Archive for March, 2010

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!

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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.

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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.

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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.

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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.

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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.

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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.

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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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late so a quick data update before a fishery glider discussion blog tomorrow

Thursday, March 4th, 2010

It has been a long, but great day with a big celebration of RU27 .  Two elementary schools, 4 deans, and 1 University President, ~40 undergrads, all wanting to geek for oceanography.  A good day, but we have glider flying tonight, so how does it fair?

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The glider is heading cross shore and slightly south.  It is making good progress with storm driven southerly currents decreasing and the glider successfully adjusting to hit the prescribed way-point.

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The decrease in nearshore currents was corrborated with the HF radar codar data.

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The glider data does not show much structure in the vertical, except in the midshelf during the peak storm intensities. .  Except for low density water nearshore largely due to low salinity water, there is no structure in the optical or phytoplankton distributions.

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MARCOOS 2010, Year of the Fish!

Wednesday, March 3rd, 2010

The first MarCOOS glider is deployed for the 2010 field season.  We have deployed ru22 and we will begin a month long journey heading down south to our most excellent partners.  We will add a second glider in the next few weeks to give us a northern view of the Mid-Atlantic shslide11elf.  Both efforts are timed to coincide with NMFS cruises to be conducted over the next month.  The glider deployment was accomplished just prior to the storm arriving on Tuesday night.  Since the storm arrival the surface currents have increased significantly in intensity as seen by the MARCOOS HF radar network.

Over the last 12 hours the currents in southern Mid-Atlantic bite have increased, and therefore it is not surprising that the glider progress has been limited, and the strong currents are carrying it to the south, slightly off it current waypoint offshore.  However given the strong currents the glider is making good progress. The glider shows some minor physical structure.  The major feature is a plume of low salinity water in nearshore waters.  Temperature shows very little variability and shows some minimal structure.

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The glider temperatures agree with the available SST imagery.  Heavy cloud cover has limited our remote sensing this week.  But generally, what good images we did have, show cold temperatures on the shelf with the coldest waters found near-shore associated with the low salinity water.  The absolute temperatures measured by the satellites and the glider are in good agreement.

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The low salinity water has enhanced colored dissolved organic matter, however there is no indication yet of much structure in the phytoplankton communities, therefore we are in  a good position to capture the spring bloom in the coming weeks depending on the seasonal warming trends.  Those warming trends,,, I am ready for!  Highest chlorophyll is  found at depth near-shore and optical backscatter (data not shown) shows no structure.  So while the storm was whipped up big currents it has not yet resuspended the sea floor.  Something to follow over the next day.

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More tomorrow, lets see what the end of the storm brings us!

RU27 Celebration- Complete Atlantic Ocean Survey Proposal

Wednesday, March 3rd, 2010

For our next project we plan to send gliders around the whole Atlantic Ocean and even around the world!

Here are some screenshots of our potential glider paths (yellow) along with the currents we are going to ride (red)...

We will travel around the ACC and therefore around the world!

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Another glider will sail the South Atlantic Gyre and over the Equatorial Currents!

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The Amazon and Orinoco Rivers have plumes that spew high nutrient freshwater into the ocean so this is a good place to study!

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Don't forget the North Atlantic Gyre, the Gulf Stream, and 26.5N!

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And there is still a lot to be learned about heat transfer and climate changes in the Arctic!

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