Expendable bathythermograph (XBT) measures temperature down to the depth of about 800 m from a moving ship. Since the late 1960s XBTs contributed the majority of the subsurface temperature measurements in the ocean. However the XBT sample depth is not measured but calculated from the estimated fall-rate. The uncertainties in the fall-rate and the malfunctioning of the acquisition system cause XBT temperatures to be biased.
Biases in the XBT data has been documented in the literature since 1970s, but it was not until recently that their integrated effect on the global heat content calculations has been estimated. The XBT temperature bias was shown to be comparable in magnitude with the typical decadal-scale temperature variability , so that neglecting this bias can seriously distort our estimates of global ocean climate change. Using original XBT data from the World ocean database WOD09 (Boyer et al., 2009) we provide a data product which includes depth- and temperature-corrected XBT profiles. The correction method is based on the recent study by Gouretski and Reseghetti (2010).
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