Archive for June, 2011

Keeping an eye both above and below

Thursday, June 30th, 2011

Hey all,

Well we are still chugging along, and making good time at that!  Yesterday afternoon, Challenger 1 was given a new waypoint back to the south east, and now we are heading almost directly south at an astonishing 1.35 km/hr (which is excellent for a glider) and have gone about 24.5 km since yesterdays afternoon surfacing.

There has been recent discussion about the currents that the glider is recording.  It seems that no matter which way we are moving, we are recording currents that are going about 90 degrees to the right, which haven't always correlated with what the Hycom model is telling us, and is also pretty suspicious in itself.  Within the next couple of days, we will begin flying with a program called current correction set on to try and correct for what the glider thinks the currents are doing and see if that makes any changes to our heading.

Next, we continued looking to the depths to make sure we stay a safe distance from the bottom.  Today I overlayed the bathymetry map from geomapapp onto google earth so we could see it along with the hycom currents and current glider position.  The cross section I took follows the path the glider would be drifting if we were continuing to follow the current and even in this scenario, the shallowest water is still about 1300m.  So we should be fine for the time being if we continue to dive to 1000m depths.

Shannon Harrison and Dave Kaminsky who have both been involved with the COOL room for many years also contributed to the path planning this morning; thus increasing our global collaboration to include our fellow Rutgers students currently interning all the way over in Perth, Australia at the University of Western Australia where they are helping with research in the Oceans Institute in conjunction with the Australian National Facility for Ocean Gliders and the Integrated Marine Observing System.  They pointed out that there are two general directions of the currents which they depicted with the two blue arrows, the red line dividing the two.  Both having experience in piloting gliders, they advised us to continue looking at the movement of the eddies to see how they progress now so we may plan for when we reach the areas with the most movement.

Another thing we must worry about, is the intensity and direction of the eddies changing largely unpredictably due to storms.  Due to the kinetic energy of the wind, the eddies may grow in both size and intensity in the presence of a storms.  And just our luck, Antonio pointed out today that there is a massive storm system headed our way!  To minimize the storms interference, we may take a look at our operational depth and make sure we are not rising up into waters that may be disruptive until we need to surface.  We will also need to keep an eye on our current models as the storm may cause eddies to change before the model has a chance to update.  This may lead to some discrepancies along the way.

Lastly I (Nilsen) would just like to apologize to our dear friends Antonio, The University of Las Palmas at Gran Canaria, and PLOCAN for any confusion I may have caused.  I accidentally gave Antonio's work credit to PLOCAN in two of my previous posts, when his official affiliation is actually with U. Las Palmas GC.  However, U. Las Palmas GC does collaborate quite regularly with PLOCAN.  So again guys my greatest apologies!

-Nilsen & Oliver

Aiming East to go South

Wednesday, June 29th, 2011

Hey all,

So today we we continued our global collaboration to choose our path for Challenger 1.  In order to conserve battery power, we have now turned off our altimeter.  This will causes us to use less battery power which is crucial while we are still in the first days of the mission flying in frigid Arctic water.  However, we are now flying solely off of bathymetry maps.  Luckily, between U. Las Palmas Gran Canaria and Rutgers, we have found two different models showing the depth of the sea floor in the area we are flying that correlate very well and so have boosted our confidence allowing us to do away with the altimeter at least for now.

 

Bathymetry Map provided by Antonio

 

 

In the above images, the top being from Antonio and University of Las Palmas GC and the bottom two being from Rutgers, we can see that we should be safe of running aground if we stay in the channel between the Mid-Atlantic Ridge and the rise off of Europe.  Zooming in, it looks like we will have to avoid the line going diagonal south in the image below (starting from about 24) if we want to continue safely flying to 1000m without our altimeter on.

 

So after studying the bottom, now we must take into account where the water is going and how the glider is flying.  After moving the waypoint yesterday to try and get us moving further south, our speed dropped from between 1.2-1.35 km/hr to .87km/hr.  We seem to have hit a small eddy whose currents had started sweeping us west.

