29 Mar – SA upwelling eases


Firstly, looking at the SST around the country we can see only small changes since last week.

The upwelling in South Australia (where Ekman transport causes cool water to rise to the surface), has eased back a little due to the recent frontal activity. Traditionally the Bonney coast upwelling season runs until May so we can expect the feature to hang around a bit longer.

In the Pilbara, the sea water temperatures have become very hot due to successive days of light winds in the wake of TC Marcus. Looking at the anomaly chart we can see it is up to 2 deg above average. Measurements show SSTs of 31 to 33 deg C.


Looking at a different parameter – salinity. This is the amount of salt in the ocean and you can think of it as the equivalent to humidity in the atmosphere.The recent heavy rain in QLD is affecting the salinity of the surrounding seas. As shown in ROMS eReef there is a lot of fresh water sitting on the top 10 to 12 m of the ocean along the Cairns coast.

Sea Level Anomalies and Ocean Currents

Ex-TC Iris will push up sea level along the QLD coast, as shown in the anomaly plot below. It will operate like a coastally trapped wave. Sea levels may exceed HAT in Noosa today. By tomorrow the wave of higher sea levels will be along the Mackay coast.

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