The Energy Decay of Warm‐Core Eddies in the Gulf of Mexico

The Gulf of Mexico (GoM) is home to some of the most energetic eddies in the ocean. Warm‐core rings detach from the Loop‐Current and drift through the basin, transporting large amounts of heat and salt. These eddies, known as Loop Current rings (LCRs) have a crucial role in the GoM's dynamics and in the weather of the eastern US, and this role is largely conditioned by their longevity and decay properties. Here, we use an empirical method to estimate the energy evolution of all LCRs detached since 1993. We found that, contrary to the commonly accepted idea that LCRs conserve their energy as they drift through the GoM and decay suddenly against the western platform, LCRs' energy decay is faster in the eastern basin, and they typically lose three‐quarter of their energy before encountering the continental shelf. We also show that wind‐current feedback contributes to the energy decay and conversion. Plain Language Summary Ocean eddies can be long‐lived and carry large amounts of heat and salt across ocean basins and marginal seas. This is the case of Loop Current rings (LCRs), which are large warm‐core eddies drifting through the Gulf of Mexico (GoM). Understanding how these eddies lose their energy is key to understand their longevity and transport properties. Here, we use a previously validated empirical method based on in situ observations to estimate the time evolution of LCRs energy using satellite observations. We show that LCRs decay continuously during their life cycle, contrary to the previously accepted idea that they decay when collapsing against the western GoM's continental shelf. LCRs typically lose three‐quarter of their energy before reaching any topographic obstacle. Using wind observations, we also show that wind‐current interactions are key to the energy loss of these eddies. Key Points Time evolution of the energy of warm‐core rings in the Gulf of Mexico is assessed using empirical methods and satellite altimetry The vast majority of mechanical energy (kinetic plus available potential) is lost early in the eddies’ life cycles, far from the western boundary Wind‐current feed back effects play an important role in energy conversion and decay