Antonio provided another similar model that showed that we are in the midst of a few cold eddies that if we maneuver around correctly, we will be able to shoot ourselves further south and find a few more currents that will aid us along the way.

Sea Surface Height and Currents Provided by Antonio

Another thing which may prove piloting this glider to be a little bit tricky, is we have some reason to believe that Challenger 1's compass may be slightly off and could possibly be over estimating the power of the currents resulting in a heading error.  On Monday, back before the waypoint was changed, we calculated that our heading was off by about 40 degrees, which from previous experience could be explained by the compass and an over estimation of currents.  Today, we recalculated after finding the loss of speed, and found that today we were off by a little under 50 degrees which again could be a result of the currents that we were now fighting.  Taking this into account along with the eddies we are now trying to navigate, we will have to move our waypoint further east to effectively get Challenger 1 on its way south.  During the next surfacing we will give the new point to the south east and see how we fly.

Finally, yesterday evening back home in the COOL room, visitors from The Ocean Observatories Initiative or OOI, were given a tour of our facilities by Scott.  Our visitors are some of the leading names in modern day Oceanography, and through OOI are revolutionizing the way we study the global ocean.

 

 

-Nilsen

Living on the Edge

Tuesday, June 28th, 2011

Hey all,

Well quite a bit has happened since we last checked in, so lets jump back to Friday afternoon.

After giving us quite a scare less than a day into its mission where Challenger 1 missed its call home due to technical failures on our end, the glider almost mockingly called in once an hour for over 10 strait hours Friday afternoon through Saturday morning.  But it wasn't just trying to prove a point to its parents like an obnoxious teenager, it was running a series of tests.  The results allowed Challenger 1 to auto tune it's own ballast settings, which will allow for it to most effectively navigate the depths with its saw tooth flight pattern.  This nifty trick may prove to be very beneficial as we move south to waters with different densities that may require a re ballasting.

The next great update is that on Sunday, Challenger 1 crossed the shelf break and is now flying in deep water.  After the first dive to 1000m, we were already seeing improvements in the flight pattern.  We are flying straighter, meaning that by flying deeper we are being effected less by the surface currents which are moving in a North- West direction (the exact opposite of where we want).  Flying to 1000m depths also really helps us out with battery power.  Going that deep, we only make 2 oscillations over about an 8 hr period which means we are going further along our track while only having to make the internal movements necessary to make climbs or dives twice between surfacings (compared to 6 times when we were in shallower waters).

Today we began our global collaboration to choose waypoints to pilot the glider now that testing is done and we are truly on our way.  Antonio and our friends at University Las Palmas Gran Canaria gave us some great advise on either taking a route that takes us directly to the Canaries, or further out west towards the Azores.  The path heading directly to the Canaries will offer us a more direct route through waters that are very well known and modeled.  The other option will put us in less sampled waters where we will very likely find discrepancies in our models, similar to what we saw during the 27 mission.  The westerly route also leaves us the option of swinging by our old service station, The Azores, if we run into any real trouble along our journey.  There is a draw back however of that this will add about 15% to our journey and may lead to problems if we don't have sufficient battery.

Our decision for the time being is to just focus on getting south out of the colder waters for now.  The sooner we do this the better, as the cold waters tend to cause our batteries to be drained much faster than if we were in warmer waters.  The good news is that we are moving at break neck speeds!  Typically the gliders we have worked with in the past have gone an average around 1km/hr.  Challenger 1 however has been recording speeds up to 1.35km/hr!  Hopefully if we continue to make good time, we will get out to safer waters and we can continue on our historic journey.

Finally we have a quick update on the conditions Challenger 1 is facing:

The glider is flying smoothly and will now be surfacing every six to eight hours. In this picture you can see her slow but inevitable descent from colder Northern waters into the ever-warming waters of her Southern location.

Here's a picture of the shipping routes in our general path, the coast is clear for now. As expected, there is a lot of activity along the East of our path but we'll have Silbo navigate efficiently through whatever comes our way.

-Nilsen & Oliver

Current Conditions

Saturday, June 25th, 2011

Hi everyone,

Just a brief, simple update on Silbo.

