Archive for January 16th, 2013

Taking the Leap

Wednesday, January 16th, 2013

Hey All!

While I wrestle with learning the ins and outs of new data sets, our global gliders continue to push onward in the Atlantic.

In a conversation today with Antonio, an interesting topic arose.  We have been brain storming for a while an anomaly in the salinity time series Silbo has been piecing together since deployment off of Gran Canaria.

The waters close to the surface and at depth have become relatively fresh compared to the beginning of the mission.  The waters at depth we recognized as Antarctic Intermediate Water which we have mentioned previously to be part of a subsurface circulation of the Atlantic.  However, Antonio brought up an interesting solution for the fresh waters we have encountered at the surface: Amazon River Outflow.  Apparently, in the past there has been evidence of fresh water flow from the largest drainage basin in the world reaching out across the Atlantic.  This, we think is a question we can answer as we get better at processing ocean models to compare with Silbo's growing data set.

As for the endlessly persistent head current we have seen for months now, it looks like Silbo is now muscling his way between the western side of a cold eddy combined with the eastern side of a warm eddy- resulting in a strong flux to the north:

Depending on how this current evolves over the upcoming days, we may need to shift the way point to try and run with the cold eddy to our south east.  From there we will try and snake our way through the eddy field with the gyration of the eddies.

As for Challenger down in the South Atlantic, she is preparing to make the final leap into deep water, allowing her to fly to the full potential of our deep pump.  According to the position of the last call in, Challenger is flying in roughly 850 km.

Looking at the surface currents from the myocean forecast, we see an inconsistency between the model and what the glider is recording as the depth average currents.

 

This could be for a number of reasons, from low resolution of the model (I may be able to resolve this later in the week), the fact that we are crossing a canyon that may have a strong towards shore flux, or that 29 is flying along a thermal front that may produce a small scale eddy that again may not be resolved by the model.  Over the next couple of days, Antonio and I should be rolling out some new products that we hope will solve our resolution issues.  But we will have more on that tomorrow.

Force, Wind Sea & Honor