Post-Storm Bloom Conditions – An Initial Look

Three days after the storm, glider RU16 completed its transect back across the shelf toward the beach.    This section gives us our first complete look at how the inner-shelf was impacted by Hurricane Irene.   For the past week the glider has gone back and forth three times, two before the storm and one after.

The satellite image from the day after Irene shows that the bloom off the south Jersey is now pushed more evenly along the coast.   Also, the highest concentration of cells do not extend as far offshore as what we saw before the storm.

Now we look to the glider to see how the altered surface expression of the bloom extends down into the water column.   One of Irene’s more dramatic impacts in the data is seen in the temperature fields.   We can see a  significant cooling throughout the surface layer with a fully mixed water column in water shallower than 20m (below left).   The timing of the storm is shown as a red dashed line.

For the dissolved oxygen impacts we see a similar mixing in the surface layer.   As the glider made its way inshore underneath the higher cell concentrations seen in the satellite image above, the dissolved oxygen in the surface layer increases.   We also see the the deeper mixed layer is allowing higher oxygen concentration to penetrate closer to the seafloor

Pre-Storm

Post Storm

The distribution of oxygen values in the pre-storm and post-storm sections (above) shows a shift toward the middle of the range.  After the storm there are no observed concentrations below 4 mg/L or above 8 mg/L.  There is still a bi-modal distribution but it is now centered over about 5.2 mg/L and 6.5 mg/L for the bottom and surface layers respectively.   The largest peak in the distribution has also shifted from the lower concentrations of the bottom layer to the higher concentrations of the surface layer.  RU16 will now continue to monitor conditions along this line until it is recovered later next week.

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