Archive for March 17th, 2010

The storm, its aftermath and time for glider pick-up planning

Wednesday, March 17th, 2010

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The storm that hit the Mid-Atlantic was dramatic.  In my home town of Princeton, close to 1/3 of the roads were closed.  Power was out for most of the town, and as late as Monday we still had no cable.  While I did not miss the cable TV, it did wiped out my internet access.  This was particularly maddening for this nerd, as I was itching to see what was happening out on the shelf.  During the storm there was significant issues with connectivity to Rutgers.  We are back so lets review the storm impacts and then bring everyone up to date on glider recovery efforts.

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The storm was dramatic as seen by the NOAA buoy offshore Delaware Bay.  The wind data was not available, maybe the wind sensor blew off? But the storm seen as the atmospheric low was accompanied with a significant increase in wave height.  The ~15 ft waves were associated with an average of 8-9s wave period.  That simply translates into a big plate of nasty, and I hope that the nobody was out on the water as this was a dangerous time to be on the water.  But we live in a bold new day, lets check out what our ocean observatory experienced.

The CODAR systems showed the evolution of strong surface currents associated with the strong winds.  The surface currents during the storm peaked to well over 50 cm/s.  Some of the CODAR shore based units were knocked out by the storm.  This lead to some potential biases which may explain the low currents seen over the Hudson canyon during the event; however we have some analysis to conduct. Below is a series of time-series before, during and after the storm.

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The glider despite its effort was advected very rapidly to the south.  We, prior to the storm, had ongoing discussions about the pick-up point for the glider.  There had discussions about whether we pick up the glider north or souith of the Chesapeake Bay.  Our initial thoughts based on the battery curve we were leaning to a northern pick up position.  However the strong push provided by the storm now suggests that we will likely have a southern pick-up location. The depth average current experienced by the glider remains a strong southerly alongshore current.

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The glider collected another amazing storm data set.  Travis Miles, a PhD student at Rutgers, is focused on storm effects, and the data sitting in his bank is great given he is still in his first year of his thesis. Nearshore waters showed low salinity cold water. The density showed  largely well mixed water columns however there was a large cross-shore gradient with low density water near-shore. The chlorophyll showed a great deal of cross shore variability. Offshore the chlorophyll values were enhanced at depth.  The mid shelf showed low chlorophyll in the surface waters, which is interesting as there is no real water mass characteristics which is associated with this low chlorophyll water.  The storm hit when the glider was nearshore and a large resuspension event was observed.  Finally CDOM values were enhanced in the low density near-shore waters but showed no depth dependent variability.

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