Silbo's Path as of the 25th

Lot of Eddys

The first image is a picture of Silbo's path so far as of 11:52am, June 25th. The second is a zoomed-out version of the first, as you can see, the closer we get to the Canary Islands, the stronger the currents (larger arrows) and the prevalence of eddys  increases (large orange-red swirls). Piloting Silbo through these eddys is crucial because should we get caught in one, we'll have to fight its pull, which will drain our battery and possibly send us off course. There is also a SSH (sea surface height) overlay on top of the second image. Blue-green waters in Silbo's prospective area, a good sign of relatively calm waters.

Overview of the North Atlantic Ocean

Here's an image of the North Atlantic Ocean with a temperature overlay. It's difficult to see the eddys here but once again, we're trying to avoid the "darker black swirls." But, it's easy to see the goal of the first leg of the Challenger Mission, flying from the dark blue, cold  Arctic waters to the red, warmer waters to the South.

 

These final two pictures are profiles sent back from Silbo. The smooth lines in the first picture indicate that Silbo is cruising smoothly and the second image is that of the data that Silbo is currently collecting.

-Oliver

Fractal (cold) liquid meccano

Saturday, June 25th, 2011
Buen día a todos !
Enclosed find the thermocline depths field. Only a little area SE Iceland (a warm eddy), locates the thermocline to 250-300 m. The rest of the domain shows upper thermoclines in front of the Silbo path. We could adjust the critic thermocline depth (up of the yoyo depth) when silbo flies in operational way out of the in shore iceland waters area.  We would avoid additional upper thermoclines that could affect its speed.

Fig 1. Thermocline depth field. N Atlantic. 24th june 11.

 

However, the most interesting remark is related the SSHa field.

Fig 2. SSHa field. N Atlantic. 24 jun 11.

The eddies are organized/ordered in scale and sign from the centroid to the border of this incredible liquid meccano. It changes the sign of the gears (eddies) alternatively, and increases the size (submeso->mesoscalar) from the centroid to the border again.
Fig 3.- Fractal liquid cold meccano.
Silbo will fly the Western sector of this incredible feature. He could take advantage of the Cold eddy (the Western side) located South him, or, otherword, the Eastern border of the warm eddy SW him.
I expect you enjoy it !!
un abrazo a todos !
Antonio G.Ramos

BLOOD, SWEAT AND TEARS….

Friday, June 24th, 2011

Buenos días a todos !

Firstable I would like to thanks the invitation to follow learning and enjoying with all of you, great team. Secondly, I would like to congrat the SIlbo launching team for his incredible job. Third, dont worry about this title, since it is only simple metaphore of this particular, and fascinant, ocean domain. We have largely fought with the NW Mediterranean convective cell since 2007. They are the queens of the non linear effects of the ocean.  We call them the EPIDERMIC PORES OF GAIA.

However, if there is an example in the ocean of the term -CONVECTION- this, the N Atlantic domain, is simply -the Area-.. Our  Gulf Stream (RU27 mission highway), transports the heat to this NE area amd liberates it to the atmosphere. It avoids a strong deplection of the Temperture (SWEAT). Otherwise the hole area would be permanently frozen (SST filed today in the Figure 1).

Fig 1. SST Fields (NOAA/MODIS) in the NE Atlantic. 24 jun 2011.

However, there is another second and critic effect. The cold water (more salted and dense) sunks iniating the thermohaline circulation around the hole global ocean, transporting heat and chemical equilibrium. Finally it surfaces at the end of the belt, in the gulf stream again.  The veins and arteries of Gaia. (BLOOD). (Salinity field today in Fig 2).

Fig 2. Salinity fields NCOM. NEW Atlantic. 24 jun 11.

And finally there is another additional effect. The surface topography deplects and the strong atmosphere - ocean CO2 gradients determine strong changes of the CO2 partial pressure. When the convective ceell is active (INSPIRATION, cold water in the middle, strong negative sea surface height anomaly), it introduces a great quantitty of CO2 in the ocean. When the convective cell relaxs like right now (EXPIRATION, warm water in the surface, small difference of the dinamic topography) this CO2 is trapped by the primary producers to convert it in biomass. For that, it has to be associated with the vertical mixing during the autumn-winter (high concentrations of nutrients in the upper photic  waters). Ther is another supply of nutirents coming from the  thaw (?) of the ice during the spring-summer leg. (SSHa field today in Fig 3).

