Role of ocean biology-induced climate feedback in the modulation of El Niño-Southern Oscillation

Abstract

El Niño-Southern Oscillation (ENSO) properties can be modulated by many factors; most previous studies have focused on physical aspects of the climate system in the tropical Pacific. Ocean biology-induced feedback (OBF) onto physics and bio-climate coupling have been the subject of much recent interest, revealing striking model dependence and even conflicting results. Current satellite data are able to resolve the space-time structure of oceanic signals both in biology and physics, providing an opportunity for quantifying their relationships. Here we use the biological signature from satellite ocean color data to/estimate interannual variability of the attenuation depth of solar radiation (Hp), a field linking ocean biology and physics. We then apply a singular value decomposition (SVD) analysis to interannual Hp and sea surface temperature (SST) anomaly fields to derive an empirical H p model which is incorporated in a hybrid coupled ocean-atmosphere model of the tropical Pacific to represent the OBF. It is shown that the OBF can have significant effects on ENSO behaviors, including its amplitude, oscillation periods and seasonal phase locking. Copyright 2009 by the American Geophysical Union.