Seasonal & inter-annual variability of observed mesoscale eddies in the Caribben Sea

Abstract

Mesoscale eddies are ubiquitous features in the ocean that typically exhibit different prop-erties respect to their surroundings transporting passive tracers such as heat, salt andcarbon, and being relevant structures for the redistribution of energy and mass around allthe oceans. Eddies also play an important role in supplying nutrients to the shelf-slopeand to the upper layers where phytoplankton blooms may result. More than one half of thekinetic energy of the ocean dynamics is contained in the mesoscale, in which eddies arethe major player. In this Thesis the main statistical characteristics of mesoscale eddiesin the Caribbean Sea as well as the seasonal and inter-annual variability in the numberof eddy observations are studied. Since the Caribbean Sea is a semi enclosed basin, alarge part of the transport of nutrients and heat both in the vertical and in the horizontalare to a large extent the result of these structures. Key descriptors of mesoscale eddiesfrom satellite-based sea level anomalies (SLA) such as their lifetime, size and amplitudeare assessed for the period between 1993 and 2016. Moreover, the spatio-temporalvariability in the number of eddy observations is evaluated against the Sea Surface Tem-perature (SST), the surface wind curl and the main climatic index of variability in the area,El Niño Southern Oscillation (ENSO). The ENSO appears to have certain influence atthe inter-annual scale in the number of eddy observations. The above analysis is per-formed by combining a suite of statistical techniques such as the power spectral density,the coupled Singular Value Decomposition, Self-Organizing Maps and the wavelet trans-form. The more accurate knowledge of the main eddy properties, and the spatio-temporalvariability of the number of eddy observations provided in this thesis, contributes to under-stand better their formation and dissipation mechanisms and their preferred trajectories,who have crucial implications on the biogeochemical cycles as well as on some air-seaexchange processes in the Caribbean Sea.