An Oil Fate Model for Shallow-Waters

Abstract

We introduce a model for the dynamics of oil in suspension, appropriate for shallow waters, including the nearshore environment. This model is capable of oil mass conservation and does so by evolving the oil on the sea surface as well as the oil in the subsurface. The shallower portion of the continental shelf poses compounding unique modeling challenges. Many of these relate to the complex nature of advection and dispersion of oil in an environment in which wind, waves, as well as currents all play a role, as does the complex bathymetry and the nearshore geography. In this study we present an overview of the model as well as derive the most fundamental of processes, namely, the shallow water advectiion and dispersion processes. With regard to this basic transport, we superate several fundamental challenges associated with creating a transport model for oil and other buoyant pollutants, capable of capturing the dynamics at the large spatio-temporal scales demanded by environmental and hazard mitigation studies. Some of the strategies are related to dimension reduction and upscaling, and leave discussion of these to companion papers. Here we focus on wave-filtering, ensemble and depth-averaging. Integral to the model is the proposal of an ocean dynamics model that is consistent with the transport. This ocean J. Mar. Sci. Eng. 2015, 3 1505 dynamics model is detailed here. The ocean/oil transport model is applied to a couple of physically-inspired oil-spill problems in demonstrate its specialized capabilities.

Surface currents in operational oceanography: Key applications, mechanisms, and methods

“…Oil spills can be modelled as Eulerian fields by solving the advection-diffusion equations (e.g. Sobey et al 1997;Restrepo et al 2015) or, more commonly, as Lagrangian particles (e.g. Daniel et al 2003;De Dominicis et al 2016;Röhrs et al 2018a).…”

The Impact of Entrained Air on Wave Dissipation

“…diffusion, which includes the shrinking of bubble radius during their lifetime, see Merlivat and Memerly (1983)), the production of bubbles by rain and a sink term that captures the loss of air bubbles bursting at the surface or dispersed by oceanic turbulence. Solutions of the advection-diffusion equation necessitate specification of the velocity and the dispersion, generating non-stationary descriptions that might also include mixing due to wave turbulence (see Restrepo et al (2015); Moghimi et al (2018)).…”

“…The residence time of small air bubbles can be longer than the wave time scale because viscous effects will be comparable to buoyant forces on the bubbles. However, the residence time of larger bubbles may be long as well due to intense stirring (see Tkalich and Chan (2002); Restrepo et al (2015); Moghimi et al (2018)). For a specific application we zoom on the presence of air bubbles in the thin upper layer of the ocean.…”

Dimension Reduction for Systems with Slow Relaxation

“…Our interest in capturing such weathering dynamics arose from work developing a model for oil spill transport in the ocean [50,49,43]. Crude oil is made up of hundreds, even thousands of different chemical compounds.…”