Crater Lake Drifter Test – Preliminary Data Report, 1997

Crater Lake Drifter Test – Preliminary Data Report


 Test dates: 11-13 August 1997

Oregon State University personnel: Jack Barth, Mike Kosro, Stephen Pierce, and Andy Dale

National Park Service Crater Lake Research Team: Scott Girdner, Jeff Milder, and Ashley Gibson

Objectives: Test new Wide Area Differential GPS (WADGPS) surface drifters and examine Crater Lake circulation.

We have implemented WADGPS on a surface drifter. WADGPS is a technique to improve GPS positioning accuracy from +/-100 m to +/- 20 m or better. See Wilson et al. (1996) for technical details. This Crater Lake work was the “full field test” mentioned in the Wilson et al. paper, planned for August 1996 but delayed until August 1997.

T.C. Wilson, J.A. Barth, S.D. Pierce, P.M. Kosro, and B.W. Waldorf, “A Lagrangian drifter with inexpensive wide area differential GPS positioning,” Oceans ’96 MTS/IEEE Conference Proceedings, 2, 851-856, 1996.

Future plans: Plot up wind records (we have these in hand) and interpret drifter motions in terms of simple closed-basin, wind-forced circulation models.

Figure 1. One drifter tracked over 18 hours with a fix every 5 min. Note improvements in positions and speed estimates using WADGPS.