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Abstract

Previous literature has suggested that multiple
peaks in sea level anomalies (SLA) detected by twodimensional Fourier Transform (2D-FT) analysis are
spectral components of multiple propagating signals,
which may correspond to different baroclinic Rossby
wave modes. We test this hypothesis in the South Pacific
Ocean by applying a 2D-FT analysis to the long Rossby
wave signal determined from filtered TOPEX/Poseidon
and European Remote Sensing-1/2 satellite altimeter
derived SLA. The first four baroclinic mode dispersion
curves for the classical linear wave theory and the
Killworth and Blundell extended theory are used to
determine the spectral signature and energy contributions
of each mode. South of 17°S, the first two extended theory
modes explain up to 60% more of the variance in the
observed power spectral energy than their classical linear
theory counterparts. We find that Rossby wave modes 2–3
contribute to the total Rossby wave energy in the SLA data.
The second mode contributes significantly over most of the
basin. The third mode is also evident in some localized
regions of the South Pacific but may be ignored at the large
scale. Examination of a selection of case study sites
suggests that bathymetric effects may dominate at longer
wavelengths or permit higher order mode solutions, but
mean flow tends to be the more influential factor in the
extended theory. We discuss the regional variations in
frequency and wave number characteristics of the extended
theory modes across the South Pacific basin.

Item Type:	Article
Authors/Creators:	Maharaj, AM and Cipollini, P and Holbrook, NJ and Killworth, PD and Blundell, JR
Keywords:	Extended theory . Classical linear theory . South Pacific Ocean . Rossby waves . Baroclinic modes . Fourier transform
Journal or Publication Title:	Ocean Dynamics
ISSN:	1616-7228
DOI / ID Number:	10.1007/s10236-006-0099-5
Additional Information:	The original publication is available at www.springerlink.com
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