Category: silbo (Page 5 of 22)

Hey All,

As our gliders continue to push onwards, both has slowed down a little as we encounter some less than favorable currents.

From the start of this month through this week, Challenger has run into an eddy that developed as we approached leaving us little time to react, resulting in us flying our glider up the eastern side of a clockwise rotating eddy:

In the animation above, we can see how as the glider approached the area in question as there appeared to be currents that flowed up to the north west.  Then as we got closer to the area, the currents shifted and by the time we were about even with the center of the small eddy, the currents then accurately showed the rotation that was plaguing our progress.

Although this causes some frustation as the pilot when we lost some of our speed, instances such as this do leave us with a sense of accomplishment as we can see the data from our gliders being reflected in the models that our data is being plugged in to.

We can also see the fight with this eddy reflected in the velocity data above.  As we approached the eddy, we can see how our velocity continued to plummet until just recently as we rounded the edge of the eddy and now we seem to be increasing ever so slightly.  Hopefully we will be able to sustain this increase in the coming days and build up some more speed.

Over the next day, we will also be keeping an eye on the bathymetry around both Challenger and Silbo, asa they both are in the midst of obstacles:

Challenger is crossing the last of the sea mounts that are associated with the chain we have crossed a number of times now as we put distance between ourselves and the African Coast.

Silbo on the other hand is about to cross the Mid Atlantic Ridge for the second time, the firs being back in June of 2011 when we deployed out of Iceland along the Mid Atlantic Ridge.

Both of these regions reach up less than 1000m in some regions but we have taken the necessary precautions to make sure we do not run aground.

Force Wind Sea & Honor

Hey All

This semester, I have made the leap transitioning to being a lecturer for the Ocean Observatories course that I took every semester under Scott Josh and Oscar for 4 years beginning with the fall semester of RU 17.  And in helping with the class, I have built a model comparison tool that takes the data from both Challenger and Silbo and compares it to the data provided to us by the ocean models we have utilized as our road maps.  These models not only provide us with the direction of the currents, but also have temperature and salinity.

One observation we have made now that we are tracking the comparisons, is that it seems that the models are underestimating the temperatures at depth; not fully capturing the temperature transfer at depth in the vertical direction.  This could potentially skew the results of forecasts made based off of this data for such cases as climate change and other cases dependent on similar data.  To aid with this, the data from Silbo and Challenger is now being fed back into the models to hopefully aid in the accuracy as we provide data points that were not previously available.

A few days ago, Silbo suffered from another mysterious reset at depth, followed by an increase in movement by the pitch battery- with little trace of why this is occurring   After analyzing the data, the movement of the battery is still not completely known, however our friends up at TWR have been able to lock it down and reduce the movement.  This has allowed Silbo’s spike in energy usage to level off returning the estimate on how much energy remains into next year; well past our estimated date of arrival in the Caribbean in mid summer.

Challenger is continuing to fly well, however, we seem to have found a small eddy that is rotating against our favor, effectively slowing us down.  Over the next couple days, we will continue to explore this anomaly and make a decision as to where to go from here.

Force Wind Sea & Honor

Hey All

So almost simultaneously this weekend, our two gliders, Challenger and Silbo, have each crossed major milestones for our Very Important Glider Club: Challenger passed the 2000 km mark and Silbo the 4000!

As impressive as this is, Challenger’s numbers are even more so as she has gone half the distance that Silbo has done in a fraction of the time.

Both gliders are continuing to keep their speeds at respectable numbers as well.  Challenger, although we are seeing a decline in our velocity as we have found ourselves falling into what seems to be an unfavorable current, she is still above 20 km/day.

Silbo on the other hand, seems to be leveling out a bit just below 20 km/day.

Based on these numbers, if our two Global class gliders can maintain these speeds, we can expect Silbo to arrive in the Caribbean somewhere in the middle of July.

To the South, Challenger running 20+ km a day may carry us across to Brazil by the end of the year, leaving us with roughly 40 days of wiggle room on our battery power.

Force Wind Sea & Honor

Hey All,

So today in the Ocean Observatories course taught by Scott Glenn, Oscar Schofield and Josh Kohut, I proposed a question to the 70+ students in attendance: Where should we take Silbo and Challenger as we work our way across the Atlantic Basin?

Originally, our plan was to take the two gliders and create an X across the Atlantic, taking both gliders from pole to pole as Silbo flew from Iceland to Antarctica, and Ru29 from South Africa to Svalbard.  But now, we have altered Silbo’s path to fly towards Barbados as we were making little to no progress as we tried to fight our way to Brazil.  No knowing of the difficulties to get south, we began to reanalyze where we want to go with these gliders.

