Cordero-Quiros, N., A. J. Miller, Y. Pan, L. Balitaan,
E. Curchitser and R. Dussin, 2022:
Physical-ecological response of the California Current System
to ENSO events in ROMS-NEMURO
Ocean Dynamics, 72, 21-36.
We analyze the bottom-up El Niņo/Southern Oscillation (ENSO) driven physical-biological
response of the California Current System (CCS) in a high-resolution, "eddy-scale"
ocean model with multiple classes of phytoplankton and zooplankton forced with observed
winds over the time period 1959-2007. The response of the sea surface temperature anomalies
over the CCS is asymmetrical, with La Niņa events being more consistently cold than El Niņo
events are consistently warm, which is in agreement with previous studies. The biogeochemical
and ecological response is represented by ENSO-composite anomalies, lag-correlations with an
ENSO index, and histograms for ENSO years. The results show trophic level interactions during
El Niņo and La Niņa events in which the larger components (diatoms, euphausiids, and
copepods) are suppressed in the coastal upwelling zones during El Niņo, while the smaller
components (flagellates and ciliates) are enhanced. In addition, standing eddies of the CCS
modulate the latitudinal structure of the ecological response to ENSO. The results point towards
future research to understand how bottom-up changes may lead to variability of patterns in
ecological response, including fish populations and top predators.