Archive for the ‘Across the Pond’ Category

RU25 Turns West

Sunday, February 8th, 2009

RU25 hit its waypoint and turned west, flying along the southern coast of Puerto Rico.  We are about 111 km away from the rendezvous point with the R/V Bold.  RU25 is flying well, making about 30 km/day.  Thats a bit faster than we travel with the shallow gliders.  So we should hit the point in about 4 days, arriving about Feb 12 or 13.  R/V Bold is due in the area about Feb 15.

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RU17 Accomplishments

Thursday, November 6th, 2008

Tale of the Tape

 

RU17 was deployed on May 21, 2008 and  was within 20 km of the Azores EEZ line when we lost communications on October 28, 2008. The Rutgers students, technical staff and scientists flew RU17 a record breaking distance of 5,700.59 km.  We spent 160 days at sea, which translates to 22 weeks and 6 days, or 5 months and 1 week depending on your preferred measure of time.  There is no Guinness Book for glider statistics, so we have to rely on the public websites we can find. Based on that search, it looks like we share the duration/distance records with our friends at the University of Washington.  Glider RU17 now holds the world record for the longest distance mission for an autonomous underwater glider – 5,700 km.  A University of Washington Seaglider holds the world record for the longest duration mission – 7 months. 

 

 

Education

 

The primary purpose of this flight was education.  We where challenged by NOAA to fly a glider across the Atlantic on an inspirational flight that entrained students. Funding for this purpose was provided through donations from Rutgers Alumni. The private funds were used to build RU17, which was christened The Scarlet Knight by the Rutgers President in honor of the Rutgers-wide involvement that not only crossed campuses, schools and departments, but also crossed generations of students in the Rutgers family.

 

Over the course of building RU17, the test Flight to Halifax, and the Across the Pond experience, undergraduate involvement in the Coastal Ocean Observation Lab has increased by an order of magnitude.  We typically had 1 or 2 undergraduates in the Lab on a regular basis, including a record setting 3 undergraduates in 1994. Now, depending on how you count, we have been 10 and 20 undergraduates working in the Lab.

 

We see the undergraduate students are seeking new opportunities earlier in their careers.  In the past the majority of students came to us during their Junior year.  Occasionally we would entrain the rare Sophomore, a lucky break because we would both benefit from the opportunity to spend two summers together. Now, attracted by the grand scale of international glider missions, we are even pulling in Freshmen through the various Intro to Oceanography courses and Freshman seminars that we use as feeders.  Workstudy students are seeking us out during the school year. Traditional summer internships are being used to attract students from outside Rutgers, and to send Rutgers students abroad. Some Seniors are staying with us through the summer after graduation before they move on. Some of the new Freshman will have spent 4 years working with us in the Lab over the course of their undergraduate careers.  The students are seeking both the hands-on research opportunities and the camaraderie of a group project that RU17 provided.  They are prompting us to teach more mid-level undergraduate courses. Our traditional capstone courses, for example, the first year graduate course in Physical Oceanography, are still being taken, but the capstone course I now recommend for their final semester is Communicating Ocean Science, an NSF sponsored class developed by Lawrence Hall of Science. The course introduces them to modern educational theory, it provides hand-on opportunities to practice what they learn at Liberty Science Center, and they use that experience as a basis for mentoring the younger multi-disciplinary students in the lab. Even after graduation, we see that the students use the new tools available to them, like video IM and Skype to stay in touch, and to field questions from younger students that are just starting out.

 

What did the students do during this project?  We had several small teams or sometimes individuals contributing to a common goal. Two students helped with the glider build itself.  Two worked on determining and improving the flight characteristics of RU17, including work on the flight characteristics of the extended payload bay, energy savings on communications and trim battery movements, and optimizing the gains on the Digifin for improved steering.  Two worked on the CODAR network in the U.S. as the take off point, one went to Spain to work on their CODAR network as a potential landing point.  One worked on path planning and the new Google Earth and Google Maps interfaces.  Another worked on the webpage interface describing what we are doing.  During the summer, the more senior level students took full control of the flight planning and waypoint changes.  During the fall semester, the younger students came in and filled their shoes.