If we fly the gyre, it would follow the path shown above, continuing across the Atlantic towards Barbados, then north towards Rutgers and TWR, then west to Ireland and finally onwards north to Svalbard.

If we take this path, Challengers path will also become altered, restricting us to the South Atlantic Gyre:

The will then consist of our current flight across to Brazil, then flying south the Falkland Islands, across the Drake to Palmer Station, and then following the Antarctic Circumpolar Current either back to South Africa, or possibly push out limits and try for western Australia.

After proposing these paths to the class, all but one student said we should fly the gyres.  The one that stood up to say we should follow the original path of the X followed up his suggestion with the argument that it would interesting to compare the data from the two gliders in an attempt to look for changes in the water column.

These discussions will have quite a lot of follow up in the weeks to come.

Force Wind Sea & Honor

Hey All

1. Bathymetry Google Earth Overlay created in GeoMapApp shows the locations of seamounts that could be an abrupt end for Challenger

With the treacherous bathymetry associated with the seamounts of the Walvis Ridge falling away from us, we moved the way point to the north west. There, we should fight the eastern drift a little better as we cross the eastern flux associated with the warm eddy we are traversing.

2. Pinzon 4D is a four dimensional representation of the currents from surface to 1000m over a created by our partners at U. Las Palmas Gran Canaria

By turning to the west, we will also reduce the noise in our heading data caused by an error in our compass.  From here, we will continue to fly to the North North-West, weaving a path through the eddies and currents as Challenger makes way towards St. Helena. Then, we will continue pushing north towards the powerful equatorial current that flows to the west which will be the key to a successful recovery in Brazil before the end of the year.

3. Heading Statistics for RU 29: Due to a compass error, we have issues flying north. This is seen as the std dev increases between 3/11 and 3/18 when the way point was to the north versus to the west during 3/3-3/11 and 3/18 onwards

4. The Real Time Ocean Forecast System shows the surface currents that we will use for navigation from South Africa to Brazil

With our new plan to fly Silbo to the Caribbean for a tune up before pushing on to Brazil, the first step was to move the way point to the north west.

5. Silbo’s progress thus far on the crossing of the southern edge of the North Atlantic Gyre

However, as we made this adjustment, Silbo began to feel the influence of the large cold core eddy to our west.  This resulted in a less favorable increase in our velocity than we expected as we try to reduce the fighting of the strong northward flux that has slowed our progress over the past five months.

6. The break down of the currents seen by Silbo. Cyan is surface drift velocity, magenta is depth average current, red is heading and green is velocity through the water

Over the next day or so, relying on the forecast holding true, we should begin to see a more north western flow as we begin to round the north eastern edge of this counter clockwise rotating eddy.  From there, we hope to catch the current represented by the long winding vectors running to the west shown in bottom left image above.

7. The RTOFS Sea Surface Height and Surface Current forecast for 3/22/2013

With todays projections of distance versus remaining battery power, Silbo should be able to reach the sunny shores of Barbados, and after some work, continue on to Southern Brazil and finally Palmer Station Antarctica.

8. Silbo’s Proposed Mission from Iceland t Antarctica June 2011 – 2014 (expected)

Force Wind Sea & Honor

As I mentioned in yesterday’s post, after a discussion with our team last week, Silbo is now headed towards the Caribbean. By making this move, we are hoping that we will be able to take advantage of the northern flux we have been fighting for months now, along with the force of the southern edge of the north atlantic gyre.

For the moment, Silbo is just slowly gaining speed, as it seems that as we moved the way point, we entered the influence of a large cold core eddy, thus producing a current that continues to push silbo 90˚ to where we are trying to fly:

However as Silbo continues to pursue the caribbean way point to our west, we should begin to feel the north west current.

To the south, today we gave Challenger a new way point.  Now that we are free of the treacherous bathymetry we moved the way point far out to the North West as begin to approach the island of St. Helena.

We are also looking forward to seeing the results of what the steering looks like.  Below is a plot of the heading error standard deviation.  Within the past few weeks, we can see that the std dev has rose from about 7 to 12.  This is due to the error in our compass that appears when we face to the north.  By turning more to the west, this should reduce the prominence of this erros allowing Challenger to fly better. We will update again soon with the progress of our gliders as they trek across the Atlantic

Force Wind Sea & Honor

Hey All

As everyone enjoys an exciting St. Patricks Day weekend, Silbo has turned to the west, now setting his sights (for now) on the Caribbean.  With the strong partnerships we have formed there over the years, combined with the less than favorable currents we have been caught in, we will push the limits of this little guy yet again as we extend the distance of his excursion across the Atlantic in order to reduce the time strain.

