Evolution of Ocean Heat Content Related to ENSO

Journal Article · 23 May 2019 · Journal of Climate

DOI: https://doi.org/10.1175/jcli-d-18-0607.1 · OSTI ID:1515583

Cheng, Lijing  ^[1]; Trenberth, Kevin E. ^[2]; Fasullo, John T. ^[2]; Mayer, Michael ^[3]; Balmaseda, Magdalena ^[4]; Zhu, Jiang ^[1]

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1. Chinese Academy of Sciences (CAS), Beijing (China)
2. National Center for Atmospheric Research (NCAR), Boulder, CO (United States)
3. European Centre for Medium-Range Weather Forecasts, Reading (United Kingdom); Univ. of Vienna (Austria)
4. European Centre for Medium-Range Weather Forecasts, Reading (United Kingdom)

As the strongest interannual perturbation to the climate system, El Niño–Southern Oscillation (ENSO) dominates the year-to-year variability of the ocean energy budget. Here we combine ocean observations, reanalyses, and surface flux data with Earth system model simulations to obtain estimates of the different terms affecting the redistribution of energy in the Earth system during ENSO events, including exchanges between ocean and atmosphere and among different ocean basins, and lateral and vertical rearrangements. This comprehensive inventory allows better understanding of the regional and global evolution of ocean heat related to ENSO and provides observational metrics to benchmark performance of climate models. Results confirm that there is a strong negative ocean heat content tendency (OHCT) in the tropical Pacific Ocean during El Niño, mainly through enhanced air–sea heat fluxes Q into the atmosphere driven by high sea surface temperatures. In addition to this diabatic component, there is an adiabatic redistribution of heat both laterally and vertically (0–100 and 100–300 m) in the tropical Pacific and Indian oceans that dominates the local OHCT. Heat is also transported and discharged from 20°S–5°N into off-equatorial regions within 5°–20°N during and after El Niño. OHCT and Q changes outside the tropical Pacific Ocean indicate the ENSO-driven atmospheric teleconnections and changes of ocean heat transport (i.e., Indonesian Throughflow). The tropical Atlantic and Indian Oceans warm during El Niño, partly offsetting the tropical Pacific cooling for the tropical oceans as a whole. While there are distinct regional OHCT changes, many compensate each other, resulting in a weak but robust net global ocean cooling during and after El Niño.

• Research Organization: University Corporation for Atmospheric Research (UCAR), Boulder, CO (United States)
• Sponsoring Organization: USDOE Office of Science (SC); National Key Research and Development Program of China; National Science Foundation (NSF); USDOE
• Grant/Contract Number: SC0012711; 2017YFA0603202; 2016YFC1401705; AGS-1243125
• OSTI ID: 1515583
• Alternate ID(s): OSTI ID: 1611937
• Journal Information: Journal of Climate, Vol. 32, Issue 12; ISSN 0894-8755
• Publisher: American Meteorological SocietyCopyright Statement
• Country of Publication: United States
• Language: English