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Variability and trends in the directional wave climate of the Southern Hemisphere

Citation

Hemer, MA and Church, JA and Hunter, JR, Variability and trends in the directional wave climate of the Southern Hemisphere, International Journal of Climatology , 30, (4) pp. 475-491. ISSN 1097-0088 (2010) [Refereed Article]

DOI: doi:10.1002/joc.1900

Abstract

The effect of interannual climate variability and change on the historic, directional wave climate of the Southern Hemisphere is presented. Owing to a lack of in situ wave observations, wave climate in the Southern Hemisphere is determined from satellite altimetry and global ocean wave models. Altimeter data span the period 1985 to present, with the exception of a 2-year gap in 19891991. Interannual variability and trends in the significant wave height are determined from the satellite altimeter record (1991 to present), and the dominant modes of variability are identified using an empirical orthogonal function (EOF) analysis. Significant wave heights in the Southern Ocean are observed to show a strong positive correlation with the Southern Annular Mode (SAM), particularly during Austral autumn and winter months. Correlation between altimeter derived significant wave heights and the Southern Oscillation Index is observed in the Pacific basin, which is consistent with several previous studies. Variability and trends of the directional wave climate are determined using the ERA-40 Waves Re-analysis for the period 19802001. Significant wave height, mean wave period and mean wave direction data are used to describe the climate of the wave energy flux vector. An EOF analysis of the wave energy flux vector is carried out to determine the dominant modes of variability of the directional seasonal wave energy flux climate. The dominant mode of variability during autumn and winter months is strongly correlated to the SAM. There is an anti-clockwise rotation of wave direction with the southward intensification of the Southern Ocean storm belt associated with the SAM. Clockwise rotation of flux vectors is observed in the Western Pacific Ocean during El-Nino events. Directional variability of the wave energy flux in the Western Pacific Ocean has previously been shown to be of importance to sand transport along the south-eastern Australian margin, and the New Zealand region. The directional variability of the wave energy flux of the Southern Ocean associated with the SAM is expected to be of importance to the wave-driven currents responsible for the transport of sand along coastal margins in the Southern Hemisphere, in particular those on the Southern and Western coastal margins of the Australian continent.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical Oceanography
Objective Division:Environment
Objective Group:Physical and Chemical Conditions of Water
Objective Field:Physical and Chemical Conditions of Water in Marine Environments
Author:Church, JA (Dr John Church)
Author:Hunter, JR (Dr John Hunter)
ID Code:70460
Year Published:2010
Web of Science® Times Cited:88
Deposited By:Research Division
Deposited On:2011-06-22
Last Modified:2015-02-03
Downloads:0

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