Cordero-Quirós, N., A. J. Miller, A. C. Subramanian and J. Y. Luo, 2019:

A composite physical-biological ENSO in the California Current System in CESM1-POP2-BEC


Ocean Modelling, sub judice.

Abstract. El Niño Southern Oscillation (ENSO) is recognized as one of the potentially predictable drivers of California Current System (CCS) variability. In this study, we analyze a 67-year coarse-resolution (~1deg) simulation of CESM-POP-BEC forced by NCEP/NCAR reanalysis winds to develop a model composite of the physical- biological response of the CCS during ENSO events. The results are also compared with available observations. The composite anomalies for sea surface temperature (SST), pycnocline depth, vertically averaged chlorophyll, zooplankton, nitrate, and oxygen exhibit many of the expected large-scale relationships between physics and the ecosystem, including reduced production during El Niño, and vice versa. However, the model response is generally weaker than observed and includes a typical 1-2 month delay compared to observations. We also highlight an interesting asymmetry in the model CCS response, where composite La Niña events are stronger and more significant than El Niño events, which is also found in observations. These physical-biological composites provide a comprehensive view of the potentially predictable impact of ENSO on the CCS, and set the stage for future work with high-resolution models and more complete observational datasets.

Preprint (pdf)