All posts by eterrill

5/19/2012 and 5/20/2012 Final Dye Release REMUS Ops

REMUS operations starting ~1.5 hours before max ebb were conducted during the 5/19 and 5/20 dye releases.  Conditions were rough during the 5/19 mission outside of the inlet and no dye was visible during REMUS ops.  However comparison plots of river Colored Dissolved Organic Matter (CDOM) versus Rhodamine concentrations show that the dye was present, just at low concentrations (~0.5 ppb).  The mission was designed to track the advecting river plume from the inlet mouth to the river plume extent observed from earlier missions (~ 1.2 km offshore).  Mission time was ~3.5 hrs.

5/19/2012 Observed CDOM and Rhodamine concentrations

The same mission was performed during the dye release on 5/20/2012.  Significantly higher concentrations of dye (6 – 10 ppb) were advected outside of the inlet and were observed in the evolving river plume.

5/16/2012 and 5/17/2012 River Plume Extent Monitoring Missions

5/16/2012 River plume extent as measured by CDOM during strong south wind conditions.

 

5/17/2012 River plume extent as measured by CDOM during minimal wind conditions.

Here are the results of two AUV missions performed on 5/16 and 5/17 to observe the offshore extent of the river plume during max ebb using elevated CDOM signatures to define the boundaries of  the plume.  The 5/16 mission was performed during strong southerly wind conditions (blowing directly into the inlet) while the 5/17 mission was performed during minimal wind conditions.  Both missions extend to 1km offshore.  You’ll notice how defined the river jet is during the 5/17 mission and how the plume extends beyond our survey lines.  In contrast, it appears the strong wind conditions during the 5/16 mission suppressed the offshore extent of the plume and pushed it in a southwesterly direction.  It’s also interesting to see the impact the wind conditions have on the mixing of the plume.  The high wind event on 5/16 diluted the plume significantly (colorbar range: 6 to 10 ppb) when compared to the low  wind event on 5/17 where the river plume saw consistent CDOM levels of ~13 ppb as it is advected offshore.

 

5/8/2012 Hyperspectral Image/REMUS overlay

Hello everyone, just wanted to pass along some of the work the SIO CORDC group has been performing offshore with the REMUS AUV.  On 5/8/2012 we ran a REMUS mission supporting the Guza dye release.  We’ve overlaid the Rhodamine signature observed by our AUV on the hyperspectral image taken at 17:39UTC (courtesy of Luc Lenain and Nick Statom). The REMUS was deployed at 17:20UTC and started near the entrance to the new channel and went in a southwesterly direction towards the beach.  It reached the end of this leg at ~17:40UTC(when the image was taken).  You can see from the image that this first leg was outside of the dye signature which corresponded with our observations  The REMUS then performs a mow the law pattern across the inlet.  We first encountered dye at ~17:46UTC and continued measuring the plume until the end of the mission at ~19:00UTC.

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