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.

Force Wind Sea & Honor

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

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.

Force Wind Sea & Honor

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

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.

HYCOM Forecast 8/19/2016

OSCAR Current pastcast 8/17/2016

RTOFS Forecast 8/19/2016

Copernicus Forecast 8/19/2016

Force Wind Sea & Honor

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

HYCOM Forecast July 20

RTOFS Forecast July 20

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

Force Wind Sea & Honor

90 days into its mission, Silbo is continuing to fly like a champ, averaging 37km/day!

Looking at the models, Copernicus continues to match the currents reported by the glider nearly perfectly, showing a flow to the northwest as we enter the western edge of a small warm eddy while the RTOFS and HYCOM models show a flow to the south east.

Copernicus forecast 7/12/2016

HYCOM Forecast 7/12/2016

RTOFS forecast 7/12/2016

To further take advantage of the currents reported by Copernicus and verified by the glider’s calculations, at the next surfacing, Silbo will pick up a new way point which was set 100km north of the current point, at 44˚30N 37˚W

We hope this way point will allow us to take the northern route outlined in the image above as we try and make our way further to the North East towards Europe and the United Kingdom.

Force Wind Sea & Honor

Since last week, Silbo has rounded the center of the large eddy we were navigating and has serpentined along with the current up to the Northern branch of the Gulf Stream.

Silbos track on the North Atlantic Crossing

To make things even better as Silbo continues to fly over 40km / day, the roadmaps we are using for navigation all seem to be agreeing quite well as shown in the following images of the Copernicus, HYCOM and RTOFS model outputs respectively.

Copernicus June 21

HYCOM June 21

RTOFS June 21

For now, as Silbo starts heading back in to the meat of the Gulf Stream, we will continue to fly to the North East, keeping the way point where it is throughout the remainder of the week.   As the stream carries the glider to the North, we will eventually want to cut across the branch of the stream as we will then need to continue a North East trajectory as we aim for northern Europe.

Force Wind Sea & Honor

Now 60 days into its crossing of the North Atlantic, Silbo has made it further than the eastern shores of Newfoundland and is now due south of Greenland.

As we continue to follow the gulf stream out past the reaches of the continental shelf, the jet begins to diverge revealing paths to the north and south which are nicely depicted in our ocean forecasts for the day

RTOFS June 13

OSCAR June 11

HYCOM June 13

Copernicus June 13

With this afternoon’s surfacing we moved the way point to the north east as we aim to catch the the jet the jet that shoots off to the north east as we try to make our way towards Northern Europe.

Force Wind Sea & Honor

With Silbo closing in on the center of the next main eddy, the team has started looking further in to whether to go north to Iceland/Ireland/Europe or South to the Canaries.

The general consensus is that we want to continue to the north towards the United Kingdom and so as the glider approaches the eddy, we will hold the current way point until passing to the other side of the core where we will then move the way point to 41˚42N 50˚00W and potentially switch on the thruster to make sure we exit to the north eastern sector of the eddy.

Copernicus June 10

Force Wind Sea & Honor

As Silbo continues to surf the Gulf Stream, the glider is looking like its put the pedal to the metal as the km/day seems to climb further with each passing day.   The latest numbers are showing the glider reaching speeds of .72m/s or over 60 km/day!

Today the glider has reached the top of the warm core eddy and will over the next days follow its flow as the gulf stream then meanders south around a counter clockwise spinning cold core eddy.

Copernicus June 8th

For now the way point seems to be doing well, although with the speeds we are seeing we will need to push the way point further out over the next couple of days

Force Wind Sea & Honor

Since moving the way point to the south east in order to keep the gliders progress in to the Gulf Stream, Silbo has taken off accelerating from 15 to over 50 km/day!

When the way point was set a week ago, the current had shifted to the point of being due west as Silbo made his way through the eddy solar system discussed in the previous post.  With the change in heading, Silbo ended up making a small loop before catching the eastward flow of the Gulf Stream again propelling the glider forward at the new break neck speeds.

Looking to the various road maps, this week Copernicus and OSCAR are mirroring the glider reported currents.

Copernicus June 3rd

OSCAR June 3rd

In today’s ROTFS and HYCOM visualizations, it is showing the glider has left the branch of the gulf stream and should be seeing the effects of the northern edge of a cold core eddy.

RTOFS June 3rd

HYCOM June 3rd

Force Wind Sea & Honor