An important new paper on climate system heat content has appeared. It is Shin H.-J., I.-U. Chung, H.-J. Kim, J.-W. Kim (2006), Global energy cycle between land and ocean in the simulated 20th century climate systems, Geophys. Res. Lett., 33, L14702, doi:10.1029/2006GL025977.
The abstract of the paper reads,
“The global energy cycle between the land and the ocean has been studied with simulations of the 20th century performed with coupled ocean-atmosphere climate models. The energy cycle consists of the net energy fluxes at the top-of-the-atmosphere (TOA) and the surface, the atmospheric energy storage rates over the global land and ocean, and the atmospheric energy transport between the land and ocean. The energy cycle was investigated using a multi-model ensemble for its centennial mean, climatological annual variation and long-term trend. Some distinctive features of the cycle were revealed: (1) the ocean-to-land atmospheric energy transport plays a key role in partitioning the global net TOA flux between the ocean and land, (2) the annual variation of the global net TOA flux is primarily attributed by the ocean surface flux, and (3) it is ascertained that the planetary energy imbalance on the long-term period is induced by the ocean’s heat uptake. “
Excerpts from the Conclusion and Remarks state,
“…….the annual mean ocean-to-land energy transport can be largely explained by the global water cycle (characterized as the water vapor transport from the ocean to the land and its compensating run-off from the land to the ocean [Shin et al., 2002]). In conclusion, the authors believe that the global energy cycle between land and ocean is important to understand the climate system and climate change.”
“Through the analysis with the long-term time series of the TOA and the surface fluxes, the importance of the ocean’s role for the planetary energy imbalance was illuminated.”
This last conclusion further substantiated the conclusions in Pielke Sr., R.A., 2003: Heat storage within the Earth system. Bull. Amer. Meteor. Soc., 84, 331-335 that
“The earth’s heat budget observations, within the limits of their representativeness and accuracy, provide an observational constraint on the radiative forcing imposed in retrospective climate modeling.
A snapshot at any time documents the accumulated heat content and its change since the last assessment. Unlike temperature, at some specific level of the ocean, land, or the atmosphere, in which there is a time lag in its response to radiative forcing, there are no time lags associated with heat changes.
Since the surface temperature is a two-dimensional global field, while heat content involves volume integrals ……the utilization of surface temperature as a monitor of the earth system climate change is not particularly useful in evaluating the heat storage changes to the earth system. The heat storage changes, rather than surface temperatures, should be used to determine what fraction of the radiative fluxes at the top of the atmosphere are in radiative equilibrium….”.
The recognition of the importance of ocean heat content changes is a reason that the paper
Lyman J. M., J. K. Willis, G. C. Johnson (2006), Recent cooling of the upper ocean, Geophys. Res. Lett., 33, L18604, doi:10.1029/2006GL027033
should receive a lot of attention. This paper represents another challenge to the IPCC perspective on the use of global average surface air temperature trends as the primary global warming metric.
The new Shin et al paper is an excellent new contribution which provides further evidence as to why a change to the assessment of global average ocean heat content variability and trends is needed.