Cordero-Quirós, N., A. J. Miller, A. C. Subramanian and J. Y. Luo, 2018:

A composite physical-biological ENSO in the California Current System


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. Changes in the physical and biogeochemical state of the CCS arise from the local and remote sources of variability imprinted by the ENSO. Yet the dynamical response of the ocean is less understood mainly due to sparse observations. Long-run simulations represent an adequate tool to address the ENSO-related variability of the CCS, and a good complement to observations. In this study we analyze a 67-year simulation from NCAR to composite the physical-biological response of the CCS during ENSO events. The results show the evolution of 13 El Niño and 13 La Niña anomalies for sea surface temperature (SST), pycnocline depth, vertically integrated chlorophyll, and zooplankton over the whole CCS. In addition, we show the composite variability of nitrate and oxygen compared to neutral years along the U.S. West Coast. We find that the model has a 3-month lag with respect to the observations but captures the observed latitudinal dependence of the upwelling timing and the chlorophyll summer blooms. Our results also show that the modeled and observed distribution of sea surface temperature anomalies (SSTa) over CCS is skewed towards warm temperatures and that La Niña events are stronger and more significant.

Preprint (pdf)