The Heat Content of Earth's Climate System

The oceans are the dominant reservoir for the storage of heat in the climate system. Changes in the global climate that occur from a net imbalance between incoming and outgoing radiation at the top of Earth’s atmosphere, result in the accumulation of heat in the ocean.

Over the past 50 years Earth's oceans have accumulated over 90 percent of the excess heat from the radiative imbalance due to human caused greenhouse gases. Oceans provide a means of monitoring the cumulative impact of climate forcing over time.

Measuring the net radiative imbalance

The Center of Climate Sciences at NASA's Jet Propulsion Laboratory works to bring together measurements of the variability in the net radiative imbalance using NASA Terra and Aqua data products. The Center will also factor in new estimates of the ocean heat content to be developed as part of a proposed ROSES 2010 effort titled “Ocean Warming and the Earth's Energy Balance” (proposal number 10-PO10-0009).

These observations will provide a means of tracking the radiative imbalance over time and attributing it to specific physical mechanisms. The Center's primary goal is to analyze estimates of ocean heat content variability from the early 1990s to the present in conjunction with observations of the radiative balance over the past decade in order to provide insight into the mechanisms of global climate change.

Determining the cause of discrepancies

The Center also proposes additional analysis of ocean heat content and satellite radiation observations to determine the cause of the apparent discrepancy between existing estimates, specifically the slight decrease in warming rate during recent years that appears in the most recent ocean heat content estimates.

Numerous satellite data sources

In addition, further analysis of El Nino related signals in Earth’s energy balance will be explored for the events from 2000 to the present. This work will address the scientific thrust of physical oceanography at NASA that aims to understand the ocean’s role in climate variability by making extensive use of a variety of satellite observations, and by providing a platform for cross–cutting research. In so doing, a unique opportunity exists to address a critical gap in the understanding of Earth’s climate system by fostering collaboration between atmospheric and oceanic climate scientists with expertise in satellite observations of radiation balance and ocean heat content.