Rapid dissipation of a Loop Current eddy due to interaction with a severe Gulf of Mexico hurricane

Loop Current Eddies (LCEs) are warm-core, anticyclonic rings that shed from the Loop Current and migrate westward providing kinetic and potential energy to the Gulf of Mexico (GoM). Typically, LCEs dissipate through interaction with the western shelf slope, other mesoscale eddies, and diapycnal mixing. Here, we explore a case where a LCE, Eddy Poseidon, encountered Hurricane Harvey in the northwest GoM in August 2017 causing its rapid dissipation. This interaction significantly reduced Poseidon’s areal extent, dynamic height, heat content, and kinetic energy. Using in situ observations and numerical model output, we explore Poseidon’s dissipation and show it was caused by a combination of processes. A rigorous cold wake formed along Poseidon’s east, strong hurricane-induced surface currents transported shelf water towards the eddy on its north and west sides, and heat was lost throughout the water column from Poseidon’s southern edge. Horizontal advection was greatest at the surface and decreased with depth—27% of heat lost from Poseidon occurred in the top 100 m and 47% from the top 200 m.