The Knorr left the dock promptly at 8:30 this morning. So far the weather is good and seas are calm.

News from the Strasse Cruise

Dear Ray,

We are continuing our meso-scale survey which should be over by Sunday afternoon, as well as the deployment of most of the drifters. What we find at meso-scale fits quite well with the latest analyses (on www.locean-ipsl.upmc.fr/smos/spurs, as well as some data and a few plots placed there with some delays, as the Paris computers suffered from the heat a week ago).

The eddy centered to its south-east is actually proving to be rather energetic, and you might well feel it during your cruise in a month further west! Hopefully a good portion of the drifters might remain trapped in its circulation and thus flow at some point towards the west (right now they flow to the southeast along the eddy edge).

There is also some indication of the saddle point near our north-east corner with the less salty water arriving from the north, and the TSG/scanfish/autonomous sailing vessel/gliders survey show very clear fronts near the edge of the eddy. This should clearly be the scope of our investigations next week, which we might start on monday, weather permitting.

We have started last night the first long (2-day) deployment of ASIP. So far, so good (deployment between the saddle point and the eddy's edge), with quite strong inertial oscillations (we had finally some trade winds starting 36 hours ago, after 3-4 days of very calm weather and surface waters reaching over 29°C in the early afternoon! You would not have believed that we were a little to the east of the center of the gyre, and we kind of roasted on the deck!).

We will continue have the two gliders circulate around the area (to make it simple, probably in a square box), and we might try to get them to drift with the barycenter of the drifters, but this might be hard due to the features that we decided to investigate. At the end of the cruise, we will interact more with you (please, provide us with your Knorr's adddress so that the two gliders can meet your ship and contribute to your survey before their recovery).

With best regards, Gilles.

PS: I'll be delighted if you pass it to the rest of the Spurs sea-going team.

PS2: our dry-land team might be happy to complement this short report soon.

Current Science Party List

KNORR209-01 Science Party

Name	Affiliation	Email
Raymond W. Schmitt	WHOI	rschmitt@whoi.edu
Lou St Laurent	WHOI	lstlarent@whoi.edu
Dave Fratantoni	WHOI	dfratantoni@whoi.edu
J. Tom Farrar	WHOI	jfarrar@whoi.edu
Chris Duncombe Rae	WHOI	duncombe@whoi.edu
Steve Falutico	WHOI	sfaluotico@whoi.edu
Ken Decoteau	WHOI	kdecoteau@whoi.edu
Jeff Lord	WHOI	jlord@whoi.edu
Jason Smith	WHOI	jsmith@whoi.edu
Ben Hodges	WHOI	bhodges@whoi.edu
Julian Schanze	WHOI/MIT	schanze@mit.edu
Alec Bogdanoff	WHOI	abogdanoff@whoi.edu
Oliver Sun	WHOI	osun@whoi.edu
Eric Lindstrom	NASA	eric.j.lindstrom@nasa.gov
Fred Bingham	UNCW	bigkahuna@fredbingham.com
Andrew Whitely	UNCW	aew4597@uncw.edu
James Riley	UMASS Dart	u_j2reilly@umassd.edu
John Shanley	PMEL	John.C.Shanley@noaa.gov
Andrew Meyer	PMEL	Andrew.Meyer@noaa.gov
Andrey Scherbina	UW	ashcherbina@apl.washington.edu
Jesse Anderson	UW	jessea2@uw.edu
Phil Mele	LDEO	pmele@ldeo.columbia.edu
Julius Busecke	LDEO	julius@ldeo.columbia.edu

Cruise Plan Elaborated

All,

Below please find an elaboration on the KNORR cruise plan, with a  timeline and figures. This was assembled with input from a number of  people who provided details on their sampling plans. I welcome further  comments from everyone as we continue to refine the plan.

Next Monday at 2pm Eastern time we will meet locally with the Ships  Scientific Services Group and Marine Ops people to go over nuts and  bolts issues about the KNORR. It will be possible for interested parties to join by conference call, though this is not a discussion of  the cruise plan itself, just an opportunity to make sure we have the ship's equipment and personnel we need.

We can have a conference call on the draft cruise plan itself sometime next week.

I will soon be needing lists of the personnel joining the cruise. I understand that we do not need visas to enter the Azores.

Thanks, Ray

The basic constraints for the Knorr cruise:

Dates: Depart WH Sept. 6 – Arrive Punta Delgada, Azores, Oct. 9, 33 days at sea Distances: It is 1915 nm from Woods Hole to 25° N 38° W, about 8 days of steaming. It is 993nm from 25° N 38° W to Ponta Delgada, about 4 days of steaming. This gives our working time on site of about 21 days.

My thinking is that we can spend roughly one week deploying assets, including moorings, floats and gliders, about one week doing a small “control volume” with repeat surveys around the moorings, and about one week doing a feature survey, targeting a front or eddy identified by the satellites and models. Of course, we must always figure on some time lost to weather or chasing down the errant glider, but this is a general outline.

