National Oceanic and
Atmospheric Administration
United States Department of Commerce


FY 2017

As El Niño builds, Pacific Warm Pool expands, ocean gains more heat

Johnson, G.C., and A.N. Birnbaum

Geophys. Res. Lett., 44(1), 438–445, doi: 10.1002/2016GL071767 (2017)

El Niño–Southern Oscillation (ENSO) effects substantial redistributions of ocean temperature, both horizontal and vertical, on interannual time scales, especially in the Pacific Ocean. Analyses of monthly Argo-based ocean temperature maps illustrate large-scale ocean heat content redistributions with ENSO. They quantify a globally averaged sea surface temperature warming of ~0.1°C with a 1°C increase of the Niño3.4 index (a moderate El Niño), a substantial perturbation to the 0.13°C decade−1 trend in sea surface temperature. Monthly satellite-based estimates of Earth's energy imbalance suggest that a 1°C increase of the Niño3.4 index corresponds to an increase of ~3.4 ZJ in Earth's energy storage, more gently modulating the longer-term ~114 ZJ decade−1 trend. Yearly global ocean heat content estimates based on ocean temperature data, with their reduced uncertainties compared to monthly maps, reveal interannual variations in Earth's energy storage that correspond well with satellite-based estimates.

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