Intercomparisons of five ocean particle tracking software packages

Abstract. Particle tracking is widely utilized to study transport features in a range of physical, chemical, and biological processes in oceanography. In this study, a new offline particle tracking package, Tracker, is introduced and its performance is evaluated in comparison to an online Eulerian dye, one online and three offline particle tracking software packages in a small high-resolution (200 m) model domain and a large coarser (1000 m) model domain. It was found that both particle and dye approaches give similar results across different model resolutions and domains when they were tracking the same water mass, as indicated by similar mean advection pathways and spatial distributions of dye and particles. The flexibility of offline particle tracking and its similarity against online dye and particle tracking make it a useful tool to complement existing ocean circulation models. Lastly, the new Tracker was shown to be a reliable particle tracking package to complement the Regional Ocean Modeling System (ROMS), and tradeoffs of performance, modifiability, and ease of use that can influence the choice of which package to use are discussed.