Improved estimates of ocean heat content from 1960-2015
Abstract
Earth's energy imbalance (EEI) drives the ongoing global warming and can best be assessed across the historical record by ocean heat content (OHC) changes. An accurate assessment of OHC is a challenge mainly due to insufficient and irregular data coverage. Here we provide updated OHC estimates since 1960 with the goal of minimizing associated sampling error. A subsample test, in which subsets of data in the data-rich Argo era are co-located with historical ocean observation locations, is performed to quantify this error. Results imply that OHC variations on decadal and multi-decadal scales can reliably be represented by our advanced mapping method (i.e. ratio of signal to error is 3-25). The inferred integrated EEI based on the updated OHC is greater than reported in previous assessments, but is consistent with a reconstruction of the radiative imbalance at the top of atmosphere since 1985. Besides, OHC changes in six major ocean basins can also be reliably reconstructed on decadal-scales (ratio of signal to error is 2-20). All examined ocean basins experienced significant warming since 1998, although the heat was mainly stored in the Southern Ocean, Tropical Pacific and Tropical Atlantic during 1960-1998. A new look at OHC and EEI changes over time has provided greater confidence than previously possible. Changes in OHC were small prior to about 1980, but with fairly steady increases since then and increasingly involving deeper layers of the ocean after 1990. These datasets provide a valuable resource for further studies.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMGC34B..03C
- Keywords:
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- 3339 Ocean/atmosphere interactions;
- ATMOSPHERIC PROCESSESDE: 3360 Remote sensing;
- ATMOSPHERIC PROCESSESDE: 1620 Climate dynamics;
- GLOBAL CHANGEDE: 1635 Oceans;
- GLOBAL CHANGE