 

Science

 

The most interesting scientific discovery of this mission has been the interaction of the glider with the upper ocean biological communities of the central North Atlantic. After leaving the Gulf Stream region and heading east of the Grand Banks of Newfoundland, we noted a decrease in glider speed on both upcasts and downcasts, resulting in fewer undulations per 6 hour segment. The suspected cause is biofouling, since the speed decrease was slow and steady for a period of about a month before it leveled off at a slower but steady speed.

 

The new discovery for us was the difference in the day-night behavior of the upcasts and downcasts.  The upcasts were sensitive to the day night cycle, downcasts were not.  There were many times when the upcast speed at night was much slower than the upcast speed during the day.  Many times at night we would have trouble making it to the top of an undulation.  The glider would be slowed to a stop, and would have to turn around and go back down before trying again to ascend.  Yet throughout the mission, downcast speeds showed no day-night variation. Interactions with either remoras and squid were suggested as possible explanations.  We have seen Remoras attached to gliders in the past, and we know they are negatively buoyant, which could explain the glider’s reluctance to climb if a remora was attached.  Remoras also use their vision to hunt for food, so its been suggested that they may prefer hitching a ride on a glider at night when they have nothing better to do. 

 

The other interesting part was that the occurrence of slow nighttime upcasts appeared to vary in space and time.  There was one eddy in particular that we saw the slow upcasts whenever we were in it.  Another cycle we noticed followed the new moon.  There were two new moons that RU17 started flying in a tight circle as if something had grabbed onto one side or the other. During one full moon it circled to the left, the other it circled to the right. It was suggested that bioluminescence was making the glider very visible during the new moon, and the glowing glider was attracting squid. Assuming something was attached to the glider, we tried a new procedure to fly the glider backwards, pulling water in the nose to make it heavy but shifting the batteries all the way back so that it sank tail first.

 

 

Partnership

 

The flight of RU17 was conducted in the enduring spirit of the National Ocean Partnership Program. In effect, it launched an unfunded International Ocean Partnership Program that united a community within the U.S. and across the Atlantic. Having a glider deployed at sea motivated collaborations that may otherwise have taken years to develop. Path planning for RU17 required data and forecasts, and operational centers with existing products were eager to contribute to the success of the mission.  The University of Maine provided a link to their satellite data when the Rutgers acquisition system went down and required repairs.  A similar satellite receiving station in the Canaries provided local coverage on the European side.  The NASA Ocean Color Web provided access to the global MODIS dataset for SST and Chlorophyll that filled the gap between the higher resolution direct broadcast data acquired on either side of the Atlantic.  The Altimetry products generated by the University of Colorado, especially the geostrophic currents, were in constant use. Ocean model forecasts were provided by the Naval Oceanographic Command and by our partners in Spain.  The NOAA National Hurricane Center and Oceanweather websites provided wind and wave forecasts.  The international Argo program provided subsurface temperature and salinity profiles for ballasting and flight planning.

 

All the above datasets were combined in a Google Earth interface that was built by students and hardened by research programmers at Rutgers. The purpose was to overlay datasets and glider positions for mission planning and waypoint selection.  Software was developed to go directly from the Google Earth mouse clicks to the glider waypoint files that sit in the glider’s Dockserver mailbox waiting to be sent at the next surfacing. The Google Earth interface proved to be extremely popular with bloggers and pilots.  It has already been transferred to other glider operators throughout the U.S.  It was especially well received by the NAVO glider pilots at Stennis Space Center. They used the interface to mission plan for gliders deployed in two Navy Exercises, BALTOPS with NATO and RIMPAC in the Pacific. At the recent Integrated Ocean Observing System (IOOS) Mid Atlantic Coastal Ocean Observing Regional Association (MACOORA) annual meeting, the interface was one of three adopted by the data management team for implementation during year 2 of MACOORA’s Mid Atlantic Regional Coastal Ocean Observing System (MARCOOS).

