Title: ENSO-driven energy budget perturbations in observations and CMIP models

Abstract

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 zonalmore » 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.« less

Authors:

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

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+ Show Author Affiliations

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

Publication Date:

Sat Mar 19 00:00:00 EDT 2016

Research Org.:

National Center for Atmospheric Research, Boulder, CO, USA

Sponsoring Org.:

USDOE; European Union (EU); National Science Foundation (NSF)

OSTI Identifier:

1425660

Grant/Contract Number:  

SC0012711; 265229

Resource Type:

Accepted Manuscript

Journal Name:

Climate Dynamics

Additional Journal Information:

Journal Volume: 47; Journal Issue: 12; Journal ID: ISSN 0930-7575

Publisher:

Springer-Verlag

Country of Publication:

United States

Language:

English

Subject:

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