A Lagrangian particle model with nesting capability and its application to the modeling of plastics in the Gulf of Mexico
Semester of Graduation
Master of Science (MS)
The Department of Oceanography and Coastal Sciences
In our study, we refined an offline three-dimensional (3D) Lagrangian model named the Larval TRANSport Lagrangian (LTRANS) model and applied it to the Gulf of Mexico (GOM). Previous research that applied the model within the Texas-Louisiana (TXLA) shelf domain, which released plastics to simulate their trajectories and fate, showed that more than 40% of simulated particles did not reach the land boundaries. Some of those particles were assumed to move out of the TXLA domain. In reality, these particles could also re-enter the TXLA domain due to processes such as tidal excursion, mesoscale eddies and inertial oscillation. However, the model could not keep track of the particles re-entering the TXLA domain. To address this problem, the model nesting capacity was added to the LTRANS model to keep track of these returning particles and the nesting model was subsequently applied to 27 release locations in the Gulf of Mexico (GOM). The addition of viscosity and the reduction in particle rising speed increased the average drift distance and drift time of particles, which allowed some particles to reach the Atlantic Ocean, and also enhanced the connection between the Loop Current, the Gulf Stream and the ocean currents in the western side of the GOM and the coastal area of Mexico. Particles released from rivers along the TXLA and Northeast GOM shorelines seldom left the GOM proper and entered the Atlantic Ocean. In contrast, particles released from Mexican rivers would often reach the Atlantic waters, suggesting that there is a strong connection between the ocean currents in the Atlantic Ocean and the coastal waters of Mexico, and that the Loop Current and the Gulf Stream predominantly carry particles entering the Atlantic waters.
dong, weiyuan, "A Lagrangian particle model with nesting capability and its application to the modeling of plastics in the Gulf of Mexico" (2022). LSU Master's Theses. 5702.
Available for download on Saturday, December 28, 2024