 

Training

 

As part of our IOOS Mid-Atlantic Regional Coastal Ocean Observing System (MARCOOS), we started glider flights that ran from state to state in the Mid-Atlantic. Regular gliders flights are now maintained between the U. Massachusetts-Dartmouth and Rutgers, and between Rutgers and U. Maryland / U. North Carolina.  At the semi-annual MARCOOS meeting in the fall of 2007, it was determined that an advanced glider training course was required to maintain this network.  Rutgers developed the Glider School 102 as a follow-on to the Webb Research Glider 101 course. It was first taught in the intersession before the start of the Spring 2008 semester so that all the undergraduates preparing for the upcoming test Flight to Halifax and the eventual flight across the Atlantic could take the course.   They were joined by our IOOS partners, a few glider pilots from NAVO, and some glider operators from Plymouth, England. One of the undergraduates from the U. Maryland that participated in the course later applied for a NSF RIOS summer internship and ended up spending the summer with us flying RU17.  

 

Interest in the Glider Training 102 course also expanded with the Flight to Halifax and the subsequent flight of RU17.  The course was given twice more, once in the spring and again in the summer, as training for additional NAVO glider pilots.  During the class, the NAVO pilots started using the same Google Earth interface to fly RU01 in the Baltic that we were using to fly RU17 in the Atlantic. With our growing connections in Europe, we were invited by the European Glider Organization (EGO) to join them in a European Glider School conducted in Italy at the NATO facility in the fall. 

 

With the rapid expansion of glider operations in the U.S., Europe and Australia, the community is going to need more people training in the operation, maintenance and use of gliders for ocean research and operations. Last year two seniors graduated from our lab. One went to work in the Caymans on NOAA projects.  The other went to Georgia Tech to work with a young faculty advisor starting a new glider lab.  On their last visit, NAVO posted job advertisements in the lab. They are developing a significant glider capability, and they will be needing new people.  They are especially interested in the students that graduate from our lab, and are willing to pay for their Masters degrees if they head down to NAVO after they finish the undergraduate program at Rutgers.

 

Technology

 

RU17 served as a test case for three major changes on the Standard Slocum Glider.  Any of these changes could be tested with dedicated flights in our Mid-Atlantic testbed.  With RU17 we were able to leverage the tests into one long-duration mission.

 

This was the longest duration test to date of the new Digifin developed as part of the glider hardening work for ONR.  The earlier style fins were more susceptible to damage.  The Digifin design is more compact and strong enough to be grabbed without breaking.  It performed well the entire trip, continuing to call in even during the highest seas, and remained tunable throughout the mission as flight characteristics changed. 

 

The Lithium Batteries were tested for a NOAA NOPP project to install a kinetic Fluorescence, Induction and Relaxation (FIRe) sensor on a glider. For the techno-folks, the FIRe sensor measures the quantum yield of stable charge separation at photo system II.  For the rest of us, this provides an extremely sensitive proxy for phytoplankton physiological status.  In other words, are the forests of the sea healthy. Light sources used by the FIRe sensor require a lot more power than most sensors, so Lithium batteries are strong option for envisioned long-term deployments of the FIRe.

 

The extended payload bay was tested for future deployments at the NSF LTER located on the Antarctic Peninsula. The distance between the U.S. station in Palmer and the British station in Rothera is to far for a standard glider on Alkaline Batteries.  Lithiums are difficult to ship and don’t like the cold. Using the space inside the extended payload bay for additional Alkaline batteries, it is now theoretically possible to cover the full distance between Palmer and Rothera with a single deployment. The flight of RU17 demonstrates that the extended payload bay is a viable option when longer duration missions are required.

 

In the process of conducting this mission, engineering observations were continuously shared with Webb Research, the designer and manufacturer of Slocum gliders. This feedback helped Webb identify and prioritize software and hardware upgrades that impact all gliders. Specific examples include positive control of the buoyancy pump when a downward inflection is initiated at depth (this prevents the high water pressure from generating heat by pushing the pump in faster than intended), additional energy savings modes and a range of new gain values for the control of the Digifin, the ability to cross UTM navigation zones without restarting a mission, the design of new wing rails for attaching the wings to extended payload bays, etc, etc.  This feedback loop is how we have operated with Webb Research as a NOPP partnership initiated in 1998. Electrochem, the manufacturer of the Lithium Batteries, has now joined this partnership.

