News Release from the Naval Oceanography Operations Command

For Immediate Release
No. 13-003
131024-N-ZZ99-001

NORFOLK, Va. – Aerographer’s Mate 1st Class (AW/SW/IDW) Gina Hegg navigates the Mid-Atlantic Regional Association Coastal Ocean Observing System (MARACOOS) website. Using real time data assets from a variety of sources, including glider data from the Naval Oceanographic Office, she tracks currents, wave heights, winds and water temperature to accurately forecast for units off the Delmarva Peninsula. (U.S. Navy photo)

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The Mystery of Canyons

Amelia has been deployed for just over 10 days now. She is flying excellently. The first half of her mission of exploring Norfolk Canyon and the Slope Sea has already been completed. She is in the midst of completing her second objective, which is to conduct a detailed survey of Washington Canyon to the north of Norfolk Canyon. (see Amelia’s flight map)

Submarine canyons are very interesting and dramatic geological features. While scientists have extensively studied many canyons, most of these studies have been conducted off the west coast of the U.S.  What is special about Washington Canyon? It’s neither the largest or the widest, it’s not strangely shaped or extra deep, as a matter of fact, it’s about the most ‘average’ submarine canyon off the east coast of the U.S., and that’s precisely why we are studying it. This canyon is representative of many other canyons in Mid-Atlantic region and what we learn here should be applicable to the other east coast canyon systems as well.

Amelia has now crisscrossed Washington Canyon in a couple different directions. What we have learned so far is that the water inside submarine canyons appears to be different than the nearby shelf break region. We see more chlorophyll-a, more color dissolved organic matter, and a higher level optical backscatter. We also see a water mass that resembles a remnant ‘cold pool’ each time we cross the rim of a canyon. The largest batch of this ‘cold pool’ water mass was observed when initially flew into Norfolk Canyon to the south, but is also clearly observed at Washington Canyon. The question is, where did this water mass come from, how does it evolve, and is it unique to canyon regions this time of the year?

To answer that question, Amelia will now fly southward a bit along the shelf break to see exactly just how far away from the canyon does this more productive, ‘cold pool’ like water mass extend. After an along-shelf transect, Amelia will turn offshore once more before heading back up the axis Washington Canyon again to come home. I am very excited by the data she has returned so far and I can’t wait to get my hands on the high resolution data she has stored onboard. The process of sifting through the data and interpreting them will take months to complete.

Right now I am jumping ahead of myself a little bit.  Amelia is still far offshore and in the midst of gathering these data.  While it is still a couple days too early for me to think about the details of her return flight, I know many challenges await her. She will need to exit her natural environment of the slope sea where she glides most gracefully and efficiently. On the shelf, her pump will need to work much more often. Her energy efficiency will rapidly decrease as she heads toward shallower water. Will she be able to make sufficient forward progress on the shelf? Will she have enough battery to get to her recovery waypoint? Have I left her enough reserve to handle a potential autumn storm? These are all unknowns at the moment. She might need the good luck you send her way. I will keep you posted.

You can see her mission’s progress as well as that of RU23′s survey of the New Jersey shelf here: http://marine.rutgers.edu/cool/auvs/index.php

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Amelia’s mission to explore the Mid-Atlantic shelfbreak and the Slope Sea

Amelia deployed off the coast of Virginia. Photo by Sean Fate and Paige Ross.

Greetings! My name is Donglai and I am a physical oceanographer at the Virginia Institute of Marine Science. I want to tell you a bit about Amelia’s Gliderpalooza mission and why she’s named Amelia. Amelia’s mission is to study the shelf-break and the slope sea of the Mid-Atlantic region. Together, they form the boundary between the coastal ocean and the open ocean. Coastal waters on the shelf are of Arctic/riverine origin, whereas waters offshore (i.e. Gulf Stream) are of tropical origin. When they come together in the shelfbreak/slope sea, fascinating and complex phenomenons such as rings, eddies, and streamers can emerge. These energetic features, driven by the differences in their physical properties, appear to dance, twist, and melt into one another. Their presence is ephemeral, no one feature stays for long and they always present a different look. As a physical oceanographer, I ask how do they evolve and how might their interactions might affect the state of the slope sea.

