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East Australian Current (the EAC)

East Australian Current (the EAC). Where is it?. EAC Properties. Warm, deep, fast, nutrient poor water 100 km wide by 500km deep 30 million m 3 /s transport! Well known for eddy formation (can be 200km across!). Physical Description.

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East Australian Current (the EAC)

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  1. East Australian Current (the EAC)

  2. Where is it?

  3. EAC Properties • Warm, deep, fast, nutrient poor water • 100 km wide by 500km deep • 30 million m3/s transport! • Well known for eddy formation (can be 200km across!)

  4. Physical Description • Balance of Ekman wind-stress and coastal friction (balance of wind curl and frictional vorticity) • In S.H. : curl + or counterclockwise and friction vorticity – or clockwise • Stommel- Coriolis term varies with latitude, strengthens W. Boundary EAC • Surface EAC also strengthened (some) by deep->shallow shelf

  5. Wind field response drives separation (not New Zealand or bottom topography

  6. Eddies • Geostrophic balance: pressure balances coriolis • Cyclonic clockwise around low-pressure cells and counterclockwise (anticyclonic around high pressure cells) IN S.Hemis!

  7. Upwelling W. coast of Aus doesn’t have wind-driven upwelling • Instead EAC “encroachment” towards coast pushes up isopycnals

  8. References M. Roughan, J.H. Middleton / Continental Shelf Research 22 (2002) 2551–2572 K.R. Ridgway, J.R. Dunn / Progress in Oceanography 56 (2003) 189-222 http://www.cmar.csiro.au/remotesensing/oceancurrents/ http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=15366

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