Impacts of Ocean Heat and Moisture Fluxes on Extratropical Cyclone Development in the South Atlantic

ABSTRACT Extratropical cyclones are meteorological systems that significantly influence South America's climate through complex interactions between contrasting air masses and ocean–atmosphere dynamics. This study investigates the role of ocean heat fluxes in the formation and intensification of extratropical cyclones over the South Atlantic. We analysed latent and sensible heat and humidity exchanges between the atmosphere and ocean throughout the life cycle of six case studies, including three intense and three explosive cyclones offshore the coast of South America. Data from the CFSR/CFSv2 reanalysis provided parameters such as latent and sensible heat fluxes, specific humidity, zonal and meridional wind components and sea surface temperature (SST) at 6‐h intervals. The results indicate that latent heat flux associated with SST plays a fundamental role in baroclinic development, while sensible heat fluxes have a secondary role affecting the cyclones' deepening rates. Specific humidity in the warm sector was a crucial factor in the intensification of all the cases studied. As the cyclones dissipate, a weakening of the system is observed, accompanied by a decrease in heat fluxes. This study enhances our understanding of the oceanic influences on extratropical cyclones, improving the ability to monitor and forecast these impactful weather systems.