The response of sound scatterers to El Nino- and La Nina-like oceanographic regimes in the southeastern Atlantic

• Type: Article in International Scientific Journal
• Date: 2009

Authors

Marek Ostrowski (Author) Other; Jose C B da Silva (Author) Other; Bomba Bazik Sangolay (Author) Other

Journal

Title: ICES Journal of Marine Science

Vol. 66

Pages: 1063-1072

ISSN: 1054-3139

Publisher: Oxford University Press

Indexing

ISI Web of Knowledge - 30 Citations

Scopus - 33 Citations

Scientific classification

FOS: Agrarian Sciences > Agriculture, Forestry, and Fisheries

Other information

Authenticus ID: P-003-HT0

DOI: 10.1093/icesjms/fsp102

Abstract (EN): Oceanographic conditions off Angola alternate seasonally between upwelling in the austral winter and El Nino-like intrusions and downwelling in summer. During winter in regions deeper than 30 m, the water column consists of a top layer of warm, tropical water overlying cold, nutrient-rich, and hypoxic South Atlantic Central Water (SACW). Closer inshore the water becomes well mixed. In the stratified region, acoustic backscatter at 38 kHz matches the oceanographic structure. It is strong in the top layer, but declines sharply in the SACW. During summer, the water column is continuously stratified, and the SACW is absent from the shelf. The backscatter reveals multiple thin layers extending across much of the shelf. The scattering layers are often perturbed by internal waves. The combined evidence from multiple acoustic surveys and the existing synthetic-aperture radar imagery suggests that tidal internal waves are a pervasive phenomenon in Angolan waters.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10