Preliminary Path Planning

Hey all,

So this morning we were given a brand new mission:  Silbo, now to fly under the name of Challenger 1, will conduct the first leg of the Challenger mission, which is to have a fleet of gliders that circumnavigates the globe.  Challenger 1 is expecting to be deployed Thursday morning (June 23, 2011) out of Reykjavic, Iceland and work its way south over the next couple months to Las Palmas, Canary Islands, Spain.  In order to start preparing for this flight, we began looking at the hycom models of sea surface height with surface currents to try and get an idea of where we will have to steer this glider...

These over lays really show how difficult this mission may become.  In the map above, the black lines depict about where we want to keep Challenger 1 while on its mission as to keep it on the most direct rout possible to the Canaries, while staying far enough from main land Europe to avoid the heavy shipping lanes.

From these figures it seems starting out, the currents are going to pose a problem for us.  The Gulf Stream, which helped us so much during the 27 mission, now is our enemy.  Part of the tail end of this massive current peels off and goes north towards Iceland, meaning we have a number of currents going against us.

The following 4 links are gifs showing the water conditions south of Iceland that also show how tricky these waters will be.  All 4 depict a number of eddies that we will have to fly through.

Sea Surface Height

Sea Surface Temperature

Sea Surface Salinity

Currents

The figure below shows two possible paths that will put Challenger 1 against the least amount of resistance.

In the hycom model overlay seen above, we can see how we are really going to need to fight our way back and forth through the oncoming currents.  To add urgency to the matter, we are also in a race against the clock to conserve batteries.  Operating in cold water drains battery life faster than in warmer waters, so our need to get a move on will be priority.

However, we have a trump card.  Challenger 1 has the capabilities to dive to depths of about 1,200 meters (nearly 4,000 ft).  With our previous experiences of flying the two gliders, Drake and Cook, we know that if we fly deep enough it is possible to effectively fight unfavorable currents.  Keeping this in mind, we checked out the bathymetry of the region using geomapapp.  In the graph below, we have the bathymetry if we were to draw a straight line from Iceland to the Canaries, along with the map below where the red is shallower waters vs blue being deeper.

Luckily, we don't have to go too far to get to where the water is deep enough to really take advantage of the benefits of using a deep glider.  Some of these being that we can dive further to where the currents are not as persistent, and that because of the extended amount of time it takes for the deep glider to complete one undulation, the pump in the nose of the glider moves less conserving more battery.

That is all for now, and be sure to check for updates as Challenger 1 is expected to be launched early Thursday morning.

 

Nilsen & Oliver

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