Abstract:

297 near-surface CODE-type ocean drifters (drogued at a depth of one meter) and 10 flat surface drifters (consisting of GPS-equipped and weighted otter boxes), tracked in real-time using SPOT GPS units, were launched in the northern Gulf of Mexico near DeSoto Canyon in July 2012 as part of the CARTHE Grand Lagrangian Deployment (GLAD) experiment. Most of these drifters were launched in nested triplets (separated by roughly 100 m, resp. 500 m, at launch) in an attempt to measure multi-scale near surface dispersion. No temperature or salinity sensors were attached to these drifters. This dataset contains the raw reported positions over the period July 20, 2012 through January 23, 2013. Please note that some of the drifters were picked up by boaters and redeployed during this period, so that not all trajectories reflect ocean currents in their entirety. This dataset was created by the Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE). This research was made possible by a grant from BP/The Gulf of Mexico Research Initiative.

Suggested Citation:

Tamay Özgökmen. 2016. Grand Lagrangian Deployment GLAD experiment CODE-style and flat surface drifter trajectories (raw), northern Gulf of Mexico near DeSoto Canyon, July 2012 - January 2013. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7086388

Purpose:

CODE-style drifters were launched nearly simultaneously in nested triangles (100 m and 500 m separations) to measure near-surface relative dispersion over scales ranging from 100 m to 100 km. In addition, ten flat surface drifters were launched alongside some of the CODE-style drifters to investigate the role of drifter design in capturing ocean currents.

Data Parameters and Units:

Column 1: drifter ID string (like CARTHE_XXX, XXX=3 digit integer) Column 2: date (yyyy-mm-dd) Column 3: time (HH:MM) Column 4: longitude (decimal degrees) Column 5: latitude (decimal degrees)

Methods:

Drifter positions were reported in real-time roughly every five minutes via the Globalstar satellite network. Positions reported by the SPOT handheld GPS units inside each drifter were nominally accurate to within seven meters. Occasionally, position errors much larger than this nominal value are found. These may be due to errors in GPS baselines (due to poor satellite reception), data dropout, and, in some cases, drifters that were picked up by small boats.

Instruments:

CODE II drifter body with SPOT Satellite GPS Messenger and Otter Boxes with weights and SPOT Satellite GPS Messenger

Individual Files: