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1. Introduction
The Lagrangian Submesoscale Experiment (LASER) was designed to study near-surface physical processes during winter conditions in the northern Gulf of Mexico (NGoM) as part of the long-term objective of understanding oil dispersion. The study was motivated by the Deepwater Horizon oil spill in 2010, the largest accidental marine oil spill in history. Observations of oil spills show complex patterns-most notably accumulation and transport in small-scale convergence zones-that are not predicted by traditional transport models that assume nondivergent flows (Zhong et al. 2012; Huntley et al. 2015; Haza et al. 2016). Recent progress in the understanding of submesoscale flows (McWilliams 2016) provides a new theoretical basis for these surface convergence regions. To test some of these theories in the field, high-resolution Lagrangian measurements of surface flow are needed, with a large number of drifters capturing scales from tens of kilometers to tens of meters, to resolve both larger-scale nondivergent and smaller-scale divergent features. Toward this goal, the new Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE) surface drifter was designed (Novelli et al. 2017; Lumpkin et al. 2017). The environmentally friendly design used injection-molded biodegradable plastic components that could be inexpensively produced, easily assembled, and hand deployed (Fig. 1a). The drifter was extensively tested to minimize wave rectification and wind slip and to verify that this design accurately tracked the average horizontal current in the upper 60 cm. More than 1000 units were deployed during LASER in January through February 2016 in the DeSoto Canyon region of the NGoM.
More than 1000 drifters were released during this experiment. The experiment was in part composed of three large deployments of about 300 drifters each, including two in tightly packed configurations on the continental slope of the NGoM.
Unusually strong storms occurred during LASER as the result of the 2016 El Niño, with the most intense episodes occurring 22 and 27 January; 5, 9, 15, and 24 February; and 9 March. In particular, major storms occurred 1-2 days after...