Drifter Trajectory Simulation tool available

From the SPURS web site, under "SPURS Data" and "Drifters" (soon to be replaced by "Drifter Trajectory Simulation"), I released 12 "virtual" drifters, using the "Single Drop Mode".  The velocity hourly data from the ROMS model during August-September 2011 are used to calculate the drifter trajectory.  Currently, there is a limit that each user can release no more than 12 drifters at a time, mostly for computational considerations.  To get the trajectory below takes about 45 seconds.

Simulations

From Rick Lumpkin,

The Ron Brown is unfortunately not going to be able to divert as far as 23N 32W from the PNE trackline, which runs from Bermuda to 20N 38W to 20.5N 23W, then to Eq-23W and finishes in Barbados.  Ship time will be tight, and although there is usually a spare day built into the schedule, all but one of the moorings would still be in the future as the ship is passing south of the SPURS area.  In other words, the chief scientist (Claudia) won't yet know if that spare day is needed for mooring operations, should a problem develop there.

I've run a Nikolai-style simulation using the observed probability distribution functions of all drifters in the area, and released simulated drifters at 20.5N 23W and at 20.3N 28W.  The attached figures show the results, with shading indicating log10(probability) and a star at the SPURS mooring site.  In both cases the drifters are likely to pass south of the mooring at 25N 38W.

Deployment Proposal

Here is a more comprehensive deployment plan proposal:

Let's leave it up for a few days for comments by the group and then we can go ahead with the simulation.

1)deploy 10 SVPS and 10 SVP from the Strasse cruise inside the ~150KmX150Km Strasse box centered at 25N, 36.5W. We hope these drifters will advect westward and enter the small SPURS box in time for the Knorr cruise;
2)deploy 5 SVPS and say 15 SVPs from the Pirata cruise (Lumpkin and Schmid) in September say 23N, 32W tentatively. Again, they should drift N Westward and will enter the SPURS domain;
3)deploy 9 SVPS from VOSs Colibri and Toucan between November and February at ~25N,38W; say one deployment in November (3) one in January(3) and one in February (3)
4)deploy 15 SVPS will by Ray (Knorr cruise) inside the small SPURS box in October say 5 triplets evenly distributed along the north-south eastern side of the box;
5)deploy 7 SVPS east of the Small SPURS domain (25N and 35.5W) at the end of the Knorr cruise;

Best,

Luca and Gilles

wonderful plan, and add in 1 additional 5 SVP and 5 SVPS (from French/Spain funding), that will be deployed in a batch, roughly 15-20 days after the 10 SVPS + 10 SVP array. We are not sure on where those batch deployments will be done, but probably still in the 150 kmx150 km box centered at 25N/36.5W.

Cheers, Gilles.

August Cruise SVP drifter release strategy

Here is a proposed plan for the 15 SVP-S drifters to be tested by ROMS, with a goal to have a uniform coverage with the 200x200 km^2 box centered around the flux mooring at 25N and 38W.

Ideas, comments and suggestions are welcome and appreciated.

-Yi (on behalf of Luca and Gilles)

Drifter Release Objectives and Background

The overall objective of the SPURS drifter component is to maintain an optimal (i.e., uniform) coverage within a mesoscale box (e.g.,  150x150 km2) centered around the flux mooring at 25N and 38W.


We have 15 SVP (15-meter) salinity drifters to be released from the Frence Thalassa/Strasse cruise in August 2012, and 36 SVP-S drifters to be released from the US Knorr cruise in September 2012. 


The ideal deployment plan will have a relatively  uniform coverage within the SPURS mesoscale box from August/September 2012 to March 2013, when the 3rd cruise from US and/or Spanish will return to the SPURS box.


(on behalf of Gilles and Luca)

SPURS ROMS Domains

There are three ROMS model domains with increasing spatial resolution of 9-km (L0), 3-km (L1), and 1-km (L2) but over smaller domains, see the image below. The first implementation of the drifter trajectory tool will be over the L1 domain, but will use the 1-km current in the L2 domain.

ROMS model derived drifter trajectories

The ROMS model has been run during 2010-2011, and this image shows that we are ready to release virtual drifters to help the SPURS drifter working group to design the release strategy.

We will put a tool online in the coming days, so that everyone can release their own virtual drifters, and track their trajectories with time.