The moorings will require bathymetric surveys of the sites before finalizing line lengths; Tom requests that we do the surveys for all three sites first so as to give time for the mooring groups to set up. Surveying will not take long, and can be done at night; the three moorings should take no longer than three days to deploy, so long as the weather is reasonable. Obviously, some gliders, floats and drifters could be deployed during this time as well.

Steve is planning deployment of his 25 profiling floats in a 5 x 5 grid with 30 km spacing. If we steam this with a “radiator” pattern this would take about 2 days. I imagine this would be the best time to deploy the gliders, though perhaps they can self-position and get to their survey lines on their own, so could be deployed as soon as we are in the area.

The control volume around the moorings will be done with an Under Way CTD while steaming, ships ADCP, then microstructure and CTD/LADCP casts at the corners. The idea is to hit the corner stations on a 7 hour cycle, so we get four in an inertial period (~28 hrs). The corners could be the moorings or some wider square. A turbulence glider would be doing the legs, and it may be an excellent pattern for a wave glider as well. If we do this for 6 days we cover 5 inertial periods.

This would allow us about a week to chase down and survey an interesting feature (front or eddy) suggested by the satellites and models. Surveys could be stars (eddy) or butterflys (front) and the UW-CTD, CTD/LADCP and microstructure profiles will be appropriate assets. 

Draft SPURS Cruise Timeline for KNORR, Sept. 6- Oct. 9, 2012

Sept. 6: Depart WH (~10am? high tide = 11:48 am) Steam for 25°N, 38°W Sept. 8: 1 test station (CTD/LADCP ~ 1hour)Sept. 9: 1 test station (microprofiler)

Sept. 10: 1 test station (glider, etc)

Sept. 11-13: Continue steaming with test stations as needed

Sept. 14: Deploy NW Seaglider near site. Arrive at 24° 45’N, 38° 02’W, Begin survey bottom at 3 mooring sites (Figure 1)

Sept. 15: deploy WHOI mooring

Sept. 16: deploy North PMEL mooring

Sept. 17: deploy East PMEL mooring

Sept. 18: steam and deploy Seagliders (Figure 2), ARGO floats, (5x5 grid for the 25 floats, 30 km spacing, ~2 days to do radiator pattern, Figure 3), Wave Gliders, 15 Surface Drifters

Sept. 19: steam and deploy floats, surface and mixed layer drifters

Sept. 20: weather day or retrieve wayward glider or deploy mixed layer drifters

Deploy T-Glider and begin control volume survey with U/W CTD, and micro-

Sept. 21: structure and CTD stations at the mooring locations, ~7 hrs between stations, 4 knot steam with U/W CTD, inertial period ~28 hrs. (Figure 4).

Sept. 22: Control volume survey with U/W CTD, and micro-structure and CTD stations

Sept. 23: Control volume survey with U/W CTD, and micro-structure and CTD stations

Sept. 24: Control volume survey with U/W CTD, and micro-structure and CTD stations

Sept. 25: Control volume survey with U/W CTD, and micro-structure and CTD stations

Sept. 26: Control volume survey with U/W CTD, and micro-structure and CTD stations

Sept. 27: End box survey after 6 days (5 inertial periods), retrieve T-Glider, identify salinity frontal feature with input from satellites and models 

Sept. 28: Steam to feature site, deploy surface drifter cluster, begin feature survey

Sept. 29: Feature survey (star or butterfly) pattern with U/W CTD, and micro-structure and CTD stations

Sept. 30: Feature survey with U/W CTD, and micro-structure and CTD stations

Oct. 1: Feature survey with U/W CTD, and micro-structure and CTD stations

Oct. 2: Feature survey with U/W CTD, and micro-structure and CTD stations

Oct. 3: Feature survey with U/W CTD, and micro-structure and CTD stations

Oct. 4: Feature survey with U/W CTD, and micro-structure and CTD stations

Oct. 5: Check moorings, CTD stations at moorings, retrieve some gliders, begin steam for Azores

Oct. 6: Steam toward 25° N 35.5° W to deploy 7 surface drifters east of SPURS site

Oct. 7: Steam

Oct. 8: Steam

Oct. 9: Arrive Punta Delgada, Azores 

Figure 1. Mooring sites with bathymetry: WHOI mooring at 24°34'N, 38°02'W PICO-East at 24°34'N, 37°49'W, PICO-North at 24°45'N, 38°02'W

Figure 2. Seaglider survey plan. 2 gliders would occupy a 140km x 140 km box centered on the WHOI mooring (red/blue), a third would perform a 50 km scale butterfly pattern around the mooring (purple).

Figure 3. Float deployment positions around central mooring. These are within the 140 x 140 km box defined by the Seagliders (plot border).

Figure 4. UnderWay CTD survey volume around moorings with microstructure and CTD/LADCP profiles at moorings. 

