Category: silbo (Page 15 of 22)

Hey All,

In just a few hours our crew is setting sail for Challenger’s recovery.  The last of our team will be touching down on the island shortly where they will then board the vessel and sail out to the glider.  Since we last updated, we have moved the waypoint to the south towards our rendezvous point.

There is a prime window tomorrow that we are aiming to run our operation.  It is projected to be benevolent conditions for recovery with the waves are around 1-2m, calm winds, and minimal shipping traffic. Looking at the image below provided by Antonio, there is actually a band of calm conditions that runs straight through the Azores providing us with near perfect conditions for our operation.

The waves also seem to follow a similar pattern to the wind as we find ourselves in a corridor with less favorable conditions to both the north and south yet smooth sailing in the vicinity of the Azores.

After departing early tomorrow morning from the port of Ponta Delgada on the island of Sao Miguel, they will head around the east of the island to rendezvous with Challenger just to the North.  As of this evening, Challenger is about 66km from port (~3 hr boat trip).  Once Challenger is brought on board the ship, he will return to the facilities back in Ponta Delgada where we hope the problem causing the leak detect to be triggered will be easily diagnosed and be an easy fix.  If this is the case, we hope to redeploy Challenger friday and send him on his way towards the Canaries and La Gomera.  If this is not the case, parts will be shipped over and Challenger will be put on hiatus until we are confident he is ready to continue his journey.

We wish our team the best of luck tomorrow and Force Wind Sea & Honor to all!

Lauren Cooney, Antonio Ramos, Oliver Ho & Nilsen Strandskov

Hey All,

So Challenger has been closing in on Sao Miguel over the past couple of days as we get ready to recover..

As of this afternoon Challenger is about 80 km from port, or about a 4 hr boat ride (granted the ship is going 10 nautical mph).  However the closer we get, the risk of having an unfriendly encounter with boat traffic increases.  Because of this, we have moved the way point due west of Challenger’s location and added a way point back to the east that way Challenger will spend some time going between the way points to buy our scientists some time.

We hope that by Wednesday, Challenger will be on his way back towards the way point to the east so that the boat and take a short trip around the western side of Sao Miguel and pick the glider up and back back to shore as soon as we can.  Weather wise it still looks as if Wednesday will be prime recovery window to be followed up by a further inspection of the glider and hopefully a redeployment on Friday with our next window of opportunity.  But for now we wait as the team makes their final preparations to get out to the island and put this rescue mission into action.

Force Wind Sea & Honor

Lauren Cooney, Antonio Ramos & Nilsen Strandskov

Hey All,

As we arrange for Challenger’s recovery on shore, our little glider continues progress towards Sao Miguel.  However, the elements are proving to be relentless and refuse to let up.

Figure 1: Storm as of 11/11/11

Challenger is in the midst of yet another storm that has stirred up the seas causing an inertial oscillation near the surface that has been pushing him around.  Because we are now diving to 300m to avoid the intense pressures at depth that have caused our previous two leaks, we are now more likely to be effected by the storm as we are spending more time in waters towards the surface.

Figure 2: Challenger 1 making good progress despite a storm

To help combat any inertial oscillations and to get us back towards shore as fast as possible, we have been flying with full buoyancy.  Flying at the higher intensity, although keeping us flying relatively straight, is very inefficient energy wise and so we have turned it off as of this afternoon.  Because of this we will most likely see more of a drift to the north as we get pushed by the currents.

Figure 3: Challenger 1: just over 100km from the Port of Ponta Delgada

Below we have a dissection of the water column provided by Antonio and ULPGC, showing the currents (Figure 4) and the North-South components (Figure 5) at the surface, 100m, 200m and 300m depths.  Below that in Figure 6 we see a nice association between the movement on the surface waters and the sea surface height (and continuing correlation at depth).

Figure 4: Currents around The Azores at the Surface, 100m, 200m and 300m depths

Figure 5: N-S flow at the Surface, 100m, 200m and 300m depths

Figure 6: Sea Surface Height with the Surface Currents overlayed

Another fascinating point is that beginning a few days back, Challenger discovered a patch of very salty water at depth, depicted by the orange blob in the bottom right corner of Figure 7.  This is the outflow of water from the Mediterranean.  Water in the Mediterranean has a much higher level of salinity due to higher levels of evaporation than fresh water inputs.  This water then can be traced as it flows into the North Atlantic for thousands of kilometers.  In Figure 8 and 9, we have Sea Salinity at the Surface, 200m, 500m, 800m, 900m, 1000, and 1200m courtesy of Antonio and ULPGC.

