Archive for the ‘Middle Atlantic Bight’ Category

Hurricane Arthur

Wednesday, July 2nd, 2014

Lets start with the latest forecast track for Arthur:

Arthur 2014 07 02 Full track

And zoom into the Northeast region:

Arthur 2014 07 02 Track Zoom

Eye is forecast to clip Cape Hatteras then accelerate to northwest over deepwater.

Greg passed along the SST anomaly:

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He said it looks to be 2-4 degrees warmer than usual in the Mid Atlantic and Gulf Stream. But thats at the surface.  It is early in the season so the Cold Pool should be very cold and just below a thin thermocline.

Here is the Rutgers coldest dark pixel sst composite:

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This preserves the nearshore upwelling features, and after a big storm, the cooling.  We'll be watching this product evolve as soon as the hurricane clouds are gone.

Arthur looks much more compact Sandy, even more compact than Irene:

Arthur 2014 07 02 clouds

Now with the CODAR network turned on:

Arthur 2014 07 02 CODAR

Lots of prep work on the network today.  5 MHz long range network made fully operational, so with an extra day to prepare, a new 13 MHz was deployed along the Jersey coast to further fill in the space left by Sandy.

 

 

Darwin: The Super Glider

Sunday, October 21st, 2012

Hey all,

Over the past month, there has been a prototype glider roaming the waters off of the Middle Atlantic Bight; Darwin.

Darwin over the years has been a in a way TWR's test glider, and this summer he  continued this legacy as Webb outfitted it with a prototype fluorescence puck to compare with the standard florescence  puck, and a prototype thruster.

The first test being done, is the puck comparison, where the prototype C3 puck is being compared to the Wetlabs ECO Puck which has been used regularly in the Slocum Gliders.  In the past, the Wetlabs ECO Puck has provided a reliable source of collecting data on Chlorophyll, Color Disolved Organic Matter (CDOM) and Back Scatter.  The new Turner C3 Puck has similar sensors including Chlorophyll, Phycoerythrin, CDOM, Turbidity (back scatter), temperature, and depth.

Left: Turner C3 Puck, Right: Wetlabs ECO Puck

The first two preliminary plots I have created, are a subplot comparing the Chlorophyll sensors on each of the pucks and then a concentration plot of the same goal.

 

Both sensors seem to collect the bulk of the data to the same extent, however there are some minor differences, such as picking up data in different areas of the water column in different intensities.

I made a similar plot of Turbidity from the Turner C3 Puck against the Wetlabs ECO Puck's Back Scatter.  This plot again shows that there is a lot of consistency in the bulk of the data, but they also seem to pick up some differences as well.

There will be more of an analysis to come!

Darwin is also equipped with a prototype thruster that can be programmed to turn on and off in different intensities throughout the mission.  This can be incredibly useful in piloting when it comes to getting out of sticky situations such as eddies or unfavorable currents,  reaching an ideal area of sampling quicker, or flying more exact lines when sampling an area for a successful mowing-the-lawn pattern.

As the design of the glider does not leave much room for exterior modifications, the ejection weight had to be moved during installation from its standard orientation.  Below are two images showing the new orientation along with the thruster relaxed and set.

The thruster was tested on two occasions in which 'Bath Tub' profiles were attempted.  An ideal bath tub profile consists of the glider diving to a pre-set depth (in this case 10 m) and the thruster then kicking in causing the glider to cruise, level at depth for a period of time before returning to the surface creating a path that looks like a bath tub.  This was attempted on September 14th and 17th and the results are below:

 

As we can see, the thruster worked, however Darwin was not able to maintain depth as planned.  After recovery, there is some hardware maintenance that must be done to the thruster, and there will also be a software upgrade that will allow the gliders brain to use logic that will help it maintain depth by adjusting pitch.

As Darwin has now been running tests off of the coast of southern NJ for a couple weeks now, Darwin has been making its way back up the coast towards Belmar, NJ where a recovery will take place early this week depending on the weather.  After recovery, the adjustments to the thruster listed above will be made, along with changes to the science payload bay.  After the upgrades are completed, Darwin will be redeployed off of New Jersey and fly the reverse of the track previously flown on its way back up to Teledyne Webb Research's facility in Massachusetts.

 

Nilsen

Start of the 2011 MAB spring sampling season: 4/15/2011

Friday, April 15th, 2011

We are starting of the integrated sampling of the MAB for the year, and after a tardy start, blogging is now beginning using the MARCOOS.

Sea surface temperature show warming in the southern areas of the MARCOOS grid compared to the northern water offshore Massachusetts.  The nearshore waters are indicate high chlorophyll concentrations. There is variable phytoplankton concentrations across the continental shelf, with low values associated the Hudson Shelf valley.

The currents have been variable of the last four days, with surface currents decreasing in the southern region of the MARCOS domain. There is spatial variability with strongest currents off the Massachusetts and associated with the Gulf Stream offshore Cape Hatteras.  The currents are generally declining over the last 4 days.

There are two gliders deployed.  The community deployed a glider 5 days ago and it has conducted a cross shore line off Tuckerton, and has just turned south and will zig zag towards our partners in Maryland. The shelf is now showing slight stratification.  In the mid-shelf of the there are warm temperatures.  Nearshore waters are lower salinity.  Chlorophyll fluorescence is highly variable.  Nearshore the chlorophyll values show highest   concentrations, especially at depth.  The high nearshore values are coincident with the high particle loads.  The offshore waters show high values in the 40-60 isobaths.  The higher values offshore are associated with lower temperatures.

The second glider was launched from Massachusetts on Thursday on the 14th of April.  The temperature data of the small ammount of available data seems to indicate some shelf stratification.  The optics data will be posted on the next call in.

