Contrasting hydrographic signatures of two long-lived anticyclonic eddies formed under the influence of the Mexican Coastal Current

Authors:
Preprint
Publisher website
Google Scholar
Abstract
Mesoscale eddies influence hydrography and cross-shore exchange in regions where coastal currents and water masses converge. In the Tropical Pacific off Mexico, Cabo Corrientes is a recurrent source of long-lived anticyclones, but their hydrographic evolution and surface connectivity remain insufficiently understood. We combine satellite altimetry, sea surface temperature and salinity, 4035 quality-controlled Argo profiles, and the Mesoscale Eddy Trajectories Atlas to characterize regional anticyclones and compare two eddies formed in September 2014 and 2016. Surface advective nonlinearity and backward OpenDrift simulations provide complementary diagnostics of retention potential and possible source pathways. Of 632 anticyclones lasting at least 60 days during 1993–2022, 42 persisted for at least 210 days, eight originated north close of Cabo Corrientes. Their formation clustered in summer and early autumn, and rotational velocities generally exceeded translation speeds during much of their westward propagation. The 2014 eddy developed under a stronger, broader, and more persistent Mexican Coastal Current and exhibited a warm, fresh upper layer with a distinct Tropical Surface Water signature. The 2016 eddy developed under a weaker, more intermittent coastal current and showed greater California Current Water influence. On 1 September, their week of generation, 88% and 17% of the backtracked particles lay within the respective low-salinity regions, consistent with contrasting surface connectivity. These cases indicate that eddies originating in the same region and season can develop different hydrographic signatures associated with coastal-current variability and water-mass availability, with implications for the offshore redistribution of upper-ocean properties.

This publication has 24 references indexed in Scilit: