Archive for July 27th, 2008

Currents Good – Waypoint Good

Sunday, July 27th, 2008

Currents continue to swing clockwise.  Last night as we left the lab, Josh and I stopped one last time to check on RU17.  It had just surfaced, and we wanted to see the currents. We had a positive vx (velocity component to the east) and it was bigger than vy (the north-south velocity component).  We had not seen that in a couple weeks.  A great way to close out a Saturday night.

Altimetry is still our best roadmap at this point.  We continue circling around the high (orange in plot below), and continue heading the glider to that waypoint between the eddies.  There are three possible routes to the large cold eddy (blue) we see centered near 42 N, 41 W.  The northern route that goes around the high located at 43 N, 43W. The southern route goes around the low near 39 N, 43W, and the route straight across.  The southern route is one we don't want.  That low already gave us a problem once, stopping us dead in our tracks and whipping us south into the influence of another low.  The northern route is much safer, but much longer.  We'll have to try for the straight across 41 N route, and do our best not to get pulled into the southern route.   To accomplish this, we'll keep the waypoint as it is for a day or so to get deeper into this northward current.  The altimetry says we should then start experiencing an eastward flow.  We'll be watching for that. Then as the current starts pushing us north along 44 W, we try to shoot straight east into the current that is going south, hoping to catch the big cold ring near  42N, 41 W.  Its about a 4 to 5 day flight across this region with currents switch from north to south.  A couple days drifting north, followed by a couple days drifting south.  Wow, lots to look forward to.