 

Public Outreach

 

Our students serve as ambassadors for Rutgers and for ocean science and technology. They brought gliders to high schools around the state and explained how young students at Rutgers can get involved. They flew the gliders in the pond on campus during the public Agricultural Field Day, attracting news media coverage.  The Flight to Halifax attracted coverage in the U.S. and Canada, and the midway point in the flight across the pond produced an Associated Press article that was printed in hundreds of newspapers around the world.  Chip and I were at the RIMPAC exercise in Hawaii, walking a glider down the public dock to a deployment vessel.  We were surprised that everyone knew what it was, commenting how it looked just like the one that was trying to cross the Atlantic.  In another example, we were at the Liberty Science Center, teaching a class in their Delta Lab, a lab set up to look like the Rutgers COOLroom.  The middle school students we met that day told us Rutgers was famous for football, basketball and gliders.

 

Conclusion

 

This was a risky mission. Everyone knew that.  We also knew that we would learn a lot more by trying than by staying at home.

 

We tried once.  We learned a lot. We'll try again in the Spring.

A Great Mission Comes to an End

Saturday, November 1st, 2008

We just spent the last week at the European Glider Organization (EGO) meeting in La Spezia, Italy.  It was early Monday morning, the day after we arrived, that RU17 woke us up in the middle of the night with a call to our blackberries. Dockserver had just sent us the warning "Glider: ru17 Event: ABORT". 

A glider abort doesn't necessarilly mean the sky is falling. What it does mean is that the glider figured out that something is not right, and rather than trying to deal with the problem alone, the glider decides to come to the surface so we can work on it together. But the message Dockserver was relaying to us from RU17 wasn't good.  In glider-speak, RU17 sent the following line with the abort:

ABORT HISTORY: last abort cause: MS_ABORT_LEAK

One of RU17's internal sensors had detected a leak, and it was aborting the mission to return to the surface until we told it otherwise. 

Now the leak detect sensors are very sensitive, and with good reason.  Any small amount of seawater can cause electrical systems to short and fail.  We have seen leaks before, and have continued to fly the glider, adjusting the flight characteristics to shallow up the dives and climbs to keep whatever water drops that were rolling around inside away from the electronics.  In the past we have been able to keep a glider flying towards its recovery point by this method.   It all depends on your glider's location when you find the leak and how much risk you are willing to accept.  If it is a local deployment, we just keep the glider at the surface and send a boat out the next day - minizing risk.  If it is far away, you sometimes have to accept the risk and fly towards a pickup point that is within range.  In the process of doing this, we have learned the flying tricks of monitoring the vacuum and leak detect voltages to minimize impact on the electronics.

RU17 then sent us a second message from the surface that included the following lines.

   sensor:m_vacuum(inHg)=8.12776288306713           5.158 secs ago
   sensor:m_leakdetect_voltage(volts)=1.05079366266727     52.628 secs ago

The good news was the internal vacuum was holding.  That meant the airbag was holding.  The airbag has to inflate and deflate for every surfacing.  Thats a lot of motion over 5 months with the potential for wear points.  If we have a leak, the airbag is always the first suspect.  But the internal vacuum was holding, so the airbag was likely intact.  That's very good, because the airbag is also our life ring. Just like your lifejacket, it gives you that extra added buoyancy to keep your head (in our case the communication antenna) above water. 

The bad news was the leak detect voltage was down to 1.05.  Usually the voltage on the leak detect sensor is rock solid around 2.48 volts. Any rolling drop of water may move it a few hundreths or even a few tenths. But here it was already down to 1.05.   Even though we know there is no direct correlation between the amount of water inside and the magnitude of the voltage drop, and that by definition, any leak in a submarine at sea is bad, the severity of this drop in voltage stopped me dead. That one number spelled trouble. 

Since we now had RU17 at the surface, we may as well spend a little Iridium money and start downloading the engineering files to determine what happened, and when the leak detect was triggered. The crew at Rutgers downloaded the most recent "dbd" file from RU17 with all the engineering data.   Here is the plot they sent to us in Italy.  It shows a trace of depth (black) and leak detect voltage in red.  Note that the leak detect is multiplied by 10 so it can be displayed on the same axis.  The plot indicates that as RU17 started this segment, it was heading down towards 100 m depth and the leak detect voltage remained constant at 2.48 volts.  RU17 hit the inflection point at about 98 m, and started heading back up.  About 11 minutes into the ascent, at a depth of about 47 m, the leak detect voltage changes, and within 2 minutes drops to about 1.1 to 1.05.  RU17 triggers a leak detect abort, and heads to the surface.

