Gridded model trajectories from SOCIB's Western Mediterranean Operational Forecasting System, launched on hourly positions from 2018-06-01 to 2018-06-03

Synthetic particles trajectories were initialized on the model grid, spaced 0.0038 degrees in latitude and 0.0048 degrees in longitude, yielding roughly 400-m resolution. The grid is 527 (longitude) x 462 (latitude) and roughly covers part of the Alboran Sea; 213934 of these locations have valid trajectories, while the rest are launch grid points on land. Particles were advected with a fourth order Runge-Kutta scheme with a 10-minute time step. The position vector was augmented with the strain tensor components. The underlying velocity field was taken from the surface layer of the 3-hourly archive of a 1-month free run of the Western Mediterranean Operational Forecasting System, an implementation of the Regional Ocean Modeling System (ROMS) maintained by SOCIB. For the computation, archived velocities were linearly interpolated. Positions and strain tensor components are stored hourly, along with flags indicating when synthetic particles have reached either the model coast or an open boundary cell in the model. This dataset supports the publication “Conditions for Reliable Divergence Estimates from Drifter Triplets” by Huntley et al (2022). The dataset contains the modeled drifter trajectories and a list of the observed CALYPSO drifter trajectories used in the work to ascertain the usefulness of the results. The full set of CALYPSO drifters can be found at https://www.aoml.noaa.gov/phod/gdp/index.php.