Remotely Sense Spatial and Temporal Dynamic of the Leeuwin Current using Time-series MODIS Data  

Authors / CoAuthors

Huang, Z.

Abstract

The Leeuwin Current has significant ecological impact on the coastal and marine ecosystem of south-western Australia. This study investigated the spatial and temporal dynamics of the Leeuwin Current using monthly MODIS SST dataset between July 2002 and December 2012. Topographic Position Index layers were derived from the SST data for the mapping of the spatial structure of the Leeuwin Current. The semi-automatic classification process involves segmentation, 'seeds' growing and manual editing. The mapping results enabled us to quantitatively examine the current's spatial and temporal dynamics in structure, strength, cross-shelf movement and chlorophyll a characteristic. It was found that the Leeuwin Current exhibits complex spatial structure, with a number of meanders, offshoots and eddies developed from the current core along its flowing path. The Leeuwin Current has a clear seasonal cycle. During austral winter, the current locates closer to the coast (near shelf break), becomes stronger in strength and has higher chlorophyll a concentrations. While, during austral summer, the current moves offshore, reduces its strength and chlorophyll a concentrations. The Leeuwin Current also has notable inter-annual variation due to ENSO events. In El Niño years the current is likely to reduce strength, move further inshore and increase its chlorophyll a concentrations. The opposite occurs during the La Niña years. In addition, this study also demonstrated that the Leeuwin Current has a significantly positive influence over the regional nutrient characteristics during the winter and autumn seasons. Apart from surface cooling and advection, the Leeuwin Current's sizable cross-shelf movement may be another contributing factor to the seasonal and inter-annual variations of its chlorophyll a concentrations.

Product Type

nonGeographicDataset

eCat Id

79140

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Keywords

• External PublicationArticle

( Theme )

• mapping

( Theme )

• remote sensing

( Theme )

• marine

( Theme )

• NERP

Australian and New Zealand Standard Research Classification (ANZSRC)

• Marine Geoscience

• Published_Internal

Publication Date

2014-01-01T00:00:00

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Australian Government Security ClassificationSystem    

Classification - unclassified

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Creative Commons Attribution 4.0 International Licence    

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notPlanned

Topic Category

oceans

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This paper was based on the results of NERP Marine Biodiversity Hub research (Theme 3 Project 1): Shelf and Canyon Ecosystem Processes.

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