This paper "Earth's energy imbalance: Confirmation and implications. Science, 308, 1431-1435 Hansen et al" pdf available http://pubs.giss.nasa.gov/abstracts/2005/Hansen_etal_1.html seems to have been very influential in research on climate change. The basic argument is that very little of the earth's heat is stored in the atmosphere and that the heat stored in the first 2.5 meters of the ocean is equivalent to the whole atmosphere. Therefore ocean heat storage is a more reliable tool to measure the radiative imbalances in our climate system than surface temperature changes. I've noticed that even researchers at the far end of climate debate from Hansen are starting to use the ocean heat storage metric in their papers. Part of this is probably driven by deployment of the Argo float system that has given us unprecedented capacity to measure changes in ocean temperatures down to 2000 meters. http://www.argo.ucsd.edu/ . There are currently 3325 active Argo floats providing real time information about ocean conditions.