A gridded surface current product for the Gulf of Mexico from consolidated drifter measurements

Abstract. A large set of historical surface drifter data from the Gulf of Mexico – 3761 trajectories spanning 27 years and more than a dozen data sources – are collected, uniformly processed and quality controlled, and assimilated into a spatially and temporally gridded dataset called GulfFlow. This dataset is available in two versions, with one-quarter degree or one-twelfth degree spatial resolution respectively, both of which have overlapping monthly temporal bins with semimonthly spacing, and extend from the years 1992 through 2019. Together these form a significant resource for studying the circulation and variability in this important region. The uniformly processed historical drifter data interpolated to hourly resolution from all publicly available sources are also distributed in a separate product called GulfDriftersOpen. Forming a mean surface current map by directly bin-averaging the hourly drifter data is found to lead to severe artifacts, a consequence of the extremely inhomogeneous temporal distribution of the drifters. Averaging instead the already monthly-averaged data in GulfFlow avoids these problems, resulting in the highest-resolution map of the mean Gulf of Mexico surface currents yet produced. The consolidated drifter dataset is freely available from https://doi.org/10.5281/zenodo.3985916 (Lilly and Pérez-Brunius, 2020a), while the gridded products are available for noncommercial use at https://doi.org/https://doi.org/10.5281/zenodo.3978793 (Lilly and Pérez-Brunius, 2020b), the latter being freely available for noncommercial use only for reasons discussed herein.