Science Service System

Summary of Proposal OCE2254

TitleInternal wave systems in the tropical and western South Atlantic: from satellite views to local predictability
Investigator da Silva, Jose - University of Porto, Geosciences, Environment and Spatial Planning
Team Members
Prof. Garcia, Carlos - Federal University of Rio Grande (FURG), Instituto de Oceanografia
Professor Saraceno, Martin - University of Buenos Aires, Departamento de Ciencias de la Atmósfera y de los Océanos
Professor Buijsman, Maarten - University of New Orleans, Physics
Professor Calil, Paulo - Federal University of Rio Grande, Institute of Oceanography
SummaryThe general objectives are: 1) to understand the generation mechanisms of the ISWs visible in SAR images on- and off- the Brazilian continental shelf, including the Santos Basin, the tropical Atlantic off the Amazon river and along the Patagonian continental slope; 2) to conceive and implement a propagation model to predict the arrival times of these ISWs to locations of interest (to be determined in 1); 3) and to gather information and insights from satellite remote sensing, that can be used in numerical models of physical-biological interactions at the submesoscale (horizontal scale of O(1-10) km, a vertical scale of O(100) m, and a time scale of O(1) day).The prediction system for the generation, propagation, refraction and arrival times of ISWs on the South American continental margins and off the Amazon shelf break will be supported by specific tasks. In a first phase we will assess and evaluate available datasets, including TerraSAR-X data and in situ measurements. This will be followed by development of a set of Internal Wave Tools (IWTs) for the regional prediction of the internal wave fields based on hydrophysical ocean fields. These tools will be used with fine resolution numerical models (based on the eikonal differential equation and a fast marching method) for forecasting the location and timing of ISWs. In a third phase of the project we will make a division of case studies according to the study regions and in three different categories: generation, propagation, and nonlinear evolution/ interaction. Finally, an interpretation of the major regional trends of the internal wave fields will be delivered, adding modelling perspectives to the image data.This project relies on the new Wide ScanSAR TerraSAR-X mode. This is critical to appreciate the full extent of the wide ISWs crestlengths off the Amazon continental shelf and the full propagation characteristics at the Patagonian shelf break. We are also interested in a small amount of the very high resolution Staring Spotlight (ST) mode to look at mixing events within ISW surface signatures. It has been demonstrated that “boils” of water associated with surface mixing can be seen in infrared images along ISW crests, and we plan to investigate if such events can be detected in TerraSAR-X ST images. This would document mixing events, especially along the Patagonian shelf break. Data requirements thus include the two newly available TerraSAR-X imaging modes. We expect to need 40 new Wide ScanSAR images for each of the three study regions (120 scenes in total), and 10 ST images for each regions (30 in total).Deliveries include an Internal Wave Atlas based on TerraSAR-X images and synergies with other SAR mission products (e.g. ERS, Envisat and Sentinel-1). The Atlas will be available as a Google Earth .kml file. It will include maps of barotropic tide body force based on Baines (1982) model, which will be run using amplitudes and phases extracted from the Ocean Topography Experiment (TOPEX)/Poseidon 7.2 (TPXO7.2) tidal inversion model. For the Santos basin, a regional map with the hotspot locations of the main ISW-ISW interactions’ sites will also be published in .kml format. The results of the project will be presented at international meetings as well as the TerraSAR-X Science meetings. Papers for Journals with high impact factors will be written and published.The funding for this project is provided by National Council for Scientific and Technological Development of the Ministry of Science, Technology and Innovation (CNPq/MCTI), which has granted the PI with a Special Visiting Researcher Fellowship under the Brazilian Scientific Mobility Program "Ciências sem Fronteiras". The projects’ global grant amount is 100,447.44 Euro, which includes funding for image data acquisition as well as travel money for the PI visits to the Federal University of Rio Grande (Brazil) suitable for 9 months. The project has started in February 2014, and is for three years in total.

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