Predicting the Loop Current dynamics combining altimetry and deep flow measurements through the Yucatan Channel

Abstract

The Loop Current is the main mesoscale feature of the Gulf of Mexico oceanic circulation. With peak velocities above 1.5 m s–1, the Loop Current and its mesoscale eddies are of interest to fisheries, hurricane prediction and of special concern for the security of oil rig operations in the Gulf of Mexico, and therefore understanding their predictability is not only of scientific interest but also a major environmental security issue. Combining altimetric data and an eddy detection algorithm with 8 years of deep flow measurements through the Yucatan Channel, we developed a predictive model for the Loop Current extension in the following month that explains 74% of its variability. We also show that 4 clusters of velocity anomalies in the Yucatan Channel represent the Loop Current dynamics. A dipole with positive and negative anomalies towards the western side of the Channel represents the growing and retracted phases respectively, and two tripole shape clusters represent the transition phases, the one with negative anomalies in the center associated with 50% of the eddy separation events. The transition between these clusters is not equally probable, therefore adding predictability. Finally, we show that eddy separation probability begins when the Loop Current extends over 1800 km (~27.2°N), and over 2200 km of extension, eddy detachment and reattachment is more frequent than separation. These results represent a step forward towards having the best possible operational Loop Current forecast in the near future, incorporating near real-time data transmission of deep flow measurements and high resolution altimetric data.

Haline Tolerance of Stomatopod (Crustacea) Larvae and Pelagic Dispersal of Two Common Species in the Western Atlantic

“…The high self-recruitment value (16.4%) in the Corpus Christi site ( 19) could be due to inner currents, which are associated with strong southeasterly winds, frontal passages, and changes in the flow direction (Tissot & Dell, 2016). Despite the great distance that separates the Yucatan and Florida peninsulas, Isla Mujeres and Cozumel (sites 25 and 26) feed the Florida Keys (sites 7-9) and the eastern coast of Florida (sites 4-6), because of the influence of the Loop Current, which can reach velocities above 1.5 m s 1 (Manta et al, 2023). Isla Mujeres and Cozumel are considered "sources" of larvae for the southeastern U.S. As in the case of S. empusa, in the western shelf of the Gulf of Mexico (sites 20-23), there was a high level of potential interconnectivity due to changes in the flow direction at seasonal and synoptic time scales (Allende-Arandía et al, 2016;Zavala-Hidalgo et al, 2003).…”