eCite Digital Repository

An assessment of multiple westward propagating signals in sea level anomalies


Maharaj, AM and Holbrook, NJ and Cipollini, P, An assessment of multiple westward propagating signals in sea level anomalies, Journal of Geophysical Research - Oceans, 114, (C12016) pp. 1-14. ISSN 0148-0227 (2009) [Refereed Article]

Restricted - Request a copy

Copyright Statement

Copyright 2009 by the American Geophysical Union.

Official URL:

DOI: doi:10.1029/2008JC004799


The characteristics of multiple westward propagating signals in the satellite observed South Pacific sea level anomalies (SLA) between 10S and 50S are analyzed using the two-dimensional Radon transform (2D-RT). We test the hypothesis that these signals are most likely to be the signature of the first few baroclinic Rossby wave modes. This involves a comparison of the estimated phase speeds of the 2D-RT peaks against the first four baroclinic mode Rossby wave speeds predicted from the extended theory. The 2D-RT analysis typically identified up to three propagating signals in the SLA and very occasionally, a fourth. The first Radon transform (RT) peak phase speeds corresponded very well with first baroclinic mode Rossby wave phase speed estimates from linear theory between 15S and 25S and the extended theory phase speed estimates poleward of 25S. RT peak 2 speeds were less coherent but fell within the range of extended theory estimates of the first four baroclinic Rossby wave modes, consistent with large-scale Rossby wave dynamics. The relationship between peaks 3 and 4 and the extended theory higher-order baroclinic mode speed estimates varied markedly across the basin. Regional variability in the spectral characteristics of the peaks suggests that different dynamical regimes dominate north and south of 30S in the South Pacific basin. The presence of secondary peaks in the middle to high latitudes suggests that higher-order modes may play a role in these regions.

Item Details

Item Type:Refereed Article
Keywords:Rossby waves, sea level anomalies, radon transform
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical oceanography
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Oceanic processes (excl. in the Antarctic and Southern Ocean)
UTAS Author:Holbrook, NJ (Professor Neil Holbrook)
ID Code:57371
Year Published:2009
Web of Science® Times Cited:19
Deposited By:Geography and Environmental Studies
Deposited On:2009-07-12
Last Modified:2010-04-14
Downloads:1 View Download Statistics

Repository Staff Only: item control page