The Global Ocean Data Analysis Project (GLODAP) is a synthesis activity for ocean surface to bottom biogeochemical data collected through chemical analysis of water samples. Data for 12 core variables (salinity, oxygen, phosphate, nitrate, silicate, dissolved inorganic carbon, total alkalinity, pH, CFC-11, CFC-12, CFC-113 and CCl4) are subjected to primary and secondary quality control to identify outliers and correct for measurement biases. GLODAP is publicly available, discoverable, and citable. GLODAP enables quantification of the ocean carbon sink, ocean acidification and evaluation of ocean biogeochemical models. GLODAP was first published in 2004. The second version, GLODAPv2, was released in 2016. This forms the basis for regular updates, containing new data sets as well as updates of older ones. The first such regular update was GLODAPv2.2019. GLODAPv2.2021 adds data from 43 cruises to the previous release and extends coverage in time until 2020. GLODAPv2.2021 contains data from more than 1.3 million water samples collected on 989 cruises. An accompanying manuscript has been submitted for consideration for publication in Earth System Science Data.
