An algorithm for classifying unknown expendable bathythermograph (XBT) instruments based on existing meta data

AbstractTime-varying biases in expendable bathythermograph(XBT) instruments have emerged as a key uncertainty in estimates of historical ocean heat contentvariability and change. One of the challenges for development of XBT bias corrections is the lack of meta data in ocean profile databases. Approximately 50 % of XBT profiles in the World Ocean database (WOD) have no information about manufacturer or probe type. Building on previous research efforts, we present a deterministic algorithmfor assigning missing XBT manufacturer and probe type for individual temperature profiles based on: (i) the reporting country; (ii) maximum reported depth; and (iii) the record date. The criteria used are based on bulk analysis of known XBT profiles in WOD for the period 1966-2015. A basic skillassessment demonstrates a 77% success rate at correctly assigning manufacturer and probe type for profiles where this information is available. The skill rate is lowest during the early 1990s, which is also a period when meta da...