Figure 2: (a) Observation-based estimates of annual global mean upper (0 to 700m) ocean heat content in ZJ (1 ZJ = 1021 Joules) updated from (see legend): Levitus et al. (2012), Ishii and Kimoto (2009), Domingues et al. (2008), Palmer et al. (2007) and Smith and Murphy (2007). Uncertainties are shaded and plotted as published (at the one standard error level, except one standard deviation for Levitus, with no uncertainties provided for Smith). Estimates are shifted to align for 2006–2010, 5 years that are well measured by Argo, and then plotted relative to the resulting mean of all curves for 1971, the starting year for trend calculations.
(b) Observation-based estimates of annual 5-year running mean global mean mid-depth (700 to 2000 m) ocean heat content in ZJ (Levitus et al., 2012) and the deep (2000 to 6000 m) global ocean heat content trend from 1992 to 2005 (Purkey and Johnson, 2010), both with one standard error uncertainties shaded (see legend).
Reference: IPCC 5th Assessment Report, WG1 Ch3. Ocean Observations.