Figure 7: Salinity Data Collected by Silbo. Beginning with early November there is a strong anamoly at depth

Figure 8: Salinity at Surface, 200m, 500m, and 800m

Figure 9: Salinity at 900m, 1000m, 1200m and Time Series from Challenger's Journey

Finally, I would just like to mention what our current plan is for recovery of our brave little droid.  As we are in the North Atlantic in the middle of storm season, there are windows that are ideal and ones that are not.  We had an original window we were looking at of Saturday the 12th (tomorrow) where the forecast called for clear skies and relatively calm seas.  However, finding a boat, facilities and plane tickets out to the Azores can be difficult (especially on such short notice), and so the next reasonable meteorological window that allowed us to get access to all of the resources needed  lands us on Wednesday Nov. 16th.  The recovery team will be leaving the Port of Ponta Delgada, Sao Miguel where the 32 ft fishing boat, Alabote (seen in Figure 10) is available to us.  Time of departure will be decided when we get closer to the mission, but when the team returns to land, Challenger will get checked out and hopefully be able to be put back in the water as soon as possible.

Figure 10: Alabote Fishing Boat

The recovery will hopefully not take too long to sail out and back as by Wednesday we wont be too far off shore.  As of this evening, Challenger is 97km from shore

Figure 11: Challenger's progress towards recovery. 97km and 5 days away from recovery

As always Force Wind Sea and Honor all and especially to Challenger

Lauren Cooney, Antonio Ramos & Nilsen Strandskov

Hey All,

So the past day has been extremely hectic…

Yesterday, we had been investigating our options for our mission: recover or continue.  We had opened the options to flying to Sao Miguel for recovery, continuing on our journey but sticking close to the Azores for a possible recovery from Santa Maria, continuing and keeping a recovery at Madeira, or pushing our way to La Gomera in the Canaries.

One point that had risen was that we had used more battery over the past few days pulling the data off the glider, running tests, and flying shallow than we would flying normally.  After doing a rough analysis of battery power left, we potentially can cover between 1300 and 2300km.  The lower end of this estimate really cut it close on whether or not we would be able to make it to the Canaries.  Because of this, we had began to run tests flying deeper to see if the leak detect will go off again (basing that the leak will occur at extreme depths).  By flying deeper and adding more oscillations between surfacings, we can cover more distance with less battery usage and possibly draw out how far we can go.  So far today we have dove to 600m on a single yo and are going to strive for 2 yos at 600m.

While running these tests, we moved the way point to the east in an attempt to get some better progress as we make our way south, however it looks like the currents are so strong going to the North (courtesy of the cold eddy in the vicinity) that we were pushed to the north during the last segment (seen in the picture above).

Challenger then continued on his way after here until morning when we tried to push his limits further by diving to 650m.  Our battle weary glider however could not handle the extra pressure and around noon local time, Challengers aft leak detect went off again causing the glider to surface.

Challenger then sat at the surface while we again went through the process of pulling the more in depth files via satellite phone.  While at the surface, Challenger once again fell victim to the intensive currents in our area and got knocked around essentially being pushed in a circle.

After the files were pulled, Challenger’s way point was moved back to Sao Miguel where we will most likely recover from within the next few days.

Currently we are about an 8 hr trip from Sao Miguel out to where the glider is.  To try and counter the strong Northerly currents we are now diving to 300m over the past few hours.  So far there hasn’t been any aborts but hopefully this will be safe enough to get back for a recovery.

We will be keeping a keen eye on the weather and shipping traffic over the next days as Challenger limps back to shore.

At this moment, it looks like waves in the area are up around 5m which is far from ideal for a recovery mission, but this glider needs help and we are going to do our best to get it safe.

Lauren Cooney, Antonio Ramos, & Nilsen Strandskov

Hey All,

Just wanted to give everyone a quick update on Challenger’s situation.

We are still limping along, diving to only half our normal inflection point (500m).  There has been no official word yet on whether or not we will be pulling the glider out of the water, but the way point has been set to Sao Miguel and Challenger is continuing on his way to port.  Over the past day he has been closing in on the Azores and is now 160km from port.

Finally looking at the surface currents, we are on the outer edge of the cold core eddy to our east so over the next day or so we may begin to see currents pushing us to the North.

Lauren Cooney, Antonio Ramos, & Nilsen Strandskov

Hey All,

While for everyone else this merely an hour longer due to the clocks changing, it has felt like an eternity for the team working on the Challenger mission.  At 7:05 this morning, Challenger came to the surface to call in an abort saying there was a problem…

The report it sent back stated the glider had detected a leak in its aft compartment while at depth.  Challenger then sat on the surface for hours as the panicked team moved into action and began downloading all files over satellite connection so we could piece together the entire story and figure out what was going on.

