The value of using the ocean heat budget to diagnose the radiative imbalance at the top of the atmosphere was originally presented in the seminal paper
Ellis et al. 1978: The annual variation in the global heat balance of the Earth. J. Climate. 83, 1958-1962.
This was a motivation for the paper
Pielke Sr., R.A., 2003: Heat storage within the Earth system. Bull. Amer. Meteor. Soc., 84, 331-335.
In the Ellis et al paper on page 1961, the variation in the annual amplitude variation in the solar radiative forcing of 11.2 Watts per meter squared (due to the Earth’s elliptical orbit around the Sun) provides a perspective on global warming and cooling due to this “purely external driving mechanism”. While this heat imbalance sums to zero in an annual average, there clearly is global warming and cooling within each year. When all of the influences on the global heat budget are considered (see Figure 4), the variation across the year is on the order of 40 Watts per meter squared. This large variation in the value of global radiative imbalance within the year makes the accurate diagnosis of the multi-decadal trends in anthropogenic radiative forcing (the estimated 1.6 Watts per meter squared total net anthropogenic value of 1.6 Watts per meter squared) in Figure SPM-2 of the 2007 IPCC Statement for Policymakers a challenge.
This paper also confirms that dominate role of the oceans in the climate system response to the annual variation in solar insolation. They also express a particular interest in possible interannual variations from the average conditions reported in their paper. With the new ocean observing system (Argo), the plots of the estimated radiative imbalance should be prepared in near-real time on a monthly basis.