Modeling events of sea-surface variability using spectral nudging in an eddy permitting model of the northeast Pacific Ocean

Abstract

[ 1] Eddies are an important part of the current system that hugs the coasts of British Columbia and Alaska. The ability of "spectral nudging'' to improve the eddy statistics determined from model simulations of this current system is investigated. Spectral nudging differs from standard nudging in that only specified frequency and wave number bands of the simulated potential temperature and salinity fields are nudged toward the observed climatology. Therefore the simulated eddy field can develop and evolve with time while the model is prevented from drifting far from the observed climatology. The Parallel Ocean Program ( POP) is used to do the simulations, with 0.25 degrees horizontal resolution and 23 vertical levels. The simulated standard deviation and skewness fields for the sea surface height are compared with those estimated from ten years of TOPEX/ Poseidon altimetry observations. This comparison shows that spectral nudging allows the model to simulate the eddy statistics of the current system with significantly more accuracy than when the nudging is not used.