Modeling Weakly Buoyant Particles in a Regional Ocean

Weiyuan DONG1, Junhong Liang1, Changming Dong2, Dubravko Justic3, Daniel Holstein4, Robert D Hetland5 and Daijiro Kobashi5, (1)Louisiana State University, Baton Rouge, LA, United States, (2)University of California, Department of Atmospheric and Oceanic Sciences, Los Angeles, United States, (3)Louisiana State University, Oceanography and Coastal Sciences, Baton Rouge, LA, United States, (4)Duke Marine Laboratory, Marine Science and Conservation Division, Beaufort, NC, United States, (5)Texas A&M University, College Station, TX, United States
The pathway and dispersion of weakly buoyant particles including microplastics and oil droplets are important for the prediction of the fate of those particles and the design of mitigation strategies. Albeit with their buoyancy, those particles are subducted into the ocean surface boundary layer by turbulent flows. We implement a parameterization for horizontal velocity of weakly buoyant particles in ocean surface boundary layer (Liang et al. 2018, Horizontal dispersion of buoyant materials in the ocean surface boundary layer, Journal of Physical Oceanography, 48, 2103-2125) into the Lagrangian TRANSport model (LTRANS) (North et al. 2011) and test it with solutions for a regional ocean. We show that particles of different buoyant rising speeds move and spread at different rates and in different directions.