Influence of Stratification and Yucatan Current Transport on the Loop Current Eddy Shedding Process

The effects of stratification and Yucatan Current (YC) transport on the dynamics of the Loop Current (LC) and Loop Current Eddies (LCEs) are studied using a primitive equation, 21/2 nonhomogeneous layered model, which reproduces the main dynamical features of the upper ocean circulation in the Gulf of Mexico (GoM). The analysis considers the observed variations in stratification and YC transport, and their expected changes due to climate change. The study is based on a set of long-term simulations considering the combination of seven stratification configurations with seven transport configurations resulting in 49 cases. The LCE shedding period and diameter (LCE metrics) and kinetic energy, eddy kinetic energy, available potential energy, eddy available potential energy, and the energy Burger number (energy metrics) are analyzed. The stratification and transport contribute to the current and future LC and LCE variability, with their dynamics being more sensitive to transport variations than to stratification variations. The LCE detachment is associated with the increase in the mass of the LC and its available potential energy budget, which is a primary determinant for the LC and LCE dynamics and a condition for eddy shedding. For the expected changes due to climate change, the LCE response is contrary: larger stratification causes increments in the LCE metrics and energy metrics, except the energy Burger number that decreases; conversely, smaller transport causes the opposite response. A combined occurrence of increased stratification and reduced transport, as expected with climate change, causes decrements in the LCE metrics and energy in the GoM.

Automated summary

The study examines the effects of stratification and Yucatan Current transport on the dynamics of the Loop Current and Loop Current Eddies, finding the dynamics to be more sensitive to transport variations than stratification changes. The detachment of Loop Current Eddies is associated with increases in the mass and available potential energy budget of the Loop Current, serving as primary determinants for their dynamics. Expected climate change, including increased stratification and reduced transport, is shown to lead to decrements in the metrics and energy of Loop Current Eddies in the Gulf of Mexico.