Effect of the North Equatorial Counter Current on the generation and propagation of internal solitary waves off the Amazon shelf (SAR observations)

• Type: Article in International Scientific Journal
• Date: 2016

Authors

J.M. Magalhaes (Author) Other; da Silva, JCB (Author) FCUP; M.C. Buijsman (Author) Other; C.A.E. Garcia (Author) Other

Journal

Title: Ocean Science

Serial No. 1812-0784 Vol. 12 No. 1

Pages: 243-255

ISSN: 1812-0784

Publisher: Copernicus

Indexing

ISI Web of Knowledge - 31 Citations

ISI Web of Science

Scopus - 33 Citations

Scientific classification

CORDIS: Natural sciences > Environmental science > Earth science

Other information

Authenticus ID: P-00K-6R3

DOI: 10.5194/os-12-243-2016

Abstract (EN): Synthetic aperture radar (SAR) imagery from the Amazon shelf break region in the tropical west Atlantic reveals for the first time the two-dimensional horizontal structure of an intense Internal Solitary Wave (ISW) field, whose first surface manifestations are detected several hundred kilometres away from the nearest forcing bathymetry. Composite maps and an energy budget analysis (provided from the Hybrid Coordinate Ocean Model - HYCOM) help to identify two major ISW pathways emanating from the steep slopes of a small promontory (or headland) near 44 degrees W and 0 degrees N, which are seen to extend for over 500 km into the open ocean. Further analysis in the SAR reveals propagation speeds above 3 ms(-1), which are amongst the fastest ever recorded. The main characteristics of the ISWs are further discussed based on a statistical analysis, and seasonal variability is found for one of the ISW sources. This seasonal variability is discussed in light of the North Equatorial Counter Current. The remote appearance of the ISW sea surface manifestations is explained by a late disintegration of the internal tide (IT), which is further investigated based on the SAR data and climatological monthly means (for stratification and currents). Acknowledging the possibility of a late disintegration of the IT may help explain the remote-sensing views of other ISWs in the world's oceans.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13