The cool Australian eddy has become giant

Lively Data: April 21, 2008

Sea Level Anomalies (SLA) the 30th December 2007, on the Australian Eastern coasts. Choose Near-real time Data, Global, (Maps of) Sea Level Anomalies, the area and the date. The black line locates the transect used below, in the longitude-time diagram.

Thanks to the watchful eye of satellites including altimeters, a cold eddy is regularly noticed off Sydney (see Lively Data, March 28, 2007: Cool Australian eddies). The eddy has reappeared this year, but with such proportions that it approaches the size of Tasmania. The cold eddies reduce the sea level with troughs around which currents swirling, in a clockwise direction in the Southern Hemisphere (and the opposite occurs in the Northern hemisphere).

Longitude-time diagram of Sea Level Anomalies, between 152.2 °E and 159°E, for the latitude 33°S (located by the black line above) between March 2007 and March 2008. Choose Near-real time Data, Global, (Maps of) Sea Level Anomalies Merged, the kind of diagram in Select view (longitude-time hofmoeller (xt), the latitude (33°S) and West/East borders. Choose the same palette colors than the first figure (-70,70,5).

 

A longitude-time diagram of Sea Level Anomalies using the LAS, shows the evolution of this eddy since our last Lively Data on this subject, in March 2007. The birth of the eddy has been traced to last August, it temporarly become weaker to reappear further off coasts in October. Since this date, it is closer to the coasts while reducing the sea surface. It reached its maximum size at the end of 2007, when its center was reduced by more than 70 cm. The eddy appears to be on the wane now.

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