The Xiamen Symposium on Marine Environmental Sciences (XMAS 2025)

Coherent Vortex Structures (CVSs) are spatial and temporal persistent features of any continuous medium. They correspond to vortex formations in geophysics and play a significant role in the dynamics of the atmosphere and ocean. Large vortices, such as cyclones, are the most studied phenomena nowadays. However, mesoscale and submesoscale processes remain in a "gray zone" with limited understanding of their impact on climate. To obtain a reliable climate assessment, invariant criteria for identifying CVSs are necessary. The study proposes to use Rortex criterion (developed for small-scale turbulence) to determine CVSs in the atmospheric numerical modeling data. Rortex criterion was applied to the regional high-resolution historical atmospheric forecast over the North Atlantic NAAD (North Atlantic Atmospheric Downscaling) for the period 1979-2018. 

During the research, we have developed methods to isolate CVSs, determine their boundaries using the DBSCAN algorithm, and automatically track and plot vortex trajectories. This toolkit made it possible to obtain the characteristics of each vortex throughout its life cycle. This opened up the opportunity to access the density of cyclonic and anticyclonic mesoscale structures, as well as to conduct a preliminary clustering of different types of vortices based on their internal thermodynamic characteristics. The data obtained make it possible to estimate the frequency of occurrence, climatology and interannual variability of mesoscale processes in the North Atlantic region.