Laboratory simulation of ocean surface circulation in the Canary Islands area: Applications to pollutant transport prediction

Abstract

The adverse effects of spilling pollutants in water have focused attention on thebehaviour of contaminants at sea, especially at coastal and shelf seas due to theirkey role for a wide range of human activities and interest. In particular, when oilis spilled in the marine environment, a primary concern is where the oil will go.Oil spill models suitable for use in oil spill response and contingency planning,providing rapid predictions of the movement of spilled oil, require an adequateknowledge about the ocean surface circulation in the area around the oil spilllaunch site to estimate the probabilities of contacting portions of a coastline.Unfortunately, field measurement programs are so expensive and timeconsuming that usually the existing information is scant and sparse. Numericaland physical models represent an alternative to alleviate this drawback.This paper presents preliminary results of ocean circulation in the CanaryIslands area obtained through laboratory simulations. Experiments were carriedout in the SINTEF Coriolis rotating basin, using a simplified topography thatreflects the most relevant morphological aspects of the study area in the upper400 m of the ocean. The tank was filled with water of homogeneous density, insuch a way that the density stratification effects were removed. Therefore, theobserved flow perturbations might be due to the gradients of fluid depths, orvorticity changes, the blocking effects of the islands on the incident flow and thetopographic irregularities of the coastline. Ink and surface drifters were releasedto visualise relevant structures and to estimate the surface flow by tracking the drifter paths under different flow conditions.