Now from the North!

Tuesday, March 23rd, 2010

A second toast is in order for the IOOS team to the North.  U Mass and Rutgers has launched a glider in the northern grid, and it is making great progress as it is heading south.  The glider is carrying both optics and a CTD.  A great deal of spatial complexity has been revealed.  The glider last night was shipped into shipping lane beavior mode.  This means it is will be not be surfacing very often, 12 hours, and when it does it gets a position fix, and heads back on its way.  The glider also stays deep so as to pass under the ship traffic.

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The salinity data shows a nearshore buoyant plume.  Associated with the near-shore low saline water is enhanced concentrations of particles.  The particles do not appear to be phytoplankton as the fluorescence showed no significant enhancement in these waters.  This suggests that the particulate material is sand, silt, etc.  The chlorophyll exhibits a sub surface bloom offshore the low salinity water.  The phytoplankton concentrations are very high and given their depth would not be visible in satellite imagery. The phytoplankton concentrations offshore are also seen in enhanced optical backscatter. Hopefully clouds will blow out by the midday satellite passes so we can see if the bloom is visible by satellite.

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Great work and a toast to our sea going partners!!

Friday, March 19th, 2010

The call sign for a successful glider recovery came in this mid-morning.  "The bear is in the igloo."

RU22 was recovered with a broken wing and our bet that its nose cone is full of sediment.  We will assess. But tonight we toast the partners who went to sea.  Today we scientists from U. Maryland, U. Mass Dartmoth, Rutgers, and Webb Research all at sea spanning from St. Thomas, to the Chesapeake, to southern New England.  To those sea dogs, we raise a pint and thank you for a great job done!

perfectpint

Operation extraction!

Friday, March 19th, 2010

A quick note and a morning coffee toast to the Maryland partners.  They are hopefully going to recover RU22  today.  The large storm over the last weekend has resulted in a slug of low density water.  This making glider flying problematic as the density is on the border of the range we ballasted the glider for.  So the glider is loiter mode just offshore and lets wish our intrepid Maryland partners good luck.

ru22_100308t2229_100318t1625_marcoos_tsect_map

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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.

ru22_100302t2110_100317t0845_marcoos_zcur_map

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.

ru22_100308t2229_100316t1931_marcoos_sal_xsec-1

ru22_100308t2229_100316t1931_marcoos_temp_xsec

ru22_100308t2229_100316t1931_marcoos_dens_xsec

ru22_100308t2229_100316t1931_marcoos_chla_xsec

ru22_100308t2229_100316t1931_marcoos_bb880_xsec

ru22_100308t2229_100316t1931_marcoos_cdom_xsec1

A calm day, which is always cool

Wednesday, March 10th, 2010

The glider is making good progress towards it's inland waypoint.  We have shut down one of the EcoPucks, the goal here is to conserve power and try make sure we have plenty of power to loiter for recovery.  We shut down the one puck that was only measuring backscatter (a optical proxy for particle type and concentration).  The puck we have kept on, measures one wavelength of backscatter and two wavelengths of fluorescence. Many of the features we saw on the shelf offshore transect.  We see complexity in the offshore temperature, salinity, and chlorophyll.

ru22_100302t2110_100311t0145_marcoos_pos_map1

ru22_100308t2229_100311t0124_marcoos_sal_xsec

ru22_100308t2229_100311t0124_marcoos_temp_xsec

ru22_100308t2229_100311t0124_marcoos_chla_xsec

RU22 makes it turn!

Tuesday, March 9th, 2010

RU22 makes great progress, it has hit the offshore way-point and now is heading inshore.  The progress looks good.  Gaps in the HF radar do not provide the currents at the specific glider position, but  overall despite some spatial heterogeneity the currents look low and not very strong.

ru22_100302t2110_100309t1345_marcoos_pos_map1

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The satellite imagery has been nice given the great sunny 50 degree days. The sunny days show cool water on the shelf.  The warmer waters offshore were encountered by the glider.  Phytoplankton biomass was highest in the cooler near-shore waters.  Also compared to the weekend, the blooms appear to be increasing in intensity.

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Glider data shows the temperatures are isothermal. Consistent with the offshore waters seen by the satellites, the glider temperatures are warmer offshore.  The warmer waters offshore have high salinity values.  The highest backscatter values were encountered during the storm last week.  In contrast, the chlorophyll data shows a great deal of spatial variability with enhanced values offshore. The bloom appears to be increasing with time.

ru22_100302t2110_100308t2229_marcoos_temp_xsec

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Good progress over the weekend!

Sunday, March 7th, 2010

RU22 continues its effective steam across the shelf.  The glider makes good progress to the way-point to the south, and is being supported by shelf-wide circulation which is to the south as seen in the CODAR imargey.  The glider should reach the shelf edge by the beginning of the week.  This is positive given the large number of optical sensors on the glider which has the potential to drain the batteries quickly. Discussion over the weekend has been focused on which glider sensors we turn off first to ensure enough power to make the journey.

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The hydrographic structure the glider has encountered shows nearshore low salinity water and isothermal water properties.  The backscatter showed enhanced magnitudes during the storm.  After the storm optical backscattter dropped and chlorophyll was also low.  No clear features in the physical data suggest a unique water mass was associated with the low chlorophyll water.  After a few days the chlorophyll has increased.  This could be consistent with a post-storm phytoplankton bloom as the water column stabilized.  More to research in the coming days.

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The enhanced chlorophyll is also seen in the ocean color imagery.  The phytoplankton patterns are unique showing major coastal blooms and a second bloom present at the Grand Banks.  The water is still cold water across  the Mid-Atlantic Bight. The chlorophyll measured by satellite and the glider show good agreement.

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