With this news the rescue mission was on.   It was now monday in Europe and we could not have been in a better place.  The entire European glider community was assembled in Italy.  Clayton Jones from Webb Research was with us. We downloaded more data from RU17 to try to get a better handle on why we were leaking.  Nothing in the previous records looked odd.  Emanuel Coelho from NRL Stennis was with us in Italy, and he helped us with contacts in the Azores.  The University of the Azores research vessel, the R/V Arquipelago (http://www.horta.uac.pt/) was perfect and was available. It was a 1.5 day steam from its home port to RU17's present position. 

RU17 was drifting north. The altimtery below showed the situation.  It was in the northward currents between a warm eddy to the east and a cold eddy to the west.  It would continue to drift north and then whip around one of these eddies.  If it stayed with the warm eddy, it would whip around closer to the Azores.  If it stayed with the cold eddy, it would drift farther away.  So drift was setting a time frame for us.  We had about a week before RU17 would drift to the northern side of these eddies and turn east or west. Since RU17 looked to be favoring the cold eddy and the turn to the east, we wanted to be out there before it made that turn.  Chip was in the U.S. and could fly out to the Azores to meet the boat.  Dave was in Italy with us and a full load of glider recovery gear for the EGO glider school. He could leave from Italy and head to the Azores.  Whoever got there first would head out.

That left us on shore to monitor the trends.  But the news was not good.  The leak detect was not holding steady.  Instead it continued to drop.  By tuesday it was down to 0.42 volts.  We were getting very good at coming up with scenarios that could explain the continuing drop in voltage that did not include the obvious explanation that more and more water was somehow getting in.   We were at dinner on tuesday night when Hugh called from Rutgers.  We had lost communications with RU17.  Oscar and Josh later told me that in that one second, they watched me age 10 years. RU17, my constant companion for 5 months, had gone silent.  And we were quickly running out of tricks.

Our next hope was the emergency ballast weight.  If RU17 looses both communications and gps signals, it assumes it is somehow stuck underwater, and it blows its emergency ballast weight.  500 grams of lift.  In a world measured in grams, this provides a big push to the surface.  If the seawater had not damaged RU17's electronics, and it could still think, in 16 hours it would eject its ballast weight and return to the surface. 

It was a restless night for most.  Email traffic persisted through the night.  People would wake up, trade emails, and try to get back to sleep.  No sign.

The 16 hour time period without communications was set to expire the next day, Wednesday, just before the lunch break at the EGO meeting in Italy.  We all gathered around the Dockserver station we set up for NATO for use in the glider training school.  16 hours came. no comms from RU17.  17 hours came.  no comms.  We went to lunch.

There were still several scenarios that could have RU17 at the surface, but with a damaged Iridium satellite phone so it could not call us.  In this case the emergency ARGOS location system is on a separate circut, and the next time a satellite passed overhead, we could get an emergency transmission with a location. We have also found gliders by this method in the past. The Argos system gives you an approximate location within a few kilometers with a few hour delay.  Anyone trying to find something in the ocean with this information knows how difficult it is.  But once you get close, we have something called a Gonio. Its a direction finding antenna that you tune to the ARGOS broadcast frequency that you can then use to steer the boat in to close the last few kilometers on the glider.  We keep 2 Gonios in the lab for just this purpose.  They have paid for themselves many times over. But after another full day of monitoring ARGOS, still no reports from RU17.

The EGO meeting and glider school ended yesterday, and now we are back home in the States. We'll continue to watch and wait through the weekend.  Yes, stranger things have happened.  We always keep in mind the Oregon State experience where a lost glider suddenly reappeared several days later and phoned home.  We'll let these next few days pass, and see if we get anything.  If nothing new happens, we'll likely close out this mission sometime early next week.   At that point we'll celebrate RU17's many successes, and start the build on the next glider that our students will launch towards Europe in 2009.

