The Recovery of RU22

Missed my usual morning rounds of RU17 today.  But no worries, the students are driving. Veterans of the Flight to Halifax are on the job. 

Today we were more concerned with RU22 (above).  It was offshore Virginia.  It just completed the Fall sampling run for the southern half of our Mid-Atlantic region for IOOS. We were running low on batteries, currents where pushing us south towards the Gulf Stream faster than we could fly, and a low over Nova Scotia was sending big waves our way.  The forescast was bad as far forward as they forecast. Tom (UMaryland) and Mike (UNC) rented a bigger boat (they are both fans of the small, fast recovery vessels), and were heading out for retrival today, the best of the all bad weather days this week. Many of us were at the annual meeting of our IOOS Regional Association in Fall River, Massachusetts, looking out the window at gray skies and strong winds.  Tom and Mike were going to head down the coast close to shore until they reached the same latitude as the glider, then head out into the waves.  We watched on our blackberry's while they took the hits all morning. Just after lunch, the code message was sent.  RU22 - Bear in the Igloo!  Glider-speak for RU22 was recovered and safe on deck.  At the IOOS meeting, the UMass, RU, and UMaryland glider teams were all smiles. The IOOS glider sampling was successfully coordinated with the fall NOAA Fisheries surveys, and the last glider was coming home.  We had our assimilation dataset for a winter of hindcast model experiments. While we celebrated, Tom and Mike had to battle back against even bigger waves to get back home. We heard the story later in the day at dinner.  We owe them new Mustang suits.

Meanwhile, way out in the North Atlantic, RU17 is in the cold eddy centered near 40.5 N, 36.5 W, now crossing over to the eastern side of that eddy. Our next target is the warm eddy to our southeast centered near 38.5 N, 33.5 W.

The Altimetry above says we should already be feeling the currents to the north, but the glider current time series plot below says thats not the case.  The glider says the currents are still running to the east. So our students have the waypoint set to the south.  The combination of the eastward current and the southward glider velocity gives us the desired path to the southeast.

When will we hit the northward flowing side of the eddy?  From the Satellite Sea Surface Temperature map below there is a band of warm water extending to the north alont 35 W.  That is probably the northward currents we see in the altimetry. if we measure the distance, we are about 30 km from the edge of this warm band.  We should close that distance in a couple of days. Farther to the east, between 34 W and Flores (FLW), we see colder water to the north of 39.5 N is likely associated with the clockwise eddy circulation centered near 40.75 N, 32.75 W.  So we will want to stay south of that front.

About 435 km to Flores.

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