Archive for June 29th, 2011

Aiming East to go South

Wednesday, June 29th, 2011

Hey all,

So today we we continued our global collaboration to choose our path for Challenger 1.  In order to conserve battery power, we have now turned off our altimeter.  This will causes us to use less battery power which is crucial while we are still in the first days of the mission flying in frigid Arctic water.  However, we are now flying solely off of bathymetry maps.  Luckily, between U. Las Palmas Gran Canaria and Rutgers, we have found two different models showing the depth of the sea floor in the area we are flying that correlate very well and so have boosted our confidence allowing us to do away with the altimeter at least for now.

 

Bathymetry Map provided by Antonio

 

 

In the above images, the top being from Antonio and University of Las Palmas GC and the bottom two being from Rutgers, we can see that we should be safe of running aground if we stay in the channel between the Mid-Atlantic Ridge and the rise off of Europe.  Zooming in, it looks like we will have to avoid the line going diagonal south in the image below (starting from about 24) if we want to continue safely flying to 1000m without our altimeter on.

 

So after studying the bottom, now we must take into account where the water is going and how the glider is flying.  After moving the waypoint yesterday to try and get us moving further south, our speed dropped from between 1.2-1.35 km/hr to .87km/hr.  We seem to have hit a small eddy whose currents had started sweeping us west.

Antonio provided another similar model that showed that we are in the midst of a few cold eddies that if we maneuver around correctly, we will be able to shoot ourselves further south and find a few more currents that will aid us along the way.

Sea Surface Height and Currents Provided by Antonio

Another thing which may prove piloting this glider to be a little bit tricky, is we have some reason to believe that Challenger 1's compass may be slightly off and could possibly be over estimating the power of the currents resulting in a heading error.  On Monday, back before the waypoint was changed, we calculated that our heading was off by about 40 degrees, which from previous experience could be explained by the compass and an over estimation of currents.  Today, we recalculated after finding the loss of speed, and found that today we were off by a little under 50 degrees which again could be a result of the currents that we were now fighting.  Taking this into account along with the eddies we are now trying to navigate, we will have to move our waypoint further east to effectively get Challenger 1 on its way south.  During the next surfacing we will give the new point to the south east and see how we fly.

Finally, yesterday evening back home in the COOL room, visitors from The Ocean Observatories Initiative or OOI, were given a tour of our facilities by Scott.  Our visitors are some of the leading names in modern day Oceanography, and through OOI are revolutionizing the way we study the global ocean.

 

 

-Nilsen