A Model Analysis for the Design and Deployment of an Eulerian Sediment Trap Mooring Array in a Western Boundary Upwelling System from Southeast Brazil

This work addresses the design and configuration of a Eulerian sediment trap mooring array, which was deployed at the shelf edge (zm ≈ 140 m) 80 km off Cabo Frio, SE- Brazil (23° S). The site was subject to interplay between the Tropical Waters (TW) of the Brazil Current (BC), intrusions from the So...

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Bibliographic Details
Published in:	Anais da Academia Brasileira de Ciências Vol. 86; no. 2; pp. 589 - 600
Main Authors:	Mendoza, Ursula, Candella, Rogério N, Assad, Luiz P F, Castillo, Federico V, Azevedo, Laura, Knoppers, Bastiaan A, Albuquerque, Ana Luiza S
Format:	Journal Article
Language:	English
Published:	Brazil Academia Brasileira de Ciências 01-06-2014
Subjects:	armadilhas de sedimentação desenho eficiência de captura linha de fundeio MULTIDISCIPLINARY SCIENCES ressurgência de Cabo Frio SE-Brasil Cabo Frio upwelling trap efficiency design linha de fundeio sediment traps SE-Brazil ressurgência de Cabo Frio armadilhas de sedimentação mooring array eficiência de captura SE-Brasil desenho
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Summary:	This work addresses the design and configuration of a Eulerian sediment trap mooring array, which was deployed at the shelf edge (zm ≈ 140 m) 80 km off Cabo Frio, SE- Brazil (23° S). The site was subject to interplay between the Tropical Waters (TW) of the Brazil Current (BC), intrusions from the South Atlantic Central Waters (SACW), which are the source of upwelling in the region, and other oceanographic processes. Detailed computations were used to optimize the total weight, buoyancy balance, and maximum acceptable tilt to avoid hydrodynamic bias in the trapping efficiency and array adaptation to the local oceanographic conditions with the assistance of Matlab and Muringa programs and Modular Ocean Model 4.0 (MOM; i.e., to assert the vertical distribution of the meridional current component). The velocity range of the current component was determined by short term measurements to be between 0.1 and 0.5 m/s. Projections led to a resulting minimum anchor weight of 456 kg. The necessary line tension was ascertained by using the appropriate distribution of a series of buoys along the array, which finally attained a high vertical load of 350 kg because of the attached oceanographic equipment. Additional flotation devices resulted in a stable mooring array as reflected by their low calculated tilt (2.6° ± 0.6°). A low drag of 16 N was computed for the maximum surface current velocity of 0.5 m/s. The Reynolds number values ranged from 4 × 104 to 2 × 105 and a cone-trap aspect ratio of 1.75 was used to assess the trap sampling efficiency upon exposure to different current velocities.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0001-3765 1678-2690 1678-2690 0001-3765
DOI:	10.1590/0001-37652014107112