May 8th Dye Release Image

The dye release yesterday (May 8th) was very interesting.   The dye release was initiated shortly after slack tide as the water started ebbing.   30 gallons of Rhodamine WT were released in 2:24 min.   As usual the mounted instruments,  the jetskis, NPS/RSMAS crew, REMUS, towed ET array, and the Partenavia were all measuring the dye plume.   At first, as the tide was still not very low, the dye poured down the main channel and then oozed out over the southern shoal.    See the aerial hyperspectral image below (taken at 1339 local time, from Luc Lenain and Nick Statom).     Up the inlet near where the dye was released, the surface dye is very patchy because the dye is released about 3 m above the bed in ~9 m water depth.  At times it seems like the surface dye patch has a periodic signature.   The dye moves offshore of the south-western shoal in jets and squirts.

The nice thing about this image below is that it can be used to quantify Rhodamine dye concentration.   As light is measured across a spectrum of wavelengths, information at absorption and emmision wavelengths of dye will be used to calibrate dye concentration against in situ sensors.

Below are some SLR camera images of the plume at similar stages.   These are useful for providing context but are nowhere near as quantitative.

SLR camera image of the plume shortly after pump turned on. Note the quasi-periodic surface structures (N. Statom)
SLR camera image of dye over the SW shoal. Note similarity with the hyperspectral image (N. Statom)

Update on Dye and Drifter releases

Here is an update on the remaining schedule for drifter and dye releases.

DYE RELEASES:

Thursday: There will be no dye released.   Note, this is a change from the previous schedule.

Friday May 11th:      Begin releasing dye at 0800:   Release dye for 1.5 hrs – (to just before slack).  Sampling on both ebb and flood.

Saturday May 12th:    Begin releasing dye at 0830:   Release dye for 1.5 hrs. Sampling on both ebb and flood.

DRIFTER RELEASES:
May 14-17 (Monday-Thursday)

DYE RELEASES:
May 19-21

APL-UW thermal IR imagery of the New River inlet plume

The imagery above is a preliminary mosaic of the New River inlet plume on May 2, at about 1150 EDT (the companion data to Gordon Farquaharson’s microASAR data in his May 4 post).  Brightness in the image indicates relatively warmer temperatures, and I’ve adjusted the contrast to highlight the plume, making the warmer land white. The plume on this day (due to wind) was shooting north and the plume front(s!) are complicated – including prominent transverse features at N = 3822.5km, E = 286 to 288km. Note there are still kinks in the mapping, so image overlap is not exact, and the camera drift and angular emissivity effects have not been corrected.

5/4/2012 REMUS River Plume Survey (No Dye Release)

REMUS CDOM Observations of the evolving river plume at the beginning of the ebb tide (t=1) and its progression to approximately 3 hours later (t=4). Main Channel has the strongest signature, and the area to the south over the shoal where we have since seen dye plume also shows up. Old Channel signal seen to the far right. Team CORDC RIVET contingent (Eric Terrill, Peter Rogowski, Jeff Campana, Tony de Paolo, Myles Syverud, Joel Hazard, Tom Cook, Billy Middleton)

First ever blog post for me.  The ‘other’ Scripps group has been running the REMUS AUV to characterize inlet dynamics and map the outgoing plume.  Before the dye surveys, we ran a series of missions to survey the naturally occuring optical signals leaving the inlet over an outgoing tide.  Above are cross-sections of CDOM across 4 different transects.  We’ve also run some offshore to onshore transects to characterize how far offshore the plume is advecting and characterize the vertical structure.  Should be interesting to compare with the remote sensing imagery.  -Eric