New Drifter Designs

We have been experimenting with alternative designs this summer in an effort to further reduce the cost and time needed to build surface drifters. Several new prototypes were built and tested in local Woods Hole waters including the:

1. “Shawn Drifter” which has a 4 by 4 wooden mast and a flotation collar

2. “Miles Drifter” which has a 4 by 4 PVC fence-post mast filled with 2-part foam

3. “Eddie Drifter” which has a 2 by 4 wooden mast and a flotation collar

4. “Vitalii Drifter” which is a mini-rachel drifter that uses a Garmin instead of a TrackPack

Figure 1. The new “Eddie” drifter with a wooden 2-by-4 mast and collar flotation.

The first three are slight variations of the standard “Rachel Drifter”. The Eddie model (see photo below) holds the most promise in replacing the Rachel as our standard surface drifter. While the first Eddie prototype failed after a few days, the 2^nd has been reporting regularly for 3 weeks. Not only is this drifter a bit more environmentally friendly, it is much easier to make and should cost hundreds less. More info on these alternative models is posted with photos on the “drifter deign and technology” link on the drifter website http://www.nefsc.noaa.gov/drifter

Gulf of Mexico Drifter Deployments

A couple dozen drifters were shipped to various labs on the gulf coast including University of South Florida in St Petersburg, Dauphin Island Sea Lab in Alabama, and NOAA’s Atlantic Oceanogrphic and Metereoology Lab in Miami. They were also sent down on both the R/V ENDEAVOR and the R/V DELAWARE to be deployed at various locations around the gulf. The tracks of these drifters can be viewed at http://www.nefsc.noaa.gov/drifter/drift_BP_Spill.html . They are contributing to a multi-lab effort to understand the transport of the oil around the entire gulf as can be best seen at the USF site http://ocgweb.marine.usf.edu/~liu/drifter_all.html .

Proposal Plans

We hope to submit a planning letter to NOAA’s Environmental Literacy Grant call for k-12 education projects in early September. Partnering with MATE, SMCC, GoMLF, and many New England-based marine educators, we hope to follow-up on what we have been doing for years: engaging students in drifter designing. building, and tracking. The idea would be to have marine science students at local college visit local high schools to teach educators, service providers, and students how to build drifters. The drifters will be deployed in offshore waters by fishermen.

Highlights of 2010 Drifter Deployments

More than 200 of the SMCC/GoMLF/NOAA drifters have been deployed this year, more than any year prior. While many of them were short deployments of just a few days or weeks in estuarine/coastal waters, some have traveled offshore waters for months. The raw statistics as posted at http://www.nefsc.noaa.gov/drifter/statsd.html show many of them that have each logged thousands of kilometers.

One of the most interesting tracks is that of unit # 105440672 which has been retained in the enormous tides of Bay of Fundy for nearly 3 months and is still traveling. While it has traveled a total distance of over 5000 kilometers, it is still only a few hundred kilometers from where it was originally deployed.

New Drifter Users

Since the last drifter newsletter, the following institutions have recently joined the cooperative effort to deploy drifters (or plan to do so in the coming year):

• UMASS Dartmouth Ocean Mixing Lab

• Sea Education Association

• URI Narragansett Bay Project

• Upper Cape Cod Regional High School

• Woods Hole Science and Technology Education Partnership

• NOAA’s Great Lakes Environmental Research Laboratory

Overlaying drifter tracks on sea-surface temperature images

MATLAB code has been developed to better visualize the relationship between SST structure and the path of drifters. The set of routines does that following:

• browses remotely stored images at Rutgers University,

• saves “good” images,

• interpolates in time between good images,

• interpolates in space over cloudy images,

• generates animations of the drifter tracks on color-contoured imagery.

Thanks to Emily Motz, a summer student from SUNY Maritime School who has spent her summer in Woods Hole with the “Partnerships in Education Program”, the code has produced these animation at, for example:

http://www.nefsc.noaa.gov/epd/ocean/MainPage/anim/sst_may2010/sst.html

The next phase of this project will overlay circulation model vectors. We are also developing a Phython application for drifter processing and visualization which will not require a MATLAB license.

ComTechMobiles satellite fee

As noted previously, there are two ways to pay for satellite fee:

1. one time bill through the Gulf of Maine Lobster Foundation
2. monthly bills from ComTechMobile

Drifter users are asked to be aware of which option they are under and, in the case of option #2, be ready to respond.

More recently the drifter has been showing signs of a potential early death. For days at a time the drifter has failed to broadcast its location. Then, somewhat miraculously, it would raise its head and tell us where it was. At this time it has become reliable again, reporting its position every four hours. Surprisingly, it has once again struck out in a new direction. For the last week, the drifter has been creeping ENE on a beeline for Ensenada, Mexico. Has it overcome its buoyancy problems, or has it been recovered by a fishing vessel that is slowly working it’s way back to port?

One of the real joys of this project has been puzzling over the factors affecting the drifter’s wanderings. Every day has produced new mysteries and revelations.

Then, miraculously, the drifter reported its position WNW of San Diego the day before yesterday (http://www.nefsc.noaa.gov/drifter/drift_redwoods_2010_1.html)! Perhaps a fortuitous wave tipped the GPS unit out of the water for a moment at the precise instance of a position burst.  The drifter may still be in the game! Unfortunately it is unclear if, or when, it may transmit its location again. In any event, Mexican waters appear to be next on the itinerary.