With the first segment following the new way point we say about an 18% increase in the distance covered, and we hope that number continues to increase as we try and take more advantage of the northern flux that has plagued us for so long.

However down in the South Atlantic, Challenger is doing great as she continues to surf the tail current that makes up our north bound free way.

Force Wind Sea & Honor

Hey All

As the week goes on, Challenger continues to fly to the north amongst the mountains.  The way point, now due north is allowing us safe passage through the valleys of the sea mount-ain range that spans over 3000 km from Gough, Inaccessible, and Nightingale Islands in the South Atlantic, to the western coast of Namibia.

As we pursue this way point, we will progress north over the course of the upcoming weeks, before we begin to opt for lateral movement as we head west towards the islands of St. Helena and Ascension and set our sights on the equatorial current that Challenger will surf towards the norther shores of Brazil.

To the North, we are still in discussion on which direction we will take Silbo.  But looking to the RTOFS current velocities, it looks like if we want to begin making better progress, we should move the way point to the north and fly to the northern edge of the cold eddy.

As Silbo makes his way north around that eddy, it will buy us time as we decide where we will fly to to bring him back to tip top shape.

Force Wind Sea & Honor

Hey All!

As the title suggests, we are blasting Led Zeppelin tonight as Challenger flies north through the numerous sea mounts that stretch up into shallows.  Dave was able to create a very helpful kmz overlay highlighting the problematic areas that lie ahead.  With the location of the way point, and our proximity to the warm eddy to our north, it looks like we are set up nearly perfectly to to curl through the trouble areas as we continue our way to the north.

And to the North, Silbo is continuing to push along, making about 12 km progress per day.

As I had mentioned earlier, for the past week now, there has been a lot of discussion on where we should fly Silbo, as making our way south to the horn of Brazil is seeming to more difficult than we originally thought.  We ran some numbers over the past few days, and battery wise, we have roughly 290 days left.  If we were to continue to try and fly south returning to a progress of 6 km/ day and taking into account the degradation of our velocity due to growth on our hulls, we most likely would fall short of our goal.  However, if we were to our way point to the north west, we could make good progress as we take advantage of the current we have been fighting for months on end and shift our finish line to either the northern edge of Brazil, or, the lower Antilles such as Barbados.  These options are well within reach as we could potentially see speeds upwards of 20 km / day allowing us to arrive in mid to late July.

This discussion will continue as we arrive at a decision of where the most ideal place would be for a cleaning and rebattery for Silbo.

Force Wind Sea & Honor

Hey All!

Over the past week, our gliders have continued to push on wards as they make their way across the Atlantic Basins.

To the south, Challenger has been making some inspiring progress as she has flown nearly 200 km as she entered the southern end of the freeway I have mentioned in recent posts.

Yesterday, we issued Challenger a new way point, moving it from the north west to nearly due north, that way we can surf the warm core eddy that is dead ahead. The placement of the way point, we hope will allow us to keep us from being pushed too far to the east by the flux created by the eddy, effectively avoiding getting too close to the near by EEZ.

Another obstacle we must keep in mind is the mountain range that lies ahead.  At some points, these sea mounts actually reach from the dark depths of the Atlantic to nearly 200 m from the surface!  Because of this, we will be switching on the altimeter that way if we come near these shallow points, we will safely inflect before running aground.  The new way point however should steer us clear of any trouble areas.

Antonio’s 3D visualization of the Hycom forecast model also shows that the currents up until tomorrow will continue to to hold, providing confidence in our decision of the way point.

To our north, Silbo is still ‘turtling’ (as Antonio described) his away across the North Atlantic.  It has been over a month now that we have been pursuing the large warm core eddy to the south west and over 4 months since we have had evidence of a favorable current.

Taking this into account, there has been talk amongst our team of adjusting our path and veering  away from Brazil for the moment.  The most promising choice at the moment, is to move the way point to the north west, taking advantage of the current we have been fighting for 1/3 of the past year and heading towards Barbados and St. Thomas.  Here, Silbo can get a nice rest, a good cleaning, fresh anti biofouling coatings, and a new set of batteries, thus giving Silbo a fighting chance as we push to get around the horn and to the South towards Rio.  There will be more talk of this throughout the week and we will make sure to keep everyone posted.

Force Wind Sea & Honor