Table of Contents
International Journal of Oceanography
Volume 2013 (2013), Article ID 403259, 11 pages
http://dx.doi.org/10.1155/2013/403259
Research Article

Internal Solitary Waves in the Brazilian SE Continental Shelf: Observations by Synthetic Aperture Radar

Divisão de Sensoriamento Remoto, Instituto Nacional de Pesquisas Espaciais (INPE), CP 515, 12227-010 São José dos Campos, SP, Brazil

Received 23 October 2012; Accepted 25 February 2013

Academic Editor: Robert Frouin

Copyright © 2013 João A. Lorenzzetti and Fabian G. Dias. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We present an analysis of internal solitary waves (ISWs) on the SE Brazilian continental shelf using a set of Envisat/ASAR satellite images. For the 17-month observation period, 467 ISW packets were detected. Most of observed solitons were associated to 4–6  wind. The number of ISW packets shows a seasonal signal with a peak in summer, with higher concentration in the outer shelf in all seasons, followed by midshelf during the summer. Propagation direction of ISWs was predominantly onshore with packets separated by typical internal tide wavelengths (~10–40 km). The highest values of the barotropic tidal forcing F are concentrated at the shelf break between 200 and 500 m isobaths. These characteristics suggest that ISWs are formed from nonlinear disintegration of internal tides generated at the shelf break that propagate shoreward as interfacial internal waves. No significant change in the number of ISWs from spring to neap tides was observed in spite of significant tidal current variation (60%). Even not being a region of strong tides, this study shows that ISWs are a frequent and widespread feature, possibly playing a significant dynamic role, affecting biological production, sediment dispersion, and transport.