SAR Observation of Rip Currents off the Portuguese Coast
Signatures of rip currents can be identified in SAR images and aerial photographs of the near-shore. An area on the Portuguese West coast (bathymetry and wave climate of which are briefly described) was studied. An image corresponding to low wind speed conditions is shown, where a series of rip-like cell features are consistent with rip current morphology. A simple model is presented to explain the signatures, based on wind contrast due to the relative water motion within rip currents. The model is discussed for near-threshold wind conditions of Bragg wave excitation.
KeywordsInternal Wave Synthetic Aperture Radar Significant Wave Height Wave Breaking Synthetic Aperture Radar Image
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- Aagaard T, Masselink G (1999) The surf zone, In: Short AD (ed), Handbook of Beach and Shoreface Morphodynamics, John Wiley & Sons, Chichester, Chapter 4, pp 72-118Google Scholar
- Da Silva JCB, Sancho F, Quaresma L (2006) Observation of Rip Currents by Synthetic Aperture Radar. Proceedings of SEASAR 2006, Advances in SAR Oceanography from ENVISAT and ERS missions, ESA publication SP-613, Frascati, ItalyGoogle Scholar
- Gomes F, Bessa Pacheco M, Jorge da Silva A, Silva R, Rusu E (2005) A Utilização dos SIG na estimativa da corrente de deriva litoral (Aplicação à costa oeste de Portugal continental entre a Figueira da Foz e a Nazaré), Instituto Hidrográfico, internal manuscript with pp 9 in PortugueseGoogle Scholar
- Hasselmann K (1968) Weak-interaction theory of ocean waves. In: Holt M (ed) Basic Developments in Fluid Dynamics, vol 2. Academic Press, San Diego, pp 117-182Google Scholar
- Holt B (2004) SAR imaging of the ocean surface, Chapter 2. In: Jackson C, Apel J (ed) Synthetic Aperture Radar Marine User´s Manual. U.S. Department of Commerce and NOAA, Washington DC, pp 25-79Google Scholar
- Oliveira F, Oliveira T, Silva R, Larangeiro S (2004) Dinâmica sedimentar do trecho litoral Praia da Vieira - Praia Velha. VII Congresso da Água, Lisboa, Portugal, cd-rom. pp 15-30, in PortugueseGoogle Scholar
- Short AD, Hogan CL (1994) Rip currents and beach hazards, their impact on public safety and implications for coastal management. In: Finkl CW (ed) Coastal Hazards, Journal of Coastal Research, Special Issue 12. pp 197-209Google Scholar
- Silva FS (2006) Rip Currents Identification with Synthetic Aperture Radar. Lic. Dissertation Thesis, Faculdade de Ciências do Mar e do Ambiente, University of Algarve, Faro. pp 73, in PortugueseGoogle Scholar
- Smith JM (1999) Wave breaking on an opposing current. Coastal Engineering Technical Note CETN IV-17. U.S. Army Engineer Research and Development Center, Vicksburg, MS, pp 9Google Scholar
- Wackerman CC, Clemente-Colón P (2004) Wave Refraction, Breaking and Other Near-Shore Processes. In: Jackson C, Apel J (ed) Synthetic Aperture Radar Marine User’s Manual. U.S. Department of Commerce and NOAA, Washington DC, pp 171-187Google Scholar