Endeavor Cruises 2013

All,

I have been in discussions with the Marine Superintendent at URI about the Endeavor cruises in 2013.  Endurance is limited to ~30-31 days so the tentative plans are:

Spring cruise:   Depart GSO/Narragansett March 19, 2013, 8 day steam to site, two weeks on site, return to Panama City Florida.

Fall cruise: Depart GSO/Narragansett October 8, 2013, 8 day steam to site, two weeks on site, return to Port Everglades Fla.

We will not be doing mooring deployments on the Spring cruise, nor microstructure surveys on the Fall cruise, so hopefully this will give us sufficient time.

These are the dates that they will propose to UNOLS, so just pencil them in for now.  FYI.

Cheers, Ray

New Proposed Locations for Moorings

Below is the gridded bathymetry for the area near the central flux mooring, with the original proposed locations (black symbols) of the flux mooring (star) and prawler moorings (circles). The new locations are shown by the red symbols. The moorings have been moved to be in an area with flatter, more predictable topography.

Here is an explanation from Billy Kesler:

We had a phone conversation among the mooring people here and at WHOI Wednesday and I think we've agreed that this little plateau is our target for the array center. The WHOI mooring will be about 25nm south and 2nm west of its nominal position. I guess that means that everything else we do will correspondingly shift south. That shouldn't affect anything about the features we will sample, since the choice of 25N,38W was nominal and approximate, but the mooring ops look a lot easier at the new position. We don't think it makes any difference to have the PMEL moorings rotated relative to the WHOI mooring, either, as long as this remains a right triangle so we can calculate gradients.

The idea is that we don't want to get out there and find that we're trying to deploy a mooring on a steep slope, and end up having to move one of them, and then get stuck with some kind of non-right triangle or inconsistent distances between them. The plateau means that we can probably get close to our target 20km-separations and right-angle configuration.

This is not final. We're in the process of checking this with other bathymetry data; obviously a gridded bathymetry without a real survey is approximate!

12-05-24 Draft Cruise Plan

 To: SPURS investigators

Re: SPURS cruise planning

Date: May 24, 2012

I have been working on the cruise plans for our upcoming SPURS field work and welcome your input and feedback on this general outline. A more detailed breakdown of the shiptime is in the works but I wanted to share this outline to get us all on the same page.

Some basic constraints for the Knorr cruise:

Dates:        Depart WH Sept. 6 - Arrive Ponta Delgada, Azores, Oct. 9, 33 days at sea

Distances: It is 1915 nm from Woods Hole to 25N, 38W, about 8 days of steaming.
                    It is 993 nm from 25N, 38W to Ponta Delgada, about 4 days of steaming.

This gives our working time on site of about 21 days.

My thinking is that we can spend roughly one week deploying assets, including moorings, floats and gliders, about one week doing a small "control volume" with repeat surveys around the moorings, and about one week doing a feature survey, targeting a front or eddy identified by the satellites and models. Of course, we must always figure on some time lost to weather or chasing down the errant glider, but this is a general outline.

The moorings will require bathymetric surveys of the sites before finalizing line lengths; Tom requests that we do the surveys for all three sites first so as to give time for the mooring groups to set up. Surveying will not take long, and can be done at night; the three moorings should take no longer than three days to deploy, so long as the weather is reasonable. Obviously, some gliders, floats and drifters could be deployed during this time as well.

Steve is planning deployment of his 25 profiling floats in a 5 x 5 grid with 30 km spacing. If we steam this with a "radiator" pattern (with approximately upwind/downwind legs) this would take about 2 days. I imagine this would be the best time to deploy the gliders, though I understand that they can self-position and get to their survey lines on their own, so could be deployed as soon as we are in the area.

The control volume around the moorings will be done with an Under Way CTD while steaming, ships ADCP, then microstructure and CTD/LADCP casts at the corners. The idea is to hit the corner stations on a 7 hour cycle, so we get four in an inertial period (~28 hrs). The corners could be the moorings or some wider square. A turbulence glider would also be doing the legs, and it may be an excellent pattern for a wave glider as well. If we do this for 6 days we cover 5 inertial periods.

This would allow us about a week to chase down and survey an interesting feature (front or eddy) suggested by the satellites and models. Surveys could be stars (eddy) or butterflys (front) and the UW-CTD, CTD/LADCP and microstructure profiles will be appropriate assets. This gives us an opportunity for discovery. One option is to steam south into a region with stronger surface salinity gradients, though there would be some loss in survey time. A cluster deployment of surface drifters would be possible if the drifter working group decides this is worthwhile. The working group is presently discussing deployment strategies.

I am looking for feedback on this general plan. Let me know your specific deployment needs, so that we can work them into the detailed plans. I want to know about expectations for things like whether CTD casts are required on deployment of various assets. (I understand that none are needed for the floats, but how about for the gliders?). Do the mixed layer floats require a steam to the east to get "up-stream"f the site? If so, how far?

Let me know your expectations for your participation in the cruise and I will work them into the detailed plan.

Thanks,
Ray