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Glider data for July 22, 2010

July 22nd, 2010 1 comment

We have seven gliders flying in the Gulf.  All looks well and they are all making good progress in their respective surveys.  We are keeping an eye on the tropical depression which is likely to enter the Gulf on the weekend.The straight yellow line is some artifact and rest assured does not mean one of the gliders has been hijacked.

Looking at the NAVO gliders, we see one glider (sg135) has headed offshore and is swinging east towards Florida, and if lucky we might be able to rendevous with the Spray/WHOI glider.  The data from the offshore glider shows a relatively constant stable pyconcline and a decrease in optical backscatter.  There is a subsurface chlorophyll maximum with CDOM enhanced at depth.  The NAVO glider that is closer to shore, shows similar features.

The iRobot/APL Seaglider continues it high resolution survey near the oil spill site.  The glider shows a continue decrease in the mid-water CDOM.  Subsurface deep optical backscatter continues to show impressive complexity.  Note that the enhanced backscatter is much deeper the mid-water CDOM maximum, but is coincident with a deep water CDOM maxima. There is a noteable exception to this in the last day with a mid-water peak in optical backscatter at ~275m. Lowest oxygen values are not associated with the CDOM and optical backscatter maxima.

Some beautiful images collected by the Spray/WHOI glider.  The glider entered into the eddy and has since then headed east and broken through the eddy wall heading towards Florida.  The depth of the eddy is evident to be around 250m.  The strong zonal current velocities entering and exiting the eddy are easy to see.  The backscatter signals, assuming they are a proxy for critters, show that the biomass concentrations were lower in the deep eddy.

The three gliders on the West coast of Florida show a consistent story thanks to the great efforts of USF, Mote Marine, and U. Delaware.  The system remains stratified with enhanced optical backscatter, chlorophyll fluorescence and CDOM associated with bottom waters.  The features span the entire water column nearshore where  stratification weaker.  There is variability in the subsurface maxima in chlorophyll fluorescence, optical backscatter and CDOM.  Also the U Del Blue Hen identified a beautiful deepening of the thermocline at ~360 km of its transect which had a dramatic impact on the bio-optical properties of the water column.

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Mid-Week Spatial Update

July 22nd, 2010 No comments

Figure 1: IOOS Overview of the Gulf.  NOAA Slick forecast remains steady.  For the gliders, starting in deepwater, Navy Seaglider 135 is approaching the SIO/WHOI Spray 40. Navy Seaglider 137 and iRobot Seaglider 515 remain near the drill site.  Moving east, the USF Slocum Sam is on the Florida shelf near the north side. The Mote Slocum glider Waldo has joined the UDel Slocum UD134 on the southern shelf of Florida.  Both HF Radar networks are operating.

Figure 2: Zooming into the U-shaped slick, surface currents in the HF Radar network are still heading north from the top of the U to shore.

Figure 3: Lets expand the current coverage to the SABGOM model.  SABGOM sea surface height is shown as color fill, and the surface currents as white arrows.   SABGOM currents are lined up with the western side of the U-shaped slick, all heading northeast.

Figure 4: CSTARS has 3 excellent images of the spill over the last few days.  We overlay all three images here. The darker areas are the slick.

Figure 5: Moving east to the Florida shelf, we see that Slocum UD134 is heading in and is being replaced by Slocum Waldo. Currents over much of the inner to middle shelf are generally offshore, to the west or to the southwest.

Figure 6: Zooming out to the HyCOM model to take a look t the Loop Current Eddy, the Navy Seaglider 135 is riding the strong currents of the northeast out edge as the Spray 40 heads east from the center along the major axis of the elliptical eddy.

Figure 7: And one more image for the east coast.  The Horizon Marine Drifter is on the southern side of a warm feature in the Sea surface temperature and is circulating in a large clockwise pattern in the Sargasso Sea.

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