Amelia is built specifically to help address the above question. She is named after Amelia Earhart, the first female to fly solo non-stop across the Atlantic Ocean. Amelia’s technological lineage is that of a deep glider that can go down to a depth of 1000 meters. Amelia however, cannot go that deep, she is rated for 350 meters. In exchange for the loss of deep capability, she gains the ability to fly in the shallower water of the coastal ocean. She can still go deeper than most coastal gliders and her depth range perfectly covers the shelfbreak region and the upper slope. This also happens to be one of the under-studied regions in the ocean. One additional aspect of Amelia that makes her quite special is that she has an afterburner! In fact, she’s a hybrid buoyancy and propeller driven glider. With the propeller on, she can boost her speed to over 1.5 m/s, or four times the speed of a normal glider. This does come at an energy cost but the capability can be very useful when flying in energetic flow situations such as storms and eddies.

Amelia’s first deployment and the simultaneous recovery of RU22 on October 17 went very smoothly, thanks to the collaborative effort of scientists at VIMS, Rutgers University, and University of Maryland. As a matter of fact, a jet flew right overhead and made a loud sonic BOOM as Amelia started her mission. Her story is just beginning, stay tuned!

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The week that was: October 14 – 18, Back to busy, busy, busy

After a couple of weeks highlighted by a couple of recoveries and no deployments, this past week suddenly got very active once again as we watch the transition from our early fall to late fall to early winter waters. Here is a quick summary of the activities:

Amelia Deployed: William and Mary’s Virginia Institute of Marine Science (VIMS), headed by Professor Donglai Gong, deployed Amelia, a glider with a propeller to get it out of sticky situations. More on that deployment to come this week.

Donglai with Amelia prior to deployment

RU22 was picked up by the VIMS gang and returned to Rutgers after a very successful deployment and acquisition of a great dataset from the nor’easter that came through last week. 19C water at the bottom in 39 meters of water? Yep, that’s REALLY warm.

OTN200 was redeployed on the 15th, but had to fly back to shore because of what we suspect is a leaking fluorometer. It will likely be picked up tomorrow (Sunday) morning. The goal is to replace the science instrument bay and redeploy it next week.

Penobscot was picked up this week as noted in the previous blog, but will be redeployed shortly to continue on it’s fall missions.

The big deployment this week was a triple deployment of RU23 and two Navy gliders with members of the NY Times and Discovery Channel’s Daily Planet film crew, who will be making a 5 minute video on Gliderpalooza and the deployments. RU23 and one of the Navy gliders were successfully deployed. The second Navy glider was deployed, recovered, deployed again, and recovered again (we just wanted some practice). Actually, this glider ejected it’s rear weight. This is the first time our group’s experience with 349 deployments that this has happened. We are going to try to figure out the cause this week. In the mean time, RU23 and Navy1 are on their way across the shelf on their missions to map the extent of the cold pool after the nor’easter last week. Here is a link to a video of the deployment: Dual Glider Deployment.

Nilsen Strandskov (Rutgers/MARACOOS), Mike Crowley (Rutgers/MARACOOS), Nikki Beauchamp (Dalhousie/OTN) and Gerhard Kuska (Delaware/MARACOOS) on the triple glider deployment.

Early data from RU23 indicates that the inner shelf is still well mixed since the nor’easter that sat on top of us from Oct 8-12.

The Nor’easter on October 10. Several days of NE winds pushed warm water inshore and created a well mixed ocean within 40 miles of the coast seen from NJ to Virginia.

As RU23 moves slowly offshore, it is obvious that the entire water column is mixed top to bottom

RU23 Salinity also shows a mixed water column, though she is beginning to encounter higher salinity waters.

The map below shows the current deployments. The Navy glider cannot be seen yet, but it will fly the yellow zig zag path out to the shelf and back. That data should be available online later this week.

