Development of a global gridded Argo data set with Barnes successive corrections

Abstract

A new 11 year (2004–2014) monthly 1° gridded Argo temperature and salinity data set with 49 vertical levels from the surface to 1950 m depth (named BOA-Argo) is generated for use in ocean research and modeling studies. The data set is produced based on refined Barnes successive corrections by adopting flexible response functions based on a series of error analyses to minimize errors induced by nonuniform spatial distribution of Argo observations. These response functions allow BOA-Argo to capture a greater portion of mesoscale and large-scale signals while compressing small-sale and high-frequency noise relative to the most recent version of the World Ocean Atlas (WOA). BOA-Argo data set is evaluated against other gridded data sets, such as WOA13, Roemmich-Argo, Jamestec-Argo, EN4-Argo, and IPRC-Argo in terms of climatology, independent observations, mixed-layer depth, and so on. Generally, BOA-Argo compares well with other Argo gridded data sets. The RMSEs and correlation coefficients of compared variables from BOA-Argo agree most with those from the Roemmich-Argo. In particular, more mesoscale features are retained in BOA-Argo than others as compared to satellite sea surface heights. These results indicate that the BOA-Argo data set is a useful and promising adding to the current Argo data sets. The proposed refined Barnes method is computationally simple and efficient, so that the BOA-Argo data set can be easily updated to keep pace with tremendous daily increases in the volume of Argo temperature and salinity data.