia, where there were few data measured on the WMO schedule. The IGLD has been used in the China’s first generation global atmospheric reanalysis product (CRA) and the global daily precipitation dataset.