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Abstract
Eastern Boundary Current Systems (EBCS) are highly productive ecosystems due to upwelling that brings cold, nutrient-rich waters to the surface along the coasts. The distribution of the upwelled water can be influenced by several physical processes in these regions, which can impact biological activity. Satellite-derived measurements of particulate organic carbon (POC) are used as a tracer of coastal water to quantify the eddy-induced offshore enrichment of POC in the California Current System (CCS). Cyclonic eddies located offshore that were generated near the coast in general contain higher POC concentrations in their interior than cyclones of similar size generated locally offshore. This analysis was expanded to the other major EBCS, revealing regions within each EBCS where the offshore transport of POC by eddies is most important. These regions are often associated with upwelling jet separation, which helps produce favorable conditions for eddy-induced transport of coastal water to occur. These results provide large-scale observational-based evidence that nonlinear cyclonic eddies can trap and transport coastal water offshore. This mechanism can substantially widen the area influenced by highly productive upwelled waters in the EBCS and influence the marine ecosystems. EBCS also feature sea surface temperature (SST) fronts that form between cold, upwelled water and warmer offshore water. Thirty-seven years of satellite SST data are used to detect SST fronts in the two eastern Pacific Ocean EBCS to investigate the interannual variability of fronts due to the El Niño-Southern Oscillation (ENSO). Results indicate that frontal activity generally decreases during El Niño events and increases during La Niña events along most of the coastline in both regions. Satellite measurements of wind stress and sea level anomaly were utilized to investigate the oceanic and atmospheric forcing mechanisms associated with ENSO and how they affect frontal activity. This analysis revealed regions in both EBCS where one mechanism is likely dominant and regions that are influenced by both forcing mechanisms. Overall, this dissertation expands our understanding of the physical dynamics associated with upwelling in the EBCS and how they may influence the marine ecosystems.