Monday, March 31, 2008
A successful weekend



Still no satellite imagery, so we will fly by the temperature and swirl velocity record. Keep the temperatures decreasing, the swirl velocity decreasing as we head to the north. Our present set of waypoints is based on the position of the ring on March 28, about 3 days ago. Rings propagate to the west, a few kilometers a day. Assuming a relatively fast speed of 5 km/day, we may be adjusting our waypoints 15-20 km to the west over the next day or so as we move up the western side of the ring.
Sunday, March 30, 2008
Closing the Loop


Temperatures are cooler on this lap. Yellows are 14 C, oranges are 16C.
This morning we will change the waypoints and start drawing the glider out into the colder and slower parts of the eddy. This will require several waypoint changes today. If we pull too hard, we leave the eddy, and don't make our destination. If we don't pull hard enough, its another lap or we miss the target ring on the northeast.
Saturday, March 29, 2008
Another Lap






We seeing cooling in the right hand side of the glider section to the same 14-16C temperature range.
Right now our target waypoint is 39 20 N, 63 30 W. Fine for the overnight shift while we are at the north side of the ring. We just want to start sweeping around to the south, and the swirl will do most of that for us.
As the day goes on, we will want to shift that point farther out in the ring. Right now it is inside the warm center and inside the first lap we took around.
In this case, instead of flying towards a point, we want to fly away from a point. In this case the point we want to fly away from is the center of the eddy. This is a new and interesting behavior for a glider. We care most about using all the glider velocity to go away from the center and we care less about where the swirl velocity takes us. We can time our exit to sweep us around to about where we want to be.
RIght now we can only fly towards a waypoint, so to accomplish this most effectively right now, we would have to set a new waypoint outside the eddy every time the glider surfaces, which is a bit impractical on a long duration mission. So lets try this by setting four waypoints between here and where we want the glider to be on the other side sometime sunday or monday.
1) 39 30 N, 63 00 W, outside the ring in the cold 6C filament wrapping itself around. When we get close, say within 20 km, we switch to:
2) 39 00 N, 63 30 W, just on the southern side of the ring, and on the outer edge. Again, when we get to close (say 20 km), we switch to
3)39 30 N, 64 45 W, at the easter side of the ring, possibly pulling it out. If the temperatures are staying warm and velcoties high, we will have to adjust this point west a bit, say another 15 minutes to 65 00 W. We can make that call as we round the southern side. Then we go for the base of the new eddy and fly up its wester side buy going to
4) 41 00 N, 65 00 W.
Lets give something like this a try over the weekend.
Friday, March 28, 2008
Fighting our way out


We want to see these temperatures decrease as well as the currents
to indicate we are leaving the eddy on the north side.
Thursday, March 27, 2008
In the Warm Ring

Wednesday, March 26, 2008
Free Coffee & Wireless in San Juan


Consistent with entering the ring on the southeast side.

followed by 40 45 N 64 45 W, (towards northwest.)
Tuesday, March 25, 2008
Into the Warm Ring
Monday, March 24, 2008
From Old San Juan


Here are the current speeds. Slowed down to about 20 cm/sec. Now we can fly where we want.

Here is the present location, and the small current velocity vectors. We are currently at 39 o4 N, 62 37 W. We'll need to change the waypoint sometime soon, like anytime between tonight and tuesday morning. Exact timing doesn't matter so much because of the slow current speeds. Someone can do this when they are rested. A good place to head will be along the southern side of the ring, towards 39 30 N, 64 00 W. The stronger currents are inside the ring, in the orange in the SST map which is about 18C.

Here is the present location, and the small current velocity vectors. We are currently at 39 o4 N, 62 37 W. We'll need to change the waypoint sometime soon, like anytime between tonight and tuesday morning. Exact timing doesn't matter so much because of the slow current speeds. Someone can do this when they are rested. A good place to head will be along the southern side of the ring, towards 39 30 N, 64 00 W. The stronger currents are inside the ring, in the orange in the SST map which is about 18C.
If we head to this point, the strong currents will sweep us around to the west along the southern side of the ring. Could be fun.
Sunday, March 23, 2008
A new route home

Once RU15 is in the ring, we see the new exit point now on the northwest side. The idea is to leave the ring where you see the warm (yellow) water heading towards the shelf break. This region will have favorable currents. The cold (blue) water is shelf water, and unfavorable currents for our northward journey.

Above are the current vectors for the last 2 days. You can see the sharp decrease as we leave the Stream, and now the currents are starting to turn. The present waypoint if perfect for now, perpendicular to the currents, pulling us northward into the ring. As soon as the currents switch direction and flow to the west, likely sometime tomorrow during the day, we will switch to a waypoint on the west side of the ring. The current waypoint is on the east side. The new waypoint will be somethin like 39 30 N, 63 45 W. The idea is to put this point on directly west of the ring center, and more than 2/3 of a ring radius out. Because the ring is moving west, subsequent imagery may make that new waypoint as far as 39 30 N, 64 00 W.

