INVESTIGADORES
ISLA Federico Ignacio
congresos y reuniones científicas
Título:
Coastal-dune bodies recognised by SAR images
Autor/es:
ISLA, F; CORTIZO, L
Lugar:
P. Madryn
Reunión:
Congreso; XIV RAS; 2014
Institución organizadora:
AAS
Resumen:
SAR (Synthetic Aperture Radar) images were conceived to monitor areas where passive remote sensing
did not apply. The European Remote Sensing Satellites (ERS 1 and 2) were planned with specific periods for
monitoring sea-ice contacts. However, band C (5.6 cm) can only penetrate clouds and fogs (Purkis and Klemas,
2011). Polarimetric techniques were applied to deal with different kind of forests and crops. The application of
longer bands has been envisaged as a promising tool for sedimentologic purposes (Henderson and Lewis, 1998).
Band L (23 cm) were applied satisfactorily to survey ground-water flows beneath sand deserts of uniform grain
sizes. Images of ?radar rivers? have been reported from the Sahara, Lybia, China, Mojave, Yuma, Kara-Kum and
Israel deserts (Abdelsalam et al., 2000). Performances depend on grain size, subsurface water content, and the
dielectric constant of the sand (Daniels et al., 2003).
Some of these techniques have been applied to coastal barriers, although they are more subject to
groundwater variations, and their bedforms can change in relation to dry-sand availability and wind variations at
the coastal area (Cortizo and Isla 2007, 2012). In forested or urbanised areas the diffuse reflection (also known
as volume reflection) or the double-bounce effects should be considered (Fig.1). The penetration in sand
diminishes with the rise of the water table.
The brightness due to a high content in quartz can play against the application of images in the visible
spectra (Fig.2A). The L band is a better choice to define dune bodies, or the scars of the migration of parabolic
dunes (Fig.2B). The scars of transverse dunes of Mar Chiquita highlights profiles of the nucleus with large-scale
crossbeds dipping to the north (Fig. 2 C and D).