Archive for July 6th, 2008

Following the Navy’s Ocean Forecast

Sunday, July 6th, 2008

RU17 officially flew off the map yesterday, leaving guidance from our own satellite receivers behind.  The Scarlet Knight has clocked 3,143 km to get to this point.

Currents are steadily decreasing on the way out of the cold eddy we just left behind.  Not a bad exit.  We were hoping to leave the ring as currents hit NE, a heading of 45 degrees.  Looks like we got to a heading of about 60 degrees.  Not bad at all.   Currents from the last reported surfacing are heading ENE - so are we.  Nothing like a tailwind.

Switching to the global Sea surface themperatures, we need to work on a new product over the coming week.  The existing product show below is designed for long-range planning.  We'll put together a new enhanced zoom for the local glider area.  Satellite imagery is nice like that.  Multiple scales are easy.

Altimetry is still a bit perplexing. That high (red) centered near 40N, 44W should be giving us currents to the northwest based on our present position, 38 40'N, 44 53'W.  But RU17 is still seeing currents to the northeast, just like the Navy model forecast.  Paraphrasing a 1980's quote from Alan Robinson, thats the power of dynamical interpolation that you get from a model.  F=ma is still a powerful constraint. 

So we will continue on this path for a bit. We are flying in what the Navy model says is a region of favorable (eastward) currents in between to regions of unfavorable (westward) currents.  if the altimtry eventually proves right, possibly by a displaced high, we are also in a good position to follow it around to our destination, the general area of 40 N, 40 W.