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Publication Date
1 May 2023

ENSO-Induced Teleconnection: Process-Oriented Diagnostics to Assess Rossby Wave Sources and Ambient Flow Properties in Climate Models

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We examine the response of the north Pacific wintertime flow during El Nino in AMIP experiments using process-oriented diagnostics. The analysis focuses on applying metrics of the Rossby Wave Source (RWS) and mid-latitude jet dynamics to determine their role in establishing the anomalous Pacific North America (PNA) pattern. The PNA is crucial for communicating the response to ENSO over North America. The metrics correctly identify the PNA biases in different models and their general improvement between the AMIP5 and AMIP6 assessments.


The accuracy of the North Pacific circulation anomalies during El Nino can be determined from a simple set of flow diagnostics. The analysis will aid in the climate model development process. These Process Oriented Diagnostics (PODs) form an integral component of PODs available as part of the Model Diagnostics Task Force (MDTF). This capability can be provided as an interoperable component under the Coordinated Model Evaluations Capabilities (CMEC).


Climate model fidelity in representing ENSO-induced teleconnections remains a challenge, requiring clear evaluation metrics that are consistently applied. Here the response is assessed with process-oriented diagnostics that examine a chain of processes, from equatorial Pacific precipitation to the midlatitude circulation pattern over the Pacific–North American regions. The analysis identifies two metrics: spatially coherent Rossby Wave generation in the subtropical North Pacific, and a Rossby wave restoring force in western-central North Pacific. By applying these metrics to AMIP5 and AMIP6 models, more recent improvements in the El Nino response are clearly identified. Repeating this analysis frequently during the model development process keeps a regular check on the skill in the response to anomalous El Nino convection, in conjunction with changing ambient flow dependencies.

Point of Contact
Richard Neale
National Center for Atmospheric Research (NCAR)
Funding Program Area(s)