Sea surface height observations of the 34 degrees N 'waveguide' in the North Atlantic

We present a study of the energetic zonal band at 34 degreesN in the North Atlantic using a wavelet analysis of more than 8 years of TOPEX/POSEIDON al timeter data. It is already well-established in the literature that this zo nal 'waveguide' is dominated by large-scale propagating features. The wavel et analysis yields sea surface height variance at a range of periods and wa velengths, allowing us to observe and quantify evolution of the features in space and time. Signal variance west of the mid-Atlantic ridge at 34 degre esN is larger than to the east of the ridge: by a factor of (similar to)2 i n the period band 0.5-0.9 years, in which baroclinic Rossby waves and eddie s propagate. The period of the peak energy is reduced crossing the ridge fr om (similar to)1 year to (similar to)7-9 months, before rising again to the annual cycle on the other side. There is also evidence of energy peaks at periods of (similar to)2-4 years in the Gulf Stream region and east of the ridge.