Analysis of mesoscale frontal zones of the Norwegian Sea based on satellite observations and reanalysis data in May 2011–2020

Abstract

   The aim of this study is to compare the horizontal temperature gradients calculated based on satellite observations and reanalysis data in the area of mesoscale frontal zones’ surface manifestations, both for the entire Norwegian Sea and during the onset of pelagic fish spawning migrations in May from 2011 to 2020.   Using monthly average temperature data from MODIS/Aqua, GHRSST OSTIA, and CMEMS GLORYS12v1, the fields of monthly and decade-long horizontal gradients on the surface of the Norwegian Sea were derived. A comparison was made between the decade-long temperature gradient estimates and their mean climatic values. The majority of the data show surface manifestations of the main frontal zones in the Norwegian Sea. Validation of temperature fields in the area of the Iceland-Faroe Frontal Zone was conducted based on unique in situ observations. It was demonstrated that for the analysis of the frontal zones in the Norwegian Sea, using the temperature fields of GHRSST OSTIA is most preferable. The obtained physico-geographical characteristics of mesoscale frontal zones could be used to assess their relationship with pelagic fish migrations in the Norwegian Sea.