Nor Easter waves are blow­ing in much more

Sydney Arena - - FRONT PAGE -

North East­erly waves known as Nor Easters are be­com­ing more fre­quent.

The East Aus­tralian Cur­rent (EAC) that brings trop­i­cal warm wa­ter down from Queens­land onto Syd­ney beaches is get­ting stronger.

A rise in warmer wa­ter has re­sulted in an up­surge of trop­i­cal fish and soft coral species in Syd­ney Har­bour.

In the south­ern hemi­sphere, the sea­wa­ter layer moves to the left of the wind di­rec­tion - due to the Earth’s ro­ta­tion - known as the Co­ri­o­lis ef­fect.

The hot land tem­per­a­tures of sum­mer bring in sus­tained Nor Easter on­shore breezes, and the warm top layer starts drift­ing at right an­gles to the pre­vail­ing wind.

This over­all weather con- di­tion has had the net ef­fect of bring­ing up cold, nutri­ent rich wa­ter from the deeper ocean to re­place it.

It usu­ally lasts for a few days with cold wa­ter mixed with the very warm North West­erly brings about stun­ing sea mists.

When the southerly buster fi­nally ar­rives the warm wa­ter is pushed back on­shore and onto Tahiti’s back.

In 2007 a pro­longed freez­ing wa­ter event was caused by a gi­ant eddy the size of Tas­ma­nia, si­t­u­ated about 100 kilo­me­ters off­shore of Syd­ney that was swirling around with a full ro­ta­tion of 10 days.

At its cen­tre the eddy caused an up swelling of very cold wa­ter from depths of al­most 1000 me­tres that spun around hit­ting the coast.

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