Current deployments: RU28 is shown in red, Otis in grey, RU23 is following the green triangle (red dots), the Navy glider is moving offshore (east) along the yellow zigzag and Amelia is furthest south moving SE toward the shelf break.

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Penobscot Pit Stop

On Wednesday morning October 16th after 37 days and 730 kilometers of flight, UMaine glider Penobscot was recovered just off Pemaquid Point, west of Penobscot Bay.  Penobscot completed two surveys of the Eastern Maine Coastal Current (EMCC) and en-route spent a few days surveying right beside our UMaine NERACOOS buoys E and I, which bracket the branch of the EMCC we’re investigating.  Penobscot has flown beautifully for us, navigating well even in areas where the surface currents were as high as 0.5 m/s.

Two weeks ago, we narrowly escaped a mid-mission early search and rescue when Penobscot appeared to get tangled on fishing lines in the early hours of the morning and could not make way or leave the surface.  Thankfully, this did happen at the surface where we could talk to Penobscot and where, after a few frantic hours, we managed to break free, presumably aided by surface waves (or curious wildlife…).

This is only a pit stop though.  Penobscot has a short break while we download all its data and make hardware modifications to one of our on-board instruments.   We will then redeploy to continue surveying the coastal current in the region of one of our buoys.

Coming home: Penobscot travelling a little faster than usual in our boat for the final few miles of its trip home. Insert: Penobscot surfaces very co-operatively 150m off the bow.

UMaine glider Penobscot’s Sep 10th- Oct 16th complete survey path

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The Return of OTN200

On the morning of October 15th, OTN200 was redeployed off of Ingomar, NS by Adam and Christena. The somewhat complicated mission plan will take it through Roseway Basin three times, stopping for a run south to the shelf break and back, before returning mid-November. Inexplicably persistent and courageous mosquitoes followed our field team 2 kilometers offshore to ‘oversee’ glider deployment and accompanying water sampling.

OTN200′s proposed track for Round 2

Our last trip through Roseway Basin yielded interesting results related to the scarcity of right whale sightings this year and so we have redoubled our focus on this critical area for October’s deployment. While there have been many warm water depth profiles posted by our southern collaborators, it is still very chilly up on the Scotian Shelf. We try not to play to stereotype, but the cold water regime continues on this side of the border.

Temperature profile from OTN200 scaled similarly to RU23′s temperature plots. Brrr! Vertical temperature variability is likely due to strong tidal currents.

The long weekend (Happy Thanksgiving from Canada!) afforded us the time to offload our VMTs (Vemco Mobile Transceivers) from the September deployments. We struck out in detecting acoustically tagged animals on the south shore of Nova Scotia, but were fortunate near the end of our Halifax run to have detected two of the blue sharks tagged by Brendal Davis’ group (read more about their tagging efforts here). We are informed that the two we detected were Riley (in blue) and Brianna (in green), juvenile females tagged very recently in waters west of our deployment. Efforts will be made to pair our detections up with detections along the fixed receiver line in place off of Halifax, NS. Our VMTs are back on board and listening for this latest deployment.

OTN201′s September track with detections.

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Thursday is looking good!

A short update. Thursday looks to be the start of Gliderpalooza round 2.  We should be deploying a glider out of Wachapreague, VA, 3 out of Atlantic City, NJ, and one out of Halifax, NS. If Mother Nature is nice to us….. more later.

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Gliders have no problems with bad weather, but….

…. people do!

The plan for today was to deploy 4 gliders, including 3 along the NJ coast and 1 along the Virginia coast. Unfortunately Mother Nature is not cooperating.

The great thing about gliders is that you can send them out in a hurricane or nor’easter or storm and get great data. They don’t complain about rough seas, they don’t get seasick, and they never complain. Unfortunately for us to get them into the ocean we need to go out in a boat to deploy them, and the weather this week is not allowing for those deployments, though our Canadian friends well to the north are enjoying better weather and were able to retrieve one today. Below is a plot of recent significant wave heights just off the Delaware coast. We like to deploy in seas with waves under 5 feet. We are nowhere near that now.

