ENSO-driven energy budget perturbations in observations and CMIP models

Journal Article · Sat Mar 19 00:00:00 EDT 2016 · Climate Dynamics

DOI:https://doi.org/10.1007/s00382-016-3057-z· OSTI ID:1425660

Mayer, Michael ^[1]; Fasullo, John T. ^[2]; Trenberth, Kevin E. ^[2]; Haimberger, Leopold ^[1]

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1. Univ. of Vienna (Austria). Dept. of Meteorology and Geophysics
2. National Center for Atmospheric Research, Boulder, CO (United States)

Various observation-based datasets are employed to robustly quantify changes in ocean heat content (OHC), anomalous ocean–atmosphere energy exchanges and atmospheric energy transports during El Niño-Southern Oscillation (ENSO). These results are used as a benchmark to evaluate the energy pathways during ENSO as simulated by coupled climate model runs from the CMIP3 and CMIP5 archives. The models are able to qualitatively reproduce observed patterns of ENSO-related energy budget variability to some degree, but key aspects are seriously biased. Area-averaged tropical Pacific OHC variability associated with ENSO is greatly underestimated by all models because of strongly biased responses of net radiation at top-of-the-atmosphere to ENSO. The latter are related to biases of mean convective activity in the models and project on surface energy fluxes in the eastern Pacific Intertropical Convergence Zone region. Moreover, models underestimate horizontal and vertical OHC redistribution in association with the generally too weak Bjerknes feedback, leading to a modeled ENSO affecting a too shallow layer of the Pacific. Vertical links between SST and OHC variability are too weak even in models driven with observed winds, indicating shortcomings of the ocean models. Furthermore, modeled teleconnections as measured by tropical Atlantic OHC variability are too weak and the tropical zonal mean ENSO signal is strongly underestimated or even completely missing in most of the considered models. In conclusion, results suggest that attempts to infer insight about climate sensitivity from ENSO-related variability are likely to be hampered by biases in ENSO in CMIP simulations that do not bear a clear link to future changes.

• Research Organization: National Center for Atmospheric Research, Boulder, CO, USA
• Sponsoring Organization: USDOE; European Union (EU); National Science Foundation (NSF)
• Grant/Contract Number: SC0012711; 265229
• OSTI ID: 1425660
• Journal Information: Climate Dynamics, Vol. 47, Issue 12; ISSN 0930-7575
• Publisher: Springer-Verlag
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ENSO
Coupled atmosphere-ocean energy budget
Reanalysis
Climate models
CMIP