Defense Date
12-7-2023
Document Type
Thesis
Degree Type
Master of Science
Degree Name
Marine Science
First Advisor
Alexander Soloviev, Ph.D.
Second Advisor
Richard E. Dodge, Ph.D.
Third Advisor
Ye Tao, Ph.D.
Keywords
Glider, Wirewalker, ADCP, CTD, Optics, Florida, Currents, Gulf Stream, Seasonality, Eddies, Richardson Number
Abstract
We deployed a Slocum G3 glider fitted with an acoustic Doppler current profiler (ADCP), a Conductivity-Temperature-Depth sensor (CTD), optics sensor channels, and a propeller on the Southeastern Florida shelf. The ADCP and CTD provide continuous measurements of Northern and Eastern current velocity components, salinity, temperature, and density, throughout the water column in a high-current environment. The optics sensor channels are able to provide measurements of chlorophyll concentrations, colored dissolved organic matter (CDOM), and backscatter particle counts. Additionally, for one of the glider deployments, we deployed a Wirewalker wave-powered profiling platform system also fitted with an ADCP and a CTD in the vicinity of the glider’s area for intercalibration of the devices. As the glider’s velocity profiles are analyzed through time and space we saw evidence of an intermittent southward flow (SWF) opposite to the overlying northward Florida Current (FC) that was previously described by Soloviev et al. (2017). Meandering and strength of this SWF was influenced by the presence or absence of the Gulf Stream close to the shore, persisting in time spans of at least a few hours. Although specific mechanisms that influence the SWF’s behavior are still unknown, our results show that its attachment to the shore along the continental slope was associated with the presence of eddy features in some sort of coupled system with possible implications on turbulent mixing. CTD results show that the SWF appears as either an undercurrent or a countercurrent depending on the strength of the water column stratification. Optical channel results show that the SWF assists in the southwards transport of particulate matter and biological material at depth, with possible implications on nutrient transport and biological activity. Richardson number results for analysis of turbulent flow were inconclusive as to how much turbulence is actually created by the SWF, but it does show evidence of increased turbulent activity at the interface between the SWF and the FC during some deployments. Analysis of the relationship between the northern component of velocity and the eastern component revealed a possible mechanism that would provide the optimal conditions for upwelling events to take place. 23 deployments have been done so far, with more planned for the future. More research is needed to accurately assess the effect the SWF has on velocities and transport of pollution and biological material along and across the shelf against the FC.
ORCID ID
0009-0002-0056-9232
NSUWorks Citation
Alfredo Quezada. 2023. Investigating the Effects of a Southward Flow in the Southeastern Florida Shelf Using Robotic Instruments. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, . (159)
https://nsuworks.nova.edu/hcas_etd_all/159.
Included in
Environmental Indicators and Impact Assessment Commons, Environmental Monitoring Commons, Fluid Dynamics Commons, Oceanography Commons, Other Earth Sciences Commons, Statistical Methodology Commons
Comments
This work has been supported by the ONR Awards N00014-18-1-2835, N00014-21-1-4007, N00014-22-1-2008, N00014-23-1-2270, and N00014-23-1-2746. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the U.S. Navy. The views expressed in this article are those of the author and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, nor the U.S. Government.