Significant wave height from buoy 44009 off the Delaware coast.

Right now it looks like to best chance to get Navy1, Navy2, RU23 and the new VIMS glider deployed will be Tuesday next week. Additionally, OTN201, which was recovered today, will be redeployed next Tuesday as well. Round 2 will officially begin with those deployments.

The gliders in the water are, however, acquiring great data from the current slow moving low pressure system making its way up the east coast. RU22, which is off the coast of Virginia, shows that warm water has been pushed further inshore, to the bottom in 37 meters of water! It’s 19C (66F) on the ocean floor in 120 feet of water! That’s warm! Anyone want to go diving without a wet suit?

Temperature cross section from RU22 showing the downwelling of warm water to the ocean floor well offshore.

CODAR HF-RADAR surface currents below show the strong southwesterly flow of surface water in the mid-Atlantic which is helping to push in warm waters from offshore into the coast. The water piles up and pushes downward along the ocean floor, somewhat like a conveyor belt movement.

HF-RADAR surface currents showing strong currents moving southwesterly throughout the mid-Atlantic.

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Prepare for Round 2!

This week we expect to have 5 more gliders join in the fun. Two return visits from RU23 and OTN200, two new deployments of Navy gliders, and one new deployment from our partners at the Virginia Institute of Marine Science (VIMS). On October 10, the two navy gliders will deploy with RU23 out of Atlantic City NJ. The Navy gliders will likely be tasked on triangles out to the shelf, while 23 stays closer to shore complementing the work that RU28 is doing. On that deployment will likely be several members of the press/TV. It should make for a fun day on the water.  I wonder if they know what seasickness is?

Speaking of press, here is a short list of some articles on Gliderpalooza:

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And then there were 3

We are now approximately half way through the palooza, with12 glider deployments either completed or in progress, with an ever growing amount of distance covered which is now approximately 5000km.

Gliderpalooza deployments to date (October 5). Yes, there is still another month ahead!

Over the course of the last week, several of the gliders completed their Gliderpalooza missions. These include:

OTN200 was a confirmed recovery once we heard “the beaver is in the lodge”. But OTN200’s dry dock days will be short lived as it will be redeployed this coming week. Yes, it is a workhorse or workbeaver.

Blue was recovered on September 26 after completing a near perfect triangle for our modelers to use for assimilation and verification testing. Congrats to the UMass team on that deployment! The data along the shelf slope front shows some amazing subsurface dynamics, not to mention the Chlorophyll spikes in the thermocline (20-50m) throughout the deployment. http://marine.rutgers.edu/cool/auvs/index.php?did=384

Salacia was safely recovered off Charleston South Carolina today. As she is the queen of the sea, scientists saw numerous remoras and baitfish surrounding here when she was picked up. Thanks go out to SeaTow for helping with the pickup. Can’t say enough about SeaTow and the longterm partnerships with them over the last 20 years.

RU23 was recovered on September 27, and like Blue, completed a successful triangle for the modelers to use. The CTD failed during the last 48 hours of it’s mission. This will be quickly replaced as RU23 has a return engagement to continue paloozing next week.

UD275 (aka Otis): This glider has been the primary focus of the UDel and Rutgers teams this week. We lost communications with Otis on Sunday, Sept. 29. After several days of planning, a search and rescue mission was sent for him on Friday October 4. Doug Levin of Washington College and Art Trembanis of UDelaware graciously donated their expertise and equipment to do a side-scan search of where we think Otis could have been hung up on the bottom. The MARACOOS HF-RADAR and modeling teams put together forecasts of the currents and potential drift of the glider over time. The Side scan imagery yesterday of the area was pretty impressive. We could see all the detail of the sand waves and ancient shorelines! Unfortunately, we didn’t find Otis. Our best guess is that Otis is in some strange software state drifting around, or it was hit and disabled. As of today, Otis has been missing 7 days. The one bright spot is that the record for a glider going missing before rising from the ashes again is on the order of 6 weeks. We hope to get one of those middle of the night calls from him that he has resurfaced.

So those are complete, but what is to come?

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