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In that time we have developed a fairly good idea of where California’s coastal currents are likely to carry our bottles. During our storm season, the nearshore Davidson Current tends to transport our bottles northward. We have very high recovery rates during those times in northern California, Oregon, and Washington. On occasion our bottles have made it as far as British Columbia and Alaska. The Davidson Current tends to be best developed between mid-October and mid-February, but southerly storm winds in late spring and early summer often produce the episodic, short-lived appearance of the Davidson Current.

The California Current, on the other hand, sweeps close to shore during much of the rest of the year. Our drift bottles are usually carried southward during these times. If you’ve been following this blog, you’ve undoubtedly noticed that our drifter has been swept over 200 nautical miles southward in the last month, successfully avoiding all of the most common stranding sites. During this time of year, most of our drift bottles are recovered along the Mendocino, Sonoma, and Marin County coastlines (counties that are north of the Golden Gate). Some of the bottles are carried south of the Golden Gate as far as Monterey County. The farthest south any of our bottles have ever been recovered is Big Sur.

Our drifter is now about 40 n.m. offshore along the Monterey coastline and rapidly approaching the latitude of Point Sur. For the last 25 years, the burning question has been, “Where do the bottles go if they don’t strand north of Big Sur?” Two of our bottles were recovered (several years apart) in the Philippines, but we have no other recoveries south or west of Pt. Sur. So, at long last, our drifter is on the verge of shedding some light on the mystery of where the surface currents carry our drift bottles.

The Monterey Bay, however, presents a new set of challenges. The currents there are notoriously variable as witnessed by Monterey Peninsula College’s two deployments of their drifter over the last seven months (See their posts  from November 17th of last year and February 3rd of this year). The excitement is building here again as the drifter approaches its next aquatic hurdle. Wake up Deidre, there’s some jetsam heading your way!

Students in the Marine Science Technology Program (MST) have recently built and deployed an ocean drifter designed to study California coastal currents. The drifter is a four-and-one-half foot tall by four foot wide structure made of PVC pipe, vinyl “sails” and a package containing a satellite transmitter. The drifter is designed to float just below the surface of the ocean so that its path is largely unaffected by the wind. A satellite tracking device protrudes above the ocean surface so the path of the drifter can be monitored by MST students, scientists and the public.

It was dropped into the Pacific Ocean on Tuesday May 11 with the help of the F/V Trek II about two miles offshore of Noyo Bay. The students have been waiting for ideal oceanographic conditions to drop the drifter to utilize the dominate California Current that flows from north to south, fueled by a northwest wind pattern. Strong northerly winds also foster coastal upwelling that pushes surface waters offshore. Upwelling brings cold, nutrient-rich waters to the surface and sustains the tremendously diverse coastal ecosystem along the Mendocino Coast. Information gathered by the drifter will be used in future MST Program classes, such as the Oceanography class that will be offered this coming fall semester. Even if ocean currents force it up on the beach, the drifter can be recovered and redeployed unless it is too damaged.

Funding and support for the project came from the Marine Advanced Technology Education (MATE) program in Monterey via a grant from the National Science Foundation. Scientists from Woods Hole Oceanographic Institute in Massachusetts provided materials and technical support to assist CR students to assemble the drifter, and the federal National Oceanographic and Atmospheric Administration (NOAA) has donated the satellite time to track the drifter.

Marine Science Technology students on the Mendocino Campus are hoping to see how changes in wind and currents affect the path of their drifter. Watch the MST web page (http://www.redwoods.edu/Departments/Marine/) for a future link that will allow you to track the path of the drifter along with the MST students. You can access a real-time google map with the drifter location updated every four hours at the following address: www.nefsc.noaa.gov/drifter/drift_redwoods_2010_1.html

© Copyright College of the Redwoods

The wind direction has  shifted back to the NW, so the drifter may be driven southward again. On the other hand, there is a spring flood tide cresting around 11:30 tonight that could drive the drifter closer to the bay. All of these options are only possible if (and this is a big IF) it manages to avoid the heavy ship traffic sailing into the bay. Watch with us on our Google Map page at,  http://www.nefsc.noaa.gov/drifter/drift_redwoods_2010_1.html

The NWS offshore forecast for the next four days calls for more unseasonal southerly winds (is this really MAY?), which could once again subject our valiant drifter to the possibility of being pushed back northward and onshore. Thus the potential for a visit to the Big City still remains a possibility.

Both of our local newspapers published articles on the drifter project (one on the front page), and tracking the drifter has become an obsession for many members of the general public as well as our students. Thanks to each and all of you (especially Jim Manning & Deidre Sullivan) that are responsible for making this project happen!

A weak front is predicted to slip through the area today, and with it will come southerly winds. Southerly winds could produce a northerly current, and more significantly, an onshore flow. The front is predicted to move through quickly, and our usually reliable NW winds should return tomorrow. Today produces another round of anxiety among the students and staff following the journey of the drifter. Will it be driven onshore today, or will tomorrow’s northwesterlies power our drifter past Point Reyers?

Regardless of the drifter’s immediate fate, the drifter has proven to be one of the most dynamic and powerful teaching tools I ever had. Each day’s odyssey has been a string of teaching and learning opportunities for all of us.