Tag: Nilsen Strandskov (Page 7 of 11)

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

Hey All,

Well the mission to go out and meet Challenger has been pushed back until early tomorrow, at about 6am Azores time/2am EST.  Until then, the way point has been shifted to the east where we will then be able to avoid the treacherous shallowing landscape leading to the doorstep of the Azores.

We wish our diverse team good luck on their mission tomorrow and Force Wind Sea and Honor to all

Nilsen & Antonio

Hey All!

In just a few hours now, the last of our team will be landing on the beautiful island of Terceira and conducting final preparations before leaving dock at 10:30am (6:30am EST) and will spend the day sailing out to the glider.  Unfortunately as of right now, Challenger is still just under 90 km from the port of Praia da Vitoria, but by the time they leave it will be closer to 70 km away.

While on the trek out to the glider, the ship will also deploy two new buoys to collect data while drifting with the currents, so it will be a long day for everyone.

We will keep everyone posted on the progression of the inspection

Force Wind Sea & Honor

Nilsen & Antonio

Hey All!

Challenger is continuing to chug along as it gets closer to the Azores.  By morning, this brave glider will have acomplished yet another incredible feet, flying over 3000km since deployment just 124 days ago!  After moving the way point to the west late last week, Challenger continued past the Sedlo Seamounts, and is now on his way back east towards Terceira.

Challenger is now also less than 130 km from the tropical shores of the Azores.  Wednesday the 26, a team of scientists from the Canary Islands, the Azores, and from Teledyne Webb will set sail from the port of Praia da Vitoria and meet up with the glider.  There, it will be inspected to see if there is any significant biological growth on the exterior.  There will also be a number of files pulled off the hard drive to make more room for the final portion of the journey to the Canary Islands.

ULPGC Sea Surface Height & Currents

HYCOM Sea Surface Heights & Currents

As we close in on our rendezvous location, there is a little discrepancy between the models forecasting what the conditions are like.  The first figure shows the ULPGC data showing strong currents that flow right towards our way point off the eastern coast of Terceira.  The second figure is from HYCOM, showing quite a mess on the road ahead.  As of right now, Challenger has been seeing a correlation shown by the ULPGC data, and if this holds true by Wednesday morning we should be within 80km of the port.

Finally, our friends at ULPGC provided us with a weather forecast for the date we plan on being out on the boat.  On the 26, it looks like there will be waves reaching up to 3m with winds potentially reaching 25 knots.  This will cause the swells to have a period of about 9 seconds.

We’ll keep everyone posted on the inspection!

Nilsen & Antonio

Hey All,

So Challenger is continuing to inch ever closer to the Azores (<250km) as we begin preparing for next weeks inspection off the coast of Terceira.  However this also means we are getting closer to the Sedlo Seamounts (<60km).

These seamounts as we had mentioned last week may reach up to nearly 500m from the surface, which poses a threat to our brave little droid.

To make it worse, three models of sea surface height with currents confirm there is a large warm eddy just to our west that could be strong enough to pull us right into range of the seamounts which would be detrimental to our flight.

ULPGC data for SSH and Currents

HYCOM SSH and Currents

Model from Antonio at ULPGC

Since late last week now, we have been flying with the current correction on try and keep us as close to the path to Terceira as possible so hopefully that will aid us in avoiding being dragged too far west towards the seamounts.  Also we may move the waypoint further east a bit to try and point us more away from the obstacle and towards the rendezvous point for late next week.  We have also moved the way point east to 25.5 to try and steer ourselves away.

As always Force Wind Sea & Honor

Nilsen, Antonio & Oliver

Hey All!

So Challenger 1 is continuing on his way towards Terciera making great progress as the past three surfacings have each carried us over 10km.  This is due to the presence of currents finally moving to the south and aiding us instead of causing resistance.  In order to try and take the most advantage of these currents while they are helping us, we moved the way point further to the west to try and decrease the angle we were flying relative to currents to a minimum.

Sea Surface Height and Surface Currents from ULPGC

Looking at the data from University of Las Palmas Gran Canaria, at the surface the currents are moving to the North as we are on the western side of a cold eddy.  However, looking at the water’s velocity at depth, we are finding much more favorable currents.

Currents at 300m depth

By abiding by our new protocol of flying 25m-1000m instead of (0-1000m), we are not only avoiding potentially being struck by a boat, but also the upper 25m of those Northern Currents.

Unfortunately, it looks like we may not have these currents for much longer.

