Methodology Data Collection Figure 1 of this indicator reports on the amount of heat stored in the ocean from sea level to a depth of 700 meters, which accounts for approximately 17.5 percent of the total global ocean volume (calculation from Catia Domingues, CSIRO). Figure 2 reports on the amount of heat stored to a depth of 2,000 meters, which accounts for approximately 48.5 percent of the total global ocean volume (calculation from Catia Domingues, CSIRO). Each of the studies
used to develop this indicator uses several ocean temperature profile data sets to calculate an ocean heat content trend line.
Several different devices are used to sample temperature profiles in the ocean. Primary methods used to collect data for this indicator include XBT; mechanical bathythermographs (MBT); Argo profiling floats; reversing thermometers; and conductivity, temperature, and depth sensors (CTD). These instruments produce temperature profile measurements of the ocean water column by recording data on temperature and depth. The exact methods used to record temperature and depth vary. For instance, XBTs use a fall rate equation to determine depth, whereas other devices measure depth directly.