An internally consistent data product for the world ocean: the Global Ocean Data Analysis Project, version 2 (GLODAPv2)

For version 2 of the Global Ocean Data Analysis Project (GLODAPv2) we collated data from 724 scientific cruises covering the global ocean: data assembled in the previous efforts GLODAPv1.1 (Global Ocean Data Analysis Project version 1.1) in 2004, CARINA (CARbon IN the Atlantic) in 2009/10, and PACIFICA (PACIFic ocean Interior CArbon) in 2013, and an additional 168 cruises. Twelve core parameters (salinity, oxygen, macronutrients, seawater CO2 chemistry parameters and halogenated transient tracers) have been subjected to extensive quality control including systematic evaluation of biases between cruises. The data are available in two formats: (i) as submitted but updated to WOCE exchange format whenever required, and (ii) as a merged and calibrated data product. In the latter, adjustments have been applied to remove significant biases, respecting occurrences of any known or likely time trends. Adjustments determined by previous efforts have been re-evaluated. Hence, GLODAPv2 is not a simple merge of previous collections and some new data, but represents a unique, internally consistent data product. The original data and their documentation and doi codes are available at the Carbon Dioxide Information Analysis Center (http://cdiac.ornl.gov/oceans/GLODAPv2/). This site also provides access to the calibrated data product, which is provided as a single global file or 4 regional ones: the Arctic, Atlantic, Indian, and Pacific Oceans, under the doi:10.3334/CDIAC/OTG.NDP093_GLODAPv2. The product files also include significant ancillary and approximated data. The latter were obtained either by interpolation of, or by calculation from, measured data. This paper documents the GLODAPv2 history, methods, and products, including a broad overview of the secondary quality control results. The magnitude of and reasoning behind the adjustments are available on a per cruise and parameter basis in an online Adjustment Table.