Overview
Tracking the movement of large floating marine carcasses is valuable for understanding stranding events. This study used the Lagrangian particle tracking (LPT) module within the EFDC+ hydrodynamic model to track such movements, conducting a sensitivity analysis and calibration against data from six GPS-tagged drifters collected by NOAA in April 2017.
Model Setup
The analyses investigated the influence of specific parameters — notably wind drag and the number of vertical layers in the model. The wind drag coefficients A and B, which are the slope and y-intercept of the linear equation describing the overall drag coefficient as a function of wind velocity, were varied to assess their relative impact. Results were compared using the Skill Score statistic.
Key Findings
Adding wind drag to the LPT was a pivotal alteration, increasing the Skill Score from 0.23 to 0.47. Of the two wind drag coefficients, A had a larger impact on model predictions than B. The transition from a 2D to a 3D model had a more significant impact on results than increasing the number of vertical layers within the 3D configuration. However, the improvement in accuracy from moving to 3D was not large enough to justify the additional computational demands for long-period simulations spanning several years — an important consideration for LPT modeling in the Mississippi Sound area.