Fig 3. SSHa NLOM field. N Atlantic. 24 jun 11.

 

This primary producers sunk (TEARS), transporting M and E to the deeper ocean. Look the incredible concentration of the potential future "tears" in form of phytoplankton blooms in this area. We have got used to work in the intertropical belt of the 3 oceans, so recording concentrations of chla arising to 34 mg/m3 is really shocking, but fascinant (Fig 4). I would imagine to silbo when dive-climb the epipelagic domain (100 m) feeling like "indiana jones in the middle of the forest cutting at right and left to follow on !!" (:)).

 

Fig 4. N Atlantic garden. MODIS Chl a fields. 24 Jun 2011.

In spite of the HYPEREUTROPIC character of the North Atlantic domain, the convection determines another imoportant point that it is really important for this mission. The pathplan designed for SIlbo sails W of any Regional Ocean Model Domain of Europe (Mersea, Eseoo, NOC, Myocean..). That means (nothing new under the sun), that we would have to fly Silbo with global models (hycom,..) only. Layered in z levels or non layered, they reproduced (soft some inconsitences) to be goods with RU17, 27 and Cook missions.

A convective area (the kingdom of non linear effects) where good and solids RegionaOceanModels forecasting  sometimes fails, will be an incognite. However, as Nielsen posted some days ago, the signal of the gulf stream flowing toward the right side of the Silbo nose will be intesive and clear. the first months... We would have to look for the eastern side of the warm eddies, or the western side of the cold eddies: Stronger gradients, better currents to the South. Considering all the points before I assume and run the risk to present this (figure 5). The TOTAL current field. We have a good cold signal S Silbo, and he can sail the W border to find S oriented currents.

Figura 5. Total current NCOM field. N Atlantic. 24 Jun 11.

 

Finally, as COOK and RU27, Silbo is heading a liquid meccano (sic) again. The dynamic topography is not very intense (-20 cm, +20 cm) But it seems to organize  as usual. Conforming an incredible liquid meccano of cold eddies sorrounded of warm eddies or the inverse. At different meso and submeso scales (fig 6).

N Atlantic Liquid Meccano. 24 jun 11.

As always, force, wind, sea and honor all, and thanks again to my incredible ULPGC team.

Antonio G. Ramos, Division of Robotic and Computational Oceanography,

University of Las Palmas de Gran Canaria.

 

 

 

Communication Breakdown

Friday, June 24th, 2011

So you know when you're sitting by the phone desperately waiting for it to ring?  Hours and hours pass by as it gets later into the night and still nothing.  Sorry Mom and Dad... I think I finally know what I've put you through over the years.

Challenger 1 made it through its first 12 hrs at sea yesterday as it began making its way south.  However after its surfacing last night around 7pm local/11pm GMT, we lost communications with it until about 9 this morning.  Through my experience with gliders, not making contact for over 14 hrs usually isn't a good thing.  The concerned feeling didn't improve either after I checked the satellite coverage for the region.

 

[Back when I was working on the 27 mission, I devised an algorithm to make predictions on whether Scarlet would be able to call in.  Using Gpredict (top) I could track the Iridium Satellites that the phone in the tail of a Slocum Glider call in to with.  Combining the position of the satellites with the surface conditions of the water collected by the glider (middle) and the wave height forecast from oceanweather.com (bottom), I created a sort of Green, Yellow and Red light prediction method that proved to be pretty consoling when 27 wouldn't call in on schedule]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ben and our friends at Teledyne Webb then saved the day when they emailed us this morning explaining that everything with the glider is fine and that the reason for no comms was that the network and modem were down back home thus not able to receive Challenger 1's call.  So the glider then continued on with the way point it had been previously given until its next surfacing time when it called in this morning around 9.   After making a few adjustments to try and conserve battery power as best we could, Ben punched in a new way point and set it on its way.

