XBT Products - Global Ocean Heat Content
XBT data, combined with Argo temperature data, and satellite observations, are used by scientists to compute the time-series of the Global Ocean Heat content.
Figure - Global Ocean Heat Content between 0-700 meters.
Further details about the computation of the Global Ocean Heat Content using XBT data combined with, Argo profiles, and satellite measurements can be found here
Levitus, S., Antonov, J. I., Boyer, T. P., Baranova, O. K., Garcia, H. E., Locarnini, R. A., ... & Zweng, M. M. (2012). World ocean heat content and thermosteric sea level change (0–2000 m), 1955–2010. Geophysical Research Letters, 39(10). [pdf]