Lauren and Chris (TWR) combed through the data after and concluded that on the second down cast of this mornings segment, the glider detected a leak at 940m below the surface (leak is defined as a voltage below 2.0V through the leak detect mechanism).  The resolution for the sensor was not too great as it was not being recorded frequently so we do not know when exactly the voltage dropped, but by the time the glider returned to the surface the voltage was back up to above 2.5V.  Dave Aragon of Rutgers also looked at the data to see if he could see anything from a different point of view but didn’t see anything suspicious.

Since the data analysis, there have been a number of test missions to see how the glider flies.  As of 11pm we have run test missions diving to 30m, 150m, and 500m as we ‘test the waters’ and all have been successful.

Now we must figure out what to do with this glider.  It really comes down to either continuing on the epic journey and putting this scare behind us, or taking the glider back to the Azores and pulling it out of the water for a servicing.  In the scenario where we go and pull the glider out of the water, a ship would leave from Ponta Delgada on the Island of Sao Miguel, Azores.  From Challenger’s current position, it would be about a 175 km trip out to the glider which would take about 9-10 hours making it a very long day going out and back to pick it up.

If we do pull it out of the water for servicing, Challenger still stands with the record as the 3rd longest flight in Rutgers History, which it will undoubtedly get more chances to break as it will still have at least 3 more stints of the Challenger mission: Sao Miguel to La Gomera, Canary Islands (stint 2, blue), La Gomera to Cape Verde (stint 3, green), and Cape Verde to the Americas (stint 4, magenta).  If we end up returning to the Azores, it only adds to the history of ocean exploration as these islands have been a crucial stopping point for countless voyages through the ages on long journeys.

We will update tomorrow on how the glider is doing and any decisions made.

Lauren Cooney, Antonio Ramos & Nilsen Strandskov

Hey guys,

Just a quick update on Challenger’s progress.

Yesterday afternoon we moved the way point to the South East so that we could begin making progress towards the Canaries.

Another deciding factor behind the movement of the way point was to avoid becoming caught in the bottom edge of the large warm core eddy to the North East of our position.  This would cause us to slow even more and possibly even drag us to the North.  Now, although we may be fighting the outermost edge of the cold eddy, the currents are weaker than the ones we would have encountered, and there is the possibility of a strong south flowing jet that will help us on our way.

Lauren Cooney, Antonio Ramos & Nilsen Strandskov

Hey All,

While the words ‘Trick or Treat’ can be heard all over the country this evening, Challenger seems to be encountering some tricks of his own.  Looking at the currents at depth provided by Antonio, it seems that although at the surface the waters are flowing in a nice south easterly direction, at depth the flow is in the opposite direction.  In the first figure below we have vectors showing the direction of the currents.  At 300, 500 and 700m the currents in Challengers immediate location are to the North fighting us.  Because of this we are only covering about 6km per surfacing.

The next figure also supports this theory as we go deeper in the water column, the northern flux intensifies.

For right now, the consensus is to just keep chugging away with the current with the current correction setting on so we don’t drift to the north or over shoot a way point change which could land us in treacherous bathymetry.

Finally, as we prepare for the final haul towards the Canaries, we have started to discuss where we would like to make port.

One place which caught our eye is the island of La Gomera.  This Island has a few pretty cool features that are symbolic for this effort.  First, is the location.  Gomera is pretty far to the West of the archipelago which would make the trip out to recover the glider much easier and the distance we must fly shorter.  There is also less shipping traffic in that area compared to some of the other islands (which is always a plus).  Another appealing point is the name ‘Gomera.’  For those of you who have been following us from the beginning, the true name for this glider is Silbo (the glider was christened Challenger 1 to signify it is the first attempt at the Challenger mission).  The name Silbo comes from the name of the whistling language ‘Silbo Gomero’ which was used to communicate through the extensive valleys on the island of Gomera.  Lastly, there is historical significance that ties back to the landing of the Ru27 mission.  When we took Scarlet across the Atlantic, we landed in the cozy little village of Baiona, Spain, where the Pinta made port in 1493 when Columbus returned from the first voyage to America.  Antonio pointed out today that San Sebastián, the capitol and main port of Gomera was the last stop Columbus made before starting that historic voyage in 1492.  This will be some thing to keep in mind over the next few months as Challenger gets closer to the Canaries.

Happy Halloween Everyone!

Lauren Cooney, Antonio Ramos & Nilsen Strandskov

Hey All!

Today we have a very special post: We have the first pictures from the inspection done last week off of the Azores!  But first, Challenger is still flying due east thanks to the navigational help of the current correction keeping us on a b-line to the way point.  It looks like we are still about 60 km from being able to make an adjustment to the way point that will allow us to get around the dangerous bathymetry to the south and south east of us.

