Seasonal variability of the potential vorticity in the Lofoten vortex

Abstract

The anticyclonic quasi-permanent Lofoten vortex is a strong dynamic formation in the center of the Lofoten Basin in the Norwegian Sea. We used the oceanic reanalysis data GLORYS12V1. We analyzed a seasonal distribution of the relative and potential vorticity, as well as the orbital velocities and the potential density in the Lofoten vortex. The main points of the potential vorticity calculating are considered. The values of the Lofoten vortex volume, the horizontal dimension (the diameter) as well as the vertical scale for the period from 2000 to 2019 are obtained, as well as the method for estimates of these characteristics is described in detail. It was shown that the intensification of the vortex occurs in the summer, and its relaxation -- in the winter.