Transport and Mixing of Water Masses Across the Southeast Caribbean Ocean Imaged by Seismic Reflection Data

• Main Author: Renzaglia, Joseph
• Format: Text
• Language: unknown
• Published: SMU Scholar 2023
• Subjects: Geophysics and Seismology; North Atlantic
• Online Access: https://scholar.smu.edu/hum_sci_earthsciences_etds/32; https://scholar.smu.edu/context/hum_sci_earthsciences_etds/article/1034/viewcontent/Final_Thesis.pdf

The Caribbean Sea serves as a major pathway for global thermohaline circulation (THC), which is a complex and vital component of the Earth’s climate system, influencing global heat distribution and oceanic circulation. Though relatively stratified, it is the boundary layer that distributes mass and temperature between the surface waters and the deep ocean where we observe various multiscale mixing processes from mesoscale to fine-scale. In regions where bathymetry is shallower and mechanical mixing forces, such as winds and tides, are more dominant, diapycnal diffusivity is typically stronger, driving vertical mixing. This type of mixing occurs at small scales, typically as internal waves break within the internal ocean, making it difficult to quantify and observe. Through the combination of seismic images and oceanographic data, known as seismic oceanography, we can qualitatively and quantitatively observe the variability of the ocean’s internal wave field and its diverse components, which include the turbulent and internal wave subranges from vertical displacement spectra. Exploiting these subranges allows us to quantify vertical mixing behaviors across isopycnal layers, effectively representing the cascade of energy for mixing. Quantitatively constraining these energy components is essential to comprehensively understand the total energy budget of the THC. This research focuses on mapping and quantifying diapycnal diffusivity in the southeastern Caribbean Sea, a region characterized by the convergence of two primary water masses, North Atlantic water (NAW), and South Atlantic water (SAW), as they spill into the Caribbean Sea through the Lesser Antilles passages. This convergence introduces perturbations in temperature, salinity, and nutrients, resulting in the formation of the Caribbean Current. The current’s predominant westward direction, driven by surface winds, is influenced at depth by interactions with deeper water masses and the irregular coastal bathymetry. We utilize five seismic profiles, totaling ...