Now to the inspection.

Early Thursday (10/27), the Portuguese Navy vessel shown below set sail from the port of Praia da Vitoria to sail out to the position of the glider to do an ocular inspection.

On board there were scientists from our partners at Teledyne, the Azores and the Canaries.  From left to right: Santos Martinho (Hidrográfico Marinha-Portugal), Eduardo Manuel Vieira de Brito (Centro de Estudos do Clima, Meteorologia e Mudanças Globais, CMMG), Christopher Decollibus (Teledyne), Francisco (Centro de Estudos do Clima, Meteorologia e Mudanças Globais, CMMG), Ángela de Manzanos (Plataforma Oceanica de Canarias, Plocan), Francisco.

The seas were pretty rough, but we had people willing to go out in a zodiac to give this brave glider a proper ocular inspection.

Chris DeCollibus described the glider as being so clean it could have just come off the inspection line.  This is great news as we had run into a number of problems with gliders being out for as long as Challenger has.  With the RU 27 mission, we saw a large amount of biological growth on the exterior of the glider that accounted for a significant degradation in velocity over time (seen in the plot below).

Plot by Dave Aragon of RU27 Vertical Velocity & Pitch. Before Servicing in the Azores, 27's speed decayed at 3.25 cm/s due to biological growth

What caused this reduction in speed is the presence of the goose neck barnacles.  When these organisms feed, they spread out their fan like appendages that allow for their filter feeding.  When these fans are spread out when the stalk of the barnacle is on a glider, this can cause a large amount of drag which leads to a massive reduction in speed.

Goose neck Barnacles: The main culprit in the degradation of glider velocity

What makes it even more remarkable about the fact that Challenger has withstood any biological growth over the past 130 days at sea is that there is no anti-bio fouling paint.  What we believe has allowed Challenger to survive unscathed is the immense difference in temperature and preasure the glider sees everytime it goes from the surface to depth

After concluding that the glider was still in exquisite shape, he was sent back on his way to finish his mission.

With the way the surface currents have a flow due south while the glider is recording currents flowing in a 180˚ difference due north, it is best to keep the way point where it is for now and allow the current correction setting to continue doing an excellent job flying us straight to the east past the numerous sea mounts in the area (seen in the previous post).

Once we get out to the east past Sao Miguel and Santa Maria, we can move the way point potentially to about 36 N 21 W (depending on what the currents are doing) to then allow us to cut down to the south on our way to the finish line.

Lauren Cooney, Antonio Ramos & Nilsen Strandskov

Hey all,

So as we shuffle through the remnants of a record breaking snow storm and get our costumes ready for the mystical holiday of Halloween, Challenger continues on his epic journey.

After a successful rendezvous mission off the coast of Terceira, where a team of scientists went out to do an ocular inspection of our inspirational little robot, we found that after over 126 days at sea there was no significant biological growth on the exterior that would be detrimental to the remainder of the mission.  This is truly incredible as during the 27 Trans Atlantic mission there was a significant amount of growth that slowed us down to the status of a drifter.

Now that we are on our way out of the archipelago, the next thing we need to keep an eye on is the bathymetry and currents to make sure we can cut back to the east so we can get back into consistently deep water on our way to the Canary Islands.  Looking at geomapapp, it looks like if we continue in our eastward fashion until about 24˚W we should be able to keep from running aground.

Once we get around these obstacles, it looks like we may be free of any restrictions of how deep we can fly

Next, looking at the currents, there is the Azores Current which has a general East-SouthEast flow from the Azores right towards the Canary Islands.  Although we may have to fight it a bit to continue east until we are away from the shallower depths, this flow will hopefully aid us on the final leg of this mission and help up conserve some battery.

The Azores current is the tail end of the Gulf stream that breaks off to the south as massive current runs into the European and African continents.

Now zooming into the immediate area of the glider, we are experiencing a storm that has to have pushed us up into the high 40’s (I have lost count).

This has started to notably shift the direction of the currents from North West to the North and now back towards the west.

Looking at the surface currents, we are just to the west of a few warm core eddies that are causing currents that may drag us up to the North East as we move out East past the bad bathymetry.  Once we get out to about where those eddies are positioned, we will move the way point south and turn our nose towards the Canary Islands.

Finally the Sea Surface Temperature data from ULPGC looks amazing as we are on the cusp of another strong band of temperature gradient as we get closer to the tropical waters of the more southern region of the North Atlantic.

We will post again soon with further updates

As always Force Wind Sea and Honor

Nilsen & Antonio