Saturday, March 22, 2008
Hit 15 C - Leaving the Stream

Sea surface temperature image form March 19 still the best. Right around 63W -62W, the Stream is heading nearly due east, and the is a perfect Warm Core Ring to the north. Thats were we'll head.

Here we use the slow glider speed to fly perpendicular to the current and swim us out of the Gulf Stream as the Stream pulls us to the east. The velocities drop rapidly as soon as we cross out of the Gulf Stream and into the 15C Slope water. We'll continue heading north, likely with currents running slowly to the east till we hit about 39N. At that point we'll start seeing the switch in direction. As we enter the clockwise rotation of the warm core ring, the currents will pick up heading towards the west, and will sweep us around to the north. Our target here is the warm water heading towards the shelf break. If we can keep the glider temperatures near 15C, we'll be getting good currents. If the temperature drops down to the 6C-9C range, we are in shelf water thats flowing against us.
A nice day of work at sea. We are currently at 63 16.87W longitude. Our target was to leave the Stream somewhere between 63 30 W, and 63 00W. I'd call this one a bullseye. Hats off to the glider pilots on this one.
Time to Exit


Clouds still cover most of the gulf stream we are interested in, Cold air blows over the land from the northwest, heads out to sea over the cold water and stays clear, then hits the warm stream and clouds appear. Typical wintertime scenario. Donglai knows the winds are from this direction, Louis talks of the cloud formation. RU15 is in a strong current to southeast. As it makes this turn, around the bottom of the trough, we want it to start heading to the northeast, then north to get out of the stream. A good way to do this will be to use all the glider velocity to head to the north, and let the Stream do the east component. This means we just head the glider towards the point where we want to pick up the warm ring. That point is number 3 on my waypoint list in the powerpoint I sent last night. The present location, point 2 and point 3 line up almost on a straight line at this time. It flies nearly corner to corner on a 1 degree square. Present location near 38 N, 64W, intended location is 39 N, 63 W. Corner to corner on a 1 degree square should be about 140 km at this latitude. The location of point 3 is 39 00 N, 63 00 W. It will fly us perpendicular to the current. I think the waypoint has to be less than 200 km away for it to be accepted as valid. If it is too far, the second point in my waypoint list still splits the difference. it goes to 38 30 N, 63 30 W. The more distant waypoint (#3) has the advantage of giving us a longer time before we have to change waypoints again. If we need to use the second waypoint, one way to do this is to put the second waypoint in with a big watch circle or about 25 km. As soon as we get close, we go to the third waypoint. If it looks like we are going to miss the second point, then we take over manually and switch to the third. If we miss the waypoint on this surfacing, that is ok. Dave has it going to a point along this same track. RU15 is getting close to the point Dave set early this morning, so we will have to change it soon anyway.
Thursday, March 20, 2008
Around the bend
Wednesday, March 19, 2008
Exit Strategies

The white clouds in the imagery always seem to be worse the further east you go. Its a lot easier to fly these things when you have that bidrs-eye view from space.
Down in the trough
So here is where we are. Shooting along the bottom of this meander trough traveling at speeds we have hardly ever seen before.
The next satellite shot shows the Gulf Stream in this vicinity quite well.

