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Please use this identifier to cite or link to this item: http://hdl.handle.net/10204/6010

Title: Agulhas Current variability determined from space: a multi-sensor approach
Authors: Rouault, M
Keywords: Agulhas Current
Sea Surface Temperature
SST
Satellite remote sensing
Advanced Synthetic Aperture Radar
ASAR
Issue Date: Nov-2011
Citation: Rouault, M. 2011. Agulhas Current variability determined from space: a multi-sensor approach. University of Cape Town.
Series/Report no.: Workflow;8426
Abstract: Satellite remote sensing datasets including more than 6 years of high frequency Sea Surface Temperature (SST) imagery as well as surface current observations derived from 18 years of merged-altimetry and over 2 years of Advanced Synthetic Aperture Radar (ASAR) observations are combined to study the variability of the Agulhas Current. The newly available rangedirected surface currents velocities from ASAR, which rely on the careful analysis of the measured Doppler shift, show strong promise for monitoring the meso to sub-mesoscale features of the surface circulation. While the accuracy of ASAR surface current velocities suffers from occasional bias due to our current inability to systematically account for the wind-induced contribution to the Doppler shift signal, the ASAR surface current velocities are able to consistently highlight regions of strong current and shear. The synaptic nature and relatively high resolution of ASAR acquisitions make the ASAR derived current velocities a good complement to altimetry for the study of sub-mesoscale processes and western boundary current dynamics. Time-averaged range-directed surface currents derived from ASAR provide an improved map of the mean Agulhas Current flow, clearly showing the location of the Agulhas Current core over the 1000 m isobath and identifying the region at the shelf edge of the north-eastern Agulhas Bank as one of the most variable within the Agulhas Current. To determine the variability of the Agulhas Current, an algorithm to track the position of the current is developed and applied to the longer merged-altimetry and SST records.
Description: A thesis presented for the Degree of Doctor of Philosophy, Department of Oceanography, University of Cape Town.
URI: http://hdl.handle.net/10204/6010
Appears in Collections:Climate change
Earth observation
Coastal and marine systems
Ecosystems processes & dynamics
General science, engineering & technology

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