Application of Aerial Video Images for Lagrangian Tracer Studies in Maritime and Estuarine Port Zones

• Published in: Journal of coastal research Vol. SI; no. 56; pp. 787 - 791
• Main Authors: Bezerra, M.O., Akel, A.R., Araújo, T.R.C., Krelling, A.P.M., Redondo, J.M.
• Format: Journal Article
• Language: English
• Published: Fort Lauderdale Coastal Education & Research Foundation (CERF) 01-01-2009; Allen Press Inc
• Subjects: Aerials; Buoys; Coastal; Coastal Hazards and Pollution; Coasts; Contaminants; Diffusion coefficient; Dispersions; Environmental studies; Experiments; Floods; Lagrangian function; Milk; Ocean currents; Oil spills; Ports; Studies; Tides; Tracers; Velocity; Waves; Wind; Wind velocity; Brazil; ASW, Brazil, Ceara
• ISSN: 0749-0208; 1551-5036

Lagrangian tracer dispersion studies were conducted through the analysis of aerial video images of the Mucuripe-Fortaleza (Ceará, Brazil) sea port and the area surrounding the fluvial ports of Miramar and Soure (Pará-Brazil). The objective was to verify the dispersion of Lagrangian tracers according to physical parameters such as wind, currents and waves in order to understand regional dynamics and corroborate studies on environmental sensitivity to oil spills and the recovery of contaminated areas. The studies consisted of obtaining video images of tracer movements on the water surface. Milk was used as the tracer, with 40 liters of milk launched at each starting point. The experiments were conducted at high, ebb, low and rising tides. A physical profile (water chemistry and data on current, tides, waves, and wind) was carried out simultaneously to each discharge. Turbulent diffusivity values (K) were measured experimentally using Einstein's Diffusion Law in the following way $K=\frac{1}{2}\frac{dD^{2}}{dt}=V.D$, where K is the eddy diffusivity, V is the velocity at which the tracer disperses and D is the overall size of the tracer. The main results reveal that at the port of Mucuripe in Ceará, the wind has a strong influence on dispersion, whereas in Pará, the tracers tended to follow the direction of the tide, and in the absence of any significant current, spills followed the direction of the wind.