Hey all,
Since he has been sent on his way, Silbo has been making excellent progress as he sails towards the end of the first leg of the Challenger Mission. Over the weekend, he broke new ground as he is now less than 1000km from the finish line! As the crow flies, he is 950 km from the gorgeous shores of the Canary Islands.
Figure 1. Estimated Remaining Distance for the first leg of the Challenger Mission
Looking into the bathymetry of this region of the Atlantic, Silbo is now seemingly free of any dangerous terrain which will allow us to continually fly deep and therefore conserving energy.
Figure 2. Bathymetry from Azores to Canaries
Energy conservation will be crucial over the upcoming weeks. After the very energy consuming leaks and recovery opperations we have a few weeks ago, we have done an energy consumption analysis (courteous of Ruben’s plot below). It looks like we have enough power to last us until the first week of February. This is slightly concerning because if we are able to maintain an average velocity of 1km/hr, that leaves us with between 50-60 days from the Canaries with a recovery date around January 20th. So if everything works out in our favor, we could make it. But if we have learned one thing working on long duration glider missions is that we must be prepared for the unthinkable because anything can happen.
Figure 3. Esitmate end date of the mission based off of remaining battery life by Ruben Marrero
So we have two options: cross our fingers and hope that through precise path planning we can push our way through to the Canaries, or we stop at the Island of Madeira (Portugal) where our friends at PLOCAN have a planned mooring deployment and facilities where Silbo can get checked out and new re-batteried.
Figure 4. Sea Surface Height and Surface Currents (ULPGC)
Looking at Figures 4 & 5 of two different plots of Sea Surface Height and Surface Currents, we see that we are in the midst of a cold core eddy (counter clockwise rotation).
Figure 5. Sea Surface Height and Surface Currents
However, looking at Figures 6, 7, 8and 9, there actually appears to be a staircase in the currents that goes from our most recent location to both Madeira and The Canaries.
Figure 6. Stairway like path to Madeira and The Canaries
Figure 7. Currents and North South components for Surface waters and at 200m
If we inspect at depth, we can see that a similar pattern can be found in the currents reaching to 1000m below the surface.
Figure 8. Currents and North South Components for 400m and 600m
Figure 9. Currents and North South Components for 800m and 1000m
If we continue to find a similar path over the next two months, this staircase may be very useful in reaching our destination.
Figure 10. Sea Surface Temperature satellite imagery from ULPGC for 11/28/11
Looking at the Sea Surface Temperature in Figure 10, we are now about half way through the band of blue and almost to the warmer waters, designated in green, where we will be for the last few hundred kilometers of the mission a we close in on the Canaries. It will be interesting to see what the biological growth will be like as Silbo passes through the green and when he continues his journey past the Canaries in the tropical waters of the North Atlantic.
Figure 11. Salinity at depths of 600m, 700m, 800m, and 900m
Finally, Antonio pointed out that we are now pretty deep into the ‘tongue’ of the salty Mediterranean waters. As we can see in Figure 11, starting at about 600m subsurface, we start to encounter some very salty water. As we get closer to the West coast of Europe we see that the levels increase even further which may lead to a strong halocline between 700-1000m.
Hope everyone enjoyed their Holiday!
Force, Wind, Sea & Honor!
Lauren Cooney, Antonio Ramos, Oliver Ho, Lindsay Howell & Nilsen Strandskov