Turco and Philip Marshall joined the Chugach School District's
Youth Area Watch training workshop held at the Seward SeaLife
Center 10-12 December 2001.
Thirty students and eight teachers from Cordova, Nanwalek, Seward,
Tatitlek, Valdez and Whittier stayed at the Center where they
divided up into six groups to tour the Center's "behind the
scenes", examine all its public exhibits, visit the fish
and shellfish labs of the University of Alaska/Fairbanks Seward
Marine Center next door, and hear presentations from a killer
whale researcher and other scientists.
SALMON's contribution was a 3-hour session introducing the SALMON
Project, discussing marine buoys and satellite imagery, then demonstrating
basic physical oceanographic principles (Coriolis effect, stratification
effects, stratified flows, effects of rotation, vortices, and
Ekman transport among others) before finishing with an introduction
to the circulation of Prince William Sound. Ms. Turco audio-recorded
the entire session for future products on our website and elsewhere.
She also presented a potpourri of marine sound recordings from
her extensive library that enthralled the audience even after
a full day of activities. All participants felt the workshop was
both rewarding and educational and there are plans to present
an educators' workshop in early summer on the above topics. Coordinator
Randy Fleharty did a masterful job of organizing all its diverse
SALMON plans to collaborate with YAW in collecting meteorological
and marine data to assist in our modeling and observing network.
Eight Youth Area Watch high school students and two teachers from Cordova, Seward, Talkeetna and Valdez, Alaska, attended the inaugural field workshop on oceanographic drifters organized by the SALMON Project and held in Seward from 14-16 May 2003.
As part of our education /outreach program, we created this original workshop as a profound, manipulative, realistic exercise combining theory and practice. Its intent was to arrive at meaningful science, making physical oceanography vibrant at the secondary level. It is ambitious since it does require major logistics- travel, housing, supplies, instrumentation, computers, and vessel- but this pilot program went well (with miraculously good weather). And as we later add its teacher guide to the website, it may be an activity energetic teachers and students could undertake repeatedly in their own coastal communities over the course of a year. This valuable data would be of genuine interest to physical oceanographers in our group.
The workshop was based at the University of Alaska/Fairbanks' Seward Marine Center. It was ideal having a supportive staff, a library for the classroom, Internet access, a workshop area and adjacent entrée to the waters of Resurrection Bay. The morning of the first day we covered history, theory and design of drifters, ranging from Eulerian (fixed) to Lagrangian (free to flow) types. Preparing our notebooks for the next day's data, we eschewed academia in the afternoon to sew and construct eight full-size (one meter) Davis drifter drogues. After dinner we finished assembly and tested the systems off the dock to verify tether linkages and ballasting of the floats carrying four-foot fibreglas flagpoles, marker flag and shimmering CD for visual tracking.
May 15 was a stunning day for the tracking of the eleven total drifters we set across the 6-km wide middle section of Resurrection Bay. With no wind, temperatures in the 50s F., and sun, we had our drifters in the water by 9:30 am off of the 48-ft Misty chartered from Kenai Fjords Tours. Six positions across the Bay started our location measurements obtained from a hand-held GPS. Three initial positions also had ten-meter deep drogues compared to the normal one-meter depth. And two positions had half-size drogues. Thus, besides learning more about the Bay's circulation, we examined the effects of drogue size and depth. For the remainder of the day we motored back and forth across the Bay marking positions of the drifters about every 40 minutes. For most drifters we recorded eleven locations spanning a flood, high tide and ebb cycle. We also monitored and recorded wind speed and direction with compass and anemometer.
The third and final day of the workshop we reviewed latitude and longitude and then plotted onto chart copies positions of each drifter stage to create individual drifter tracks. Overall direction, distance and speed traveled were then calculated . Posting this graphic data for all to share, we discussed the observations and began an analysis of them. Naturally, it led to new considerations: effects of tides, bathymetry, river run-off and ship traffic. Student calculations were then compared to a Matlab program using an Excel spreadsheet data file that performed similar calculations and plotted them onto an areal basemap. Speeds ranged from .008 m/s to .249 m/s; winds from calm to 5 m/s; and the tidal range was 13.3 feet during the full moon specially arranged for the workshop!
Preliminary results suggest the half-size drifters work as well as the regular size ones. The deeper, ten-meter drogues behaved differently than the regular one-meter ones, moving more slowly. The least expected finding was that most drifters moved in directions opposite that of the tides. In other words, when the tide was flooding, they moved out, and when the tide was ebbing, they flowed in. Wind forcing this behavior seems unlikely because the timing doesn't correlate. Perhaps it is related to river-runoff and that there is a low-density surface layer flowing out. The conventional wisdom that the fjord flow is dominated by tidal circulation may still be true, but for depths greater than those we measured.
This project was funded by NASA Award # NAG13-02042.