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.