 

 

 

 

 

Off to La Spezia

Saturday, October 25th, 2008

Tonight we hop the pond to Italy.  We are heading to the European Glider Organization meeting. Glider talks, glider training. We'll work on plans for the RU17 turn around in the Azores, and the continuation of the trip to Spain.

RU17 is in a low velocity region, but the current is heading north. You can see the warm water in between the two eddies heading north. The currents seen by the glider are smaller than what we expect from the altimetry. The smaller currents mean we need to use our glider velocity to head east.  So we turned RU17 to the ESE.  We hope the small southward component will get us into the target eddy that is to our southeast.  The new waypoint is on the northern edge of this eddy.  The SST front says the western edge of this eddy is about 135 km away.  And the point we are heading to is about 245 km away.  We are flying slow now, down to about 10 cm/sec.  Usual trouble at night, we don't always make it to the top of our undulations and have to head back down.  But its real cloudy in the area, and the moon is going into is final phases before the new moon, so we always see a deterioration in performance with the new moon.

We'll keep working these eddies, trying to get to the Azores before finals.  If we don;t beat finals, we may have to wait for the intercession between semesters.

 

 

The Recovery of RU22

Wednesday, October 22nd, 2008

Missed my usual morning rounds of RU17 today.  But no worries, the students are driving. Veterans of the Flight to Halifax are on the job. 

Today we were more concerned with RU22 (above).  It was offshore Virginia.  It just completed the Fall sampling run for the southern half of our Mid-Atlantic region for IOOS. We were running low on batteries, currents where pushing us south towards the Gulf Stream faster than we could fly, and a low over Nova Scotia was sending big waves our way.  The forescast was bad as far forward as they forecast. Tom (UMaryland) and Mike (UNC) rented a bigger boat (they are both fans of the small, fast recovery vessels), and were heading out for retrival today, the best of the all bad weather days this week. Many of us were at the annual meeting of our IOOS Regional Association in Fall River, Massachusetts, looking out the window at gray skies and strong winds.  Tom and Mike were going to head down the coast close to shore until they reached the same latitude as the glider, then head out into the waves.  We watched on our blackberry's while they took the hits all morning. Just after lunch, the code message was sent.  RU22 - Bear in the Igloo!  Glider-speak for RU22 was recovered and safe on deck.  At the IOOS meeting, the UMass, RU, and UMaryland glider teams were all smiles. The IOOS glider sampling was successfully coordinated with the fall NOAA Fisheries surveys, and the last glider was coming home.  We had our assimilation dataset for a winter of hindcast model experiments. While we celebrated, Tom and Mike had to battle back against even bigger waves to get back home. We heard the story later in the day at dinner.  We owe them new Mustang suits.

Meanwhile, way out in the North Atlantic, RU17 is in the cold eddy centered near 40.5 N, 36.5 W, now crossing over to the eastern side of that eddy. Our next target is the warm eddy to our southeast centered near 38.5 N, 33.5 W.

The Altimetry above says we should already be feeling the currents to the north, but the glider current time series plot below says thats not the case.  The glider says the currents are still running to the east. So our students have the waypoint set to the south.  The combination of the eastward current and the southward glider velocity gives us the desired path to the southeast.

When will we hit the northward flowing side of the eddy?  From the Satellite Sea Surface Temperature map below there is a band of warm water extending to the north alont 35 W.  That is probably the northward currents we see in the altimetry. if we measure the distance, we are about 30 km from the edge of this warm band.  We should close that distance in a couple of days. Farther to the east, between 34 W and Flores (FLW), we see colder water to the north of 39.5 N is likely associated with the clockwise eddy circulation centered near 40.75 N, 32.75 W.  So we will want to stay south of that front.

About 435 km to Flores.

5 Months at Sea

Tuesday, October 21st, 2008

RU17, named The Scarlet Knight for good luck, has now spent 5 months at sea, traveling 5600 km in the process.  We started these student missions with the Flight to Halifax (also one of our blog sites) back on March 7, 2008.  Backed up by a world-class ocean observatory, the students ranged from Seniors to Freshman. Some have graduated and are on to jobs with NOAA or graduate school, and the Freshman that started with us are now the Sophomores steering us from eddy to eddy to the Azores. The plot below shows how RU17 is crossing the vast abyssal plain of the Atlantic and is approaching the Mid-Atlantic Ridge. The Azores is on the ridge, with Flores, our target island, on the western side.  This morning we are 450 km from Flores. 