Since October 8th, it seems the currents have been following a large inertial oscillation where they have gone in a counter clock wise rotation from north 180˙ to the south where we were this morning, and now showing evidence that it is moving westward and potentially back to the north by Friday.  If this happens, we may run into yet another wall of currents.

This posses a problem energy wise, as our batteries continue to get drained at the same rate (or even greater) as when we cover a lot of ground.  After a little discussion of this, Lauren Cooney presented us with a plot showing that when we are flying into a head current (similar situation to what we saw last week) the estimated distance we have enough power to cover is cut down to about 2500km.  However looking at today with the currents behind us, our potential remaining distance is up to about 4000km.  So distance wise, it really comes down to how forgiving the currents will be to us.

Finally just checking out the energy plot made by our friend from PLOCAN, Ruben Marerro Gomez it is looking like we should have enough energy to sustain us through the beginning of February.

Now making an estimate of our path from our current location to just north of Terciera and over to the Canaries it looks like we should have enough energy to make it.  We are just about 1600km from our final destination and have used about 343 of our estimated 700 Amp-hr.

Check back for another update soon!

Nilsen Strandskov, Antonio Ramos, and Lauren Cooney

Hey All!

Sorry for the gap in the updates but we bogged down a bit by a few nuances called exams.  But anyway here is a recap of what our brave little droid has done over the past week.

First off, Challenger 1 has now gone 2,600km in just over 109 days, making its mission the 3rd longest of the Rutgers Fleet!

He also has a great view to his East as by morning, he will be crossing the border from Norther Spain to be parallel with Portugal.

Finally, Challenger is just about 400km from the estimated rendezvous point just north of the island of Terciera where the watersare still close to 1000m deep so that we can continue flying efficiently.  Here, an ocular  inspection will take place so we can get an idea of how much biology has grown so we can see the effects of consistently diving deep.  The ship that will be used is from the Portuguese Navy and a picture is below:

Over the past week, there have been a number of brief way point changes that have occurred.  Trying to line the glider up to fly a path where we could pull off getting close to the Azores for the inspection turned out to be the equivalent of threading a needle.

Towards the end of last week (oct 8th), we had been flying into a bit of a head current that cut our speed down a bit.  To get out of this, we gradually moved our way point three times to try and get around to more advantageous waters

Although it was slow moving and a bit boring to try and fight these currents, our models produced some really great looking imagery for our road maps.  Below find the map of Sea Surface Temperature from ULPGC

As the weekend continued, by the 9th, the currents had shifted from going North, to North West, West and finally to our south west.  When we saw the currents follow this oscillation, we decided to move the way point from our east back to the west to try and take advantage of these currents.

With the movement of the way point, we began seeing good progress yet again, however the currents began shifting back up to the north again.  To avoid these, we decided to incorporate our new flight protocol of flying below these pesky currents.  We flew 3 segments with our inflection depth set to keep Challenger between the depths of 200m-1000m until it is time to surface.

Another change made by Lauren was to the minimum allowable speed.  She pointed out that there is some sort of temperature anomaly about about 900m where we see the temperature increase back to about 9˚C.  The change in speed will prevent the glider from trying to make any unneeded changes to accommodate the change in density onset by the increase in temperature (the temperature shift can be seen on the last plot in the figure below).

After making these changes, we continued to make good progress as we now follow our way point and the currents a little back to the west.

We have also returned out inflection point closer to the surface, but not all the way there..

After seeing these images (each dot represents a ship of some sort), our hearts started pounding a bit harder.  As we have discovered in the past, gliders do not fair well against ships, and it looks like we have gotten pretty close now to areas that have pretty frequent shipping traffic that we will have to dodge on our way to our rendezvous point.  So we have left the inflection depth at 25m hoping that will keep us safe from any detrimental surface currents or collisions with ships.

That is all for now and we will have more updates soon!

Oliver Ho, Antonio Ramos, & Nilsen Strandskov

As we awake on this cloudy sunday morning, Challenger is in the midst of yet another storm.  But nothing in comparable magnitude to what is in store for Challenger in the upcoming weeks.

By the middle of next week it looks like the remnants of Tropical Storm Ophelia and Philippe will be reigning down on Challenger’s position.  The combination of these storms will undoubtedly cause some intense inertial oscillations for our little droid and it will be important to keep an eye on the intensity of these storms as they travel over the warmer waters of the North Atlantic.

The Jet Stream forecast even shows an intense meteorological oscillation to be in the vicinity for a week from today that may cause intense surface currents.

Nilsen & Antonio