Archive for July 29th, 2008

All in slow motion

Tuesday, July 29th, 2008

RU17 continues to head in towards the center of a large loop it is now making to the north.  We are in a band of warm water that runs north-south. We are using the glider velocity to head east, across this band.

Currents (below) have that consistent eastward component.  A good thing.  Altimetry says if we keep going east, we get into a patch of currents to the south and east.

We continue to make progress trying to cross that front from the warm water into the cold.  The southern side of that cold region is believed to have strong currents to the east.

We are learning the value of a good forecast. Everything happens slowly in the world of gliders, and the ocean changes in the mean time.  Trying to puzzle out the exact circulation in that cold region remains difficult.  We have altimetry and two models.  We can see features that are similar in all three, but the locations are shifted.  Hard to say what that colder water has in store for us.  Guess we won't know till we get there.  Uncertainty - a difficult one today.  My favorite image of them all is below.  It is the east-west component of the current in the NLOM model.  Reds are east, blues are west.  On this northward run of RU17. you can see how the track was drifting west in the blue, and as soon as it hit the read, it started drifting east. We hope to stay in these eastward velocity filaments for a bit.