 

 

Zooming in on the track and the satellite Sea Surface Temperature image,  we are running parallel to a front that lies to our southwest.  Our objective has been to stay north of this front as we crossed between the two cold eddies.

Current speeds are oscillating but with in increasing trend, and are to the east or southeast, consistent with RU17 being on the southern side of the northern cold eddy.

Below is the satellite altimetry showing RU17 flying between the two cold eddies, staying closer to the northern eddy.  The really good news is the two warm eddies that lie to our east between 34 W and 32 W. On Sunday, these two eddies were strongly interacting, and had formed a wall that RU17 would have to go around.  On monday they started pulling apart, and today, they look like distinct warm eddies.  It gives us a clear path to Flores.  We head southeast and pick up a push from the southern warm eddy.  Students will make the change after class this morning.

 

To call the Azores

Monday, October 20th, 2008

So here is the process to call internationally from a Rutgers phone. 

To call outside the RU campus-99

To call internationally-011

Country code for the Azores-352

Then area code and number 

 

So saying the number we wanted to call was area code 123 and number 456-789, the full number would be 

99-011-352-123-456-789. 

(The numbers in the azores only have 6 digits as opposed to our 7)

 

The calm between the eddies.

Sunday, October 19th, 2008

RU17 is now located in the middle of the interaction zone between the two cold eddies, one centered to our northeast, the other centered to our southwest.  The eddy to the northeast, the one we are closer to, is weakening.

Currents reported by RU17 in this region are week, and changing direction over the last day and a half.  The changing direction is likely due to the rotating inertial currents.  The inertial currents mostly just loop you in a circle, while the glider uses its own speed to make progress toward the waypoint.

National Hurricane Center dropped Tropical Storm Omar from its tracking webpage. Waves from Omar are down today.  The look to be running about 10 ft.

 

500 Kilometers to the Azores

Saturday, October 18th, 2008

RU17 is flying southeast just north of a front in the Sea Surface Temperature.  We've outlined the front with a white line.

Currents are slowly increasing in speed and are still running to the southeast.

The two pieces of evidence we have above indicate that RU17 is likely on the southern side of the cold eddy centered near 40.5 N. 36.5 W in the satellite altimetery below.  The SST front could be associated with the other cold eddy to our southwest.  Our objective is to fly eastward between these two cold eddies, staying in the northern cold eddy to take advantage of its currents to the east. 

We'll likely continue on this heading for the weekend, crossing through the interaction zone and staying in the northern eddy. Once across the center, we'll start heading south as far as we can in anticipation of crossing the northward flowing currents between 36 W and 35 W.   The thin white line is the google earth ruler.  It says the distance to Flores just dropped below 500 km.  Everyday, the ocean gets a few kilometers smaller.

 

Tropical Storm Tuesday

Saturday, October 18th, 2008

RU17 is currently located near 40 N, 37 W, heading east.  Tropical Storm Omar is at 34 N, 51 W, moving northeast at 13 knots. Yep, Omar is heading directly at The Scarlet Knight, due to arrive about tuesday.  Our third tropical storm this trip.

Tropical Storm force winds are likely in our region.  Forecast Discussion on the NOAA National Hurricane Center website has the highest winds concentrated on the southeast side of of the storm, the side that will hit RU17 if Omar continues on this path.

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Signficant Wave hieghts in Omar right now are running in the 15-25 foot range.  Big waves again.  We'll do the usual rigging for storms - stay a littler deeper on our top inflection points.  Unlike the many gliders we purposely fly into storms and hurricanes, we like to keep RU17 away from the rough treatment.  We have little idea what RU17 actually looks like 5 months into this voyage, so we are minimizing risk where we can.

Below is the track of RU17 and the forecast track of Omar overlaid on the satellite Sea Surface Temperature.  Now we have 2 reasons to run to the east as fast as possible, first to avoid Omar, and second to get ourselves out to the Azores and back before final exams.

Below is the cloud front that OMAR is running along.  We hope this front moves east and clears the skies over RU17.   We are right on the edge of the cloud front, and Omar looks to be running along it.