Category: silbo (page 1 of 22)

Make Shift Coms with Silbo

After nearly 12 days of being missing in action due to a communications error, the guys up at TWR managed to keep tabs on the whereabouts of Silbo via the Argos Transponder in the tail of the glider.

silbonov12

Silbo we think is in pursuit of either the way point shown in the image above, or one further along the way towards the UK.  We are getting gps hits from the argos every few days so at the next connection we should get a sense of whether the glider is circling the current one as we get pushed by the currents or if it is heading on towards the next one.  For now, the only way to get back control of the glider is for the glider to reset which will kick the communications back in.  Based on how the mission has gone, one of these resets happens every few months, so hopefully by the end of the year we will be able to get Silbo under control once more.

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500 km

Now just 500km from the United Kingdom’s EEZ, Silbo is back to making good progress covering roughly 30 km/day.  A few days ago, we flew through a couple of small eddies that slowed progress a little bit but didn’t bump us too off course.

silbo500

As we make our way closer to the shelf, the way point currently set at 47˚ 15N, 14˚ 45W has us lined up nicely to ride the edge of the eddy system towards our goal

Copernicus Oct 27

Copernicus Oct 27

Over the next few weeks, we will then move the way point to get us around the southern edge of the large eddy and close in on the EEZ around the end of november.  From there, we will then turn on the thruster to move the glider up the shallow shelf on the way to recovery.

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Entering the IBI

Now that Silbo is back in to the favorable currents, the glider has really picked up speed and is once again making good progress towards Europe.   With the way point set yesterday, the glider is cruising along the jet created by the system of eddies that are showing up across all of the models despite being on different levels of structure.

silbo1017copernicus

Copernicus Oct 18

silbo1017oscar

Oscar Oct 18

silbo1017hycom

HYCOM Oct 18

silbo1017rtofs

RTOFS Oct 18

Also over the past few days, Silbo has entered the domain of the Iberian Biscaine and Irish Regional Ocean Model.  This ROM data is fundamentally a high definition version of the Copernicus model output provided to us by our friends Enrique and Marcos from Puertos del Estado who have helped us on both the RU17 and RU27 missions from 2008 and 2009.  We plan on using this HD data to plug into Antonio’s lagrangian visualization so we can see the landscape with an hourly 3km*3km dataset as we close in on the recovery region.

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Back up to speed

After finishing the thruster tests last week and setting the new way point to 47˚, 20˚ , Silbo finally caught a break in the current and picked speed back up.  Through the weekend we started to see numbers again up in the 30 km/day; speeds we havent seen in months!

silbo1017

This afternoon the way point was then pushed further to the south east to 47N, 18W to cut between the cold eddy to the north and the warm eddy to the south east.

As for challenger, on friday the glider was scheduled to leave the states and fly to Australia where it will then be placed on a truck to perth.  Early next month the glider is then slated to be deployed in the eastern Indian ocean  and set forth on its next circumnavigation around the Indian Ocean.

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Persistant Westward Currents

As Silbo continues to try and make his way towards the UK, the westward current that has provided resistance to his progress over the past month continues.

silbo1010

Despite making some progress to the north, eastward progress continues to be slow.  Looking to the models, we are in an area of uncertainty where each of the models shows a cold core signal, but the exactly location varies output to output.

Copernicus 10/10/2016

Copernicus 10/10/2016

HYCOM 10/10/2016

HYCOM 10/10/2016

OSCAR 10/7/2016

OSCAR 10/7/2016

RTOFS 10/10/2016

RTOFS 10/10/2016

 

In other news, on friday RU29 left Rutgers after final checkouts to be shipped to Australia in preparation for its next mission: to circumnavigate the Indian Ocean

Southern Jet

For the past week now, Silbo has been dragged into a very strong current flowing to the south east that has really slowed us down.  The way point was moved further to the east to try and fly perpendicular to the flow in an attempt to cut accross to the other side, however progress has been slow.

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In the plot below, we can see the speed dropping off starting last week and we have our fingers crossed that this will turn arond again soon.

silbo_speed_sept

In other news, Silbo is closing in on 1000km from the United Kingdoms Exclusive Economic Zone.  Once there, the glider will make a hard turn to the north as the thrusters push us along the shallow shelf towards Flamouth, UK.

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5 months at sea

silbo5months

Its hard to believe, but Silbo has been at sea now for 5 months, weaving his way through the Gulf Stream and resulting eddy field.  With more than 4800km in the books, Silbo is nearing the doorstep of the eastern shores of the Atlantic Basin.  Silbo is now just 740km from the Irelands EEZ, 760km from the shelf break, and 1300km from the recovery port of Falmouth, England.

silbo5monthszoom

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Crossing the Mid Atlantic Ridge

For the 3rd time since being deployed out of Iceland in 2011, Silbo has crossed the great Mid Atlantic Ridge!

silbomar

As we prepared for the crossing, the way point was set nearly due directly east of Silbo’s position and the altimeter was activated to prevent an unwanted collision with the underwater mountain range.

However now  that we have emerged from the other side unscathed, I have proposed to move the way point along the same latitude to the north so we can catch the strong northern jet that lies just to our east at a better angle and get more of a push off of it as we head to the north east.

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Coming up on the Mid Atlantic Ridge

Within the next 3 days or so, we plan on having Silbo nearly on top of the Mid Atlantic Ridge:

silbonewwp

In the figure above, the black bathymetric lines indicate the depth at which we are starting to get close to Silbo’s bottom inflection depth (the point at which the glider switches from diving to climbing).  Currently we have the way point resting on the southern edge of what looks to be a fairly safe are to cross –  nearly no areas that reach high enough to put the glider in any danger of striking the sea floor.  To try and increase our chances of making it into this ‘safe zone’ we proposed to move the way point further to the north east so the glider can cut at an angle across the eastward current as we make our approach.

Looking to the models, all 4 representations are agreeing quite well, all showing the signature of a large warm eddy lying to the east of Silbo’s position.  If there prove to be true, the new way point should have no issues allowing the glider to move to the north east and make its way across the Mid Atlantic Ridge and further on towards Europe.

hycom819

HYCOM Forecast 8/19/2016

OSCAR Current pastcast 8/17/2016

OSCAR Current pastcast 8/17/2016

RTOFS Forecast 8/19/2016

RTOFS Forecast 8/19/2016

Copernicus Forecast 8/19/2016

Copernicus Forecast 8/19/2016

 

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Agreement amongst the models

As Silbo pursues the newly given way point out at 44˚ 30 N, 30˚ W we see a nice agreement amongst the forecast models.  Although it is a little hard to see due to the different levels of smoothing used in the three models, Copernicus, HYCOM and RTOFS are all currently showing similar signals in the eddy field that lies ahead that will allow Silbo to continue on the step-like path to the north east we plan to take on our way towards England.

Copernicus Forecast July 20

Copernicus Forecast July 20

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HYCOM Forecast July 20

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RTOFS Forecast July 20

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Step like path proposed week of July 12th that the piloting team plans on taking towards Europe as the mission progresses

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