Archive for October 23rd, 2009

Running downstream

Friday, October 23rd, 2009

 After running east with our head down to escape The Wall, we just turned Scarlet northeast at the 8 pm surfacing.  We have northeast currents along a northeast course. We'll run downstream until at least noon tomorrow.  To properly exit on the eastern side, we need to ride one of the outer rings of this eddy. The straight east course was running us a little too close to the center.  The worry is trying to fly due east out of the center - if you don't make it out in time, you risk spinning around for another lap.  The Wall already caused a delay, we don't need another.

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Back in the Race

Friday, October 23rd, 2009

Scarlet has broken free of The Wall and is now has a series of four 8-hour segments with currents to the north, in excellent agreement with the geostrophic currents derived from the satellite altimeters.  The Wall explored by Scarlet is still not resolved in the altimetric data, which for us defines the scales of resolution we can expect for the rest of this trip.  We'll now use Scarlets velocity to head east, and use the clockwise swirl velocity of the eddy to spin us up to the north, over to the east, and back down to the south.

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Looking downstream in the altimeter data, we are about 430 km to our next target point of 42.0 N, 13.5 W, a point that is 5 to 10 km inside the Spanish Exclusive Economic Zone, depending on how you measure it.    We'll follow the wavey line of eastward currents in, so our path will be a little longer, but we'll get the boost from the currents. Assuming we make about 15 km/day from here on out, its about a month to get there.

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If we look at the satellite Sea Surface Temperature map for the same region, we see a similar wavy pattern in the temperature front between the warmer oranges and yellows, and the cooler greens and blues.

 

 

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Overlaying the two satellite products, we see good agreement between the two products derived from different satellites.  Its always good when views of the ocean from different satellites agree.  The cold water flowing south from the Spanish EEZ into the Portuguese EEZ is especially prominent.  We anticipate that the agreement between these two satellites is going to work in our favor for path planning over the next month.

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Moving over to Drake, progress continues to northeast.  We are 75 km from the waypoint, a distance that will be covered in about 4 days.   We'll adjust the waypoints to turn east once we hit 26.5 N.

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