System of quasi-zonal jets off California revealed from satellite altimetry

Abstract

A discrete wavelet transform was applied to satellite altimetry data for the period 1992-2007 off California to decompose the SSH signal into inter-annual, annual, semiannual and shorter period components. For the lowest frequency (inter-annual) component, a system of alternating quasi-zonal jets was detected. The jet system was delineated by a north-south series of quasi-zonal bands of co-rotating eddies; that is, the eddies were embedded in a shearing zonal flow. The direction of eddy rotation alternated between adjacent bands. The temporal behavior of the jet system showed the existence of quasi-stationary states and transitions between them. Observed non-linear effects of the evolution of the jets included southward drift at about 0.2 cm sec-1, deviations of the jets from the zonal direction, and re-forming of the jet system through decay and merging of eddy chains. Copyright 2009 by the American Geophysical Union.