-Nilsen

Sentinel 1 & Challenger 1

Thursday, June 23rd, 2011

An historic day.

Today, June 23, 2011, is the first day at sea for the growing global partnership that has just embarked on the first phase of the Challenger Mission.  Followers from previous missions will know the history. It began on December 9, 2009, in Baiona, Spain, at the landfall celebration for RU27, the first underwater glider to cross an ocean basin. Rick Spinrad challenged the U.S.-Spanish partnership to go back to sea. To build even longer duration gliders.  To entrain even more partners and schools.  And to revisit the historic track of the H.M.S. Challenger, the first circumnavigation of the globe for science.

So today, after spending 2010 supporting the U.S. response to the oil spill in the Gulf of Mexico, we are back at sea on another long-duration mission of discovery.  This glider, owned by Teledyne Webb Research, is our first long-duration test flight in preparation for the globally coordinated mission we hope someday will include about 15 gliders simultaneously covering different segments of the H.M.S. Challenger's track.

This time we have chosen a difficult route.  Instead of our usual east-west route where we remain in temperate waters, we are flying north-south from arctic to tropical waters. Our path is from Iceland to the Canaries, a distance of about 4,000 km.

Another difference this time - the students are distributed around the globe. They are stationed in Spain with Carlos, Antonio or Enrique, with us in the U.S., or with our new partners in Australia. Through student exchange programs, they are now visiting each other's labs. Most of the pathplanning and blog entries for the next several months will come straight from these students, some of whom are now veterans of up to 4 previous long-duration missions.

A memorable moment in 2009 was when the student glider pilots chose Baiona, Spain for Ru27's landfall. Their choice was based on Baiona's history as the port where the Pinta first returned in 1493.  We were especially pleased when the students chose to nickname the present glider Challenger 1.  The name is a reference back to Hank Stommel's science fiction story on the global Slocum Mission,

http://www.tos.org/oceanography/issues/issue_archive/issue_pdfs/2_1/2.1_stommel.pdf

where the first glider deployed by the students in the attic of the Bigelow Building in Woods Hole was named Sentinel 1.

So today, with this launch, the global mission envisioned by Hank Stommel, invigorated by Rick Spinrad, and made possible by Teledyne Webb Research, has begun. We hope you enjoy the ride.

The Bear is About!

Thursday, June 23rd, 2011

Hey all,

First of all, we would just like to thank Scott and Oscar for the great dedicatory post from yesterday.  Second, this morning we received the email from our friends up in Iceland telling us the glider is now in the water.  At 1pm (9am in NJ), Ben Allsup of Teledyne sent us the email "The Bear is About" indicating the glider has entered the water.  The deployment crew consisted of Chris DeCollibus from Teledyne Webb Research, Alvaro Lorenzo from PLOCAN, and Arnar Steingrimsson of Teledyne Gavia.  They left from Grindavik, Iceland this morning and went about 10km south in the ship Oddur V Gislason.

After reaching an area where the depths came to about 130 meters, Challenger 1 was deployed and began running its test missions.  The first of which was a single dive to 100 meters and the second being a 4 dive mission expecting to take close to 4 hrs.  If these tests go well, the glider will be left in the water and will begin its journey south to the Canaries.  Our friends at Teledyne will be maintaining control of the glider through the weekend to make sure everything is in order, but next week they will be handed over to our team here at Rutgers.

Nilsen


Change of plans!!!

Thursday, June 23rd, 2011

Hey everyone! Just a quick update: the ocean weather for the long-term forecast is looking pretty stormy, so we're pushing the glider deployments to THIS SUNDAY! We'll be going out early Sunday morning (June 26) to deploy the 2 Seagliders for long-duration missions (about 5 months) that we'll be using the data from for our research, and doing some day-long tests on 2 other Seagliders (we will recover those at the end of the day). We will also be rendezvousing with U209, the Slocum glider we deployed a couple weeks ago, to make an adjustment to the science sensors.

We'll be going out to Perth Canyon, about 36 miles off the coast of Perth, Australia.

We'll have another blog shortly after the deployments, once the gliders are well under control and on their way!

Dave & Shannon