We'll make our next waypoint during the next surfacing later tonight, then turn left and head north into the next meander crest.
There is a warm ring up there at the top of the crest near 66W that we can use to slingshot us back to the shelfbreak if we need to. But most likely we'll skip this ring, unless we need to go back to Nantuckett. We'll at least shoot for the warm ring near 63W. Its our first possible exit point if we want to make Halifax.
An assist from our Dalhousie family!
Marlon Lewis gets us connected to the ice forecasts. It would be good to get the undergraduates tracking this on a weekly basis. Marlon's inspiration and web link are below
"Hi Oscar; You should be OK until Grand Banks or so (same message they sent to Titanic). Here is the most recent - the main site to check is: http://ice-glaces.ec.gc.ca/App/WsvPageDsp.cfm?ID=1&Lang=eng "
Best, Marlon
AND IF THERE IS A STORM THERE IS........
Tuesday, March 18, 2008
RU15 on ICOOL Mission #001
At 6:30 am on a Tuesday morning exactly 1 year ago, the RV Lucky Lady left the New Bedford docks with RU16 on board. RU16 is one of our underwater robots, a Slocum Glider, built by Webb Research in Falmouth. It was our 100th Glider mission, and to celebrate, we decided we would attempt the first underwater flight from Massachusetts to New Jersey. With UMass Dartmouth, we deployed RU16 just offshore New Bedford on March 13, 2007, and recovered it in Tuckerton, NJ on April 6, 2007.
Since then we've repeated the MA to NJ flight 5 times. We also sent two gliders south from Tuckerton on interstate trips to Rudy Inlet by Virginia Beach that were picked up by UNC, ODU and UMaryland.
With a year of confidence building behind us, Hugh Roarty decided we were ready for a greater challenge. This time our goal was to fly underwater from New Jersey to Canada. This time our robot would be RU15, the first Slocum Glider equipped with the new "Digi-fin" tail fin, a more rugged assembly designed for longer duration flights.
But beyond the distance, the challenge with this flight is that a straight shot along the coast to Canada is against the current (5 cm/sec to the south as our friend Bill Boicourt recently reminded us at that Italian restaurant in Baltimore). So we chose a different route. To get to Canada from NJ, we will first fly across the continental shelf, cross the dangerous shelf break, then fly across the slope sea and into the Gulf Stream. The Stream will whip us to the east, where eventually we will jump out and ride a warm core ring back to the shelf break off Canada. We'll use our remaining battery life to re-cross the continental shelf up north.
We'll conduct this mission as part of I-COOL, the International Coallition of Ocean Observing Laboratories. We formed I-COOL in Paris in 2005 at a sidewalk cafe with John Cullen from Dalhousie. Our hope is to get this glider at least up to John's office in Halifax, snap a picture, and then repeat as needed.
We kept track of Glider Mission 100 on this blog site. We'll do the same with this I-COOL mission. But we have a little catching up to do. We launched on March 7, 2008, crossed the shelf break danger zone for the first time, survived a storm with 25 foot seas, and caught an extreme Gulf Stream meander crest that is still growing. Right now we are running with the Stream heading southeast into a meander trough that we hope starts to whip us back around to the northeast overnight and into tomorrow. So the next several entries will likely alternate between what we are doing now as we continue on this underwater flight to Canada, and what we did to get us here.
But before signing off for the night on this first entry, we need to add the traditional dedication. For Glider Flight 100, we honored our past. That flight we dedicated to Fred Grassle, our Institute's first Director and the person who brought us all together. For I-COOL Mission #001, we honor our future. We dedicate this flight to our students, 15 years of them to be exact. Through the years they have sustained us, and many times have taught us just as much as we were supposed to be teaching them. We hope they will find this flight as inspirational as we do, and that the thrill of discovery, combined with the personal rewards of teaching others, will sustain them in the challenges they face in a changing world.
Since then we've repeated the MA to NJ flight 5 times. We also sent two gliders south from Tuckerton on interstate trips to Rudy Inlet by Virginia Beach that were picked up by UNC, ODU and UMaryland.
With a year of confidence building behind us, Hugh Roarty decided we were ready for a greater challenge. This time our goal was to fly underwater from New Jersey to Canada. This time our robot would be RU15, the first Slocum Glider equipped with the new "Digi-fin" tail fin, a more rugged assembly designed for longer duration flights.
But beyond the distance, the challenge with this flight is that a straight shot along the coast to Canada is against the current (5 cm/sec to the south as our friend Bill Boicourt recently reminded us at that Italian restaurant in Baltimore). So we chose a different route. To get to Canada from NJ, we will first fly across the continental shelf, cross the dangerous shelf break, then fly across the slope sea and into the Gulf Stream. The Stream will whip us to the east, where eventually we will jump out and ride a warm core ring back to the shelf break off Canada. We'll use our remaining battery life to re-cross the continental shelf up north.
We'll conduct this mission as part of I-COOL, the International Coallition of Ocean Observing Laboratories. We formed I-COOL in Paris in 2005 at a sidewalk cafe with John Cullen from Dalhousie. Our hope is to get this glider at least up to John's office in Halifax, snap a picture, and then repeat as needed.
We kept track of Glider Mission 100 on this blog site. We'll do the same with this I-COOL mission. But we have a little catching up to do. We launched on March 7, 2008, crossed the shelf break danger zone for the first time, survived a storm with 25 foot seas, and caught an extreme Gulf Stream meander crest that is still growing. Right now we are running with the Stream heading southeast into a meander trough that we hope starts to whip us back around to the northeast overnight and into tomorrow. So the next several entries will likely alternate between what we are doing now as we continue on this underwater flight to Canada, and what we did to get us here.
But before signing off for the night on this first entry, we need to add the traditional dedication. For Glider Flight 100, we honored our past. That flight we dedicated to Fred Grassle, our Institute's first Director and the person who brought us all together. For I-COOL Mission #001, we honor our future. We dedicate this flight to our students, 15 years of them to be exact. Through the years they have sustained us, and many times have taught us just as much as we were supposed to be teaching them. We hope they will find this flight as inspirational as we do, and that the thrill of discovery, combined with the personal rewards of teaching others, will sustain them in the challenges they face in a changing world.
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