A high-resolution boundary current product from Gridded Observations of eXpendable BathyThermograph (XBT) transects

Abstract The Ship Of Opportunity Expendable BathyThermograph (SOOP-XBT) Network has been measuring upper ocean temperature aboard volunteer vessels over multiple decades in key locations of the global ocean. Through international collaboration, these data are systematically collected, quality-controlled and made available to the scientific and operational communities. The network’s strengths: its low cost, high spatial resolution, and long-term repeatability, have made it a key asset for advancing ocean state estimation and climate studies. Here, we introduce a synthesis of formatted XBT data from selected transects across the global ocean, and provide a high-quality gridded product of temperature and derived salinity and absolute geostrophic velocity across five major boundary currents: the Gulf Stream, Kuroshio, East Australian Current, Brazil Current and the Antarctic Circumpolar Current. The Gridded Observations of XBT transects (GOXBT) product offers a unique temporal coverage and spatial resolution, providing a critical resource for ocean model and reanalysis validation, and supporting future studies on the variability and dynamics of major ocean currents.