104 research outputs found
"Electromagnetic method for measuring glaciers thickness"
No full textComplex permittivities of ice and snow are used as a basis for defining the design parameters of a radar capable of mapping the thickness of a glacier covering the rock mantel which lies above Mont Blanc underground stations
A metric wave radio-acoustic tropospheric sounder
No full textA metric wavelength version of the radio-acoustic sounding system (RASS) at Trino Vercellese, near Turin, Italy, is presented. Evidence is shown of satisfactory soundings in conditions of calm or light winds
"The impact of higher-order Bragg terms on radar sea return"
No full textThe possibility that radar sea return observed using a Ku band fan beam Doppler airborne scatterometer flown over crude oil artificial spills might have been back-scattered via the second-order Bragg interaction is surmised. An attempt is made to justify the absence of the first-order Bragg term
Sea surface slicks measured by SAR
No full textThe Synthetic Aperture Radar (SAR) system capability to detect and characterise marine surface slicks was tested during the SAR-580 experiment in the northern Adriatic Sea, offshore the Venice coast, in October 1990. Two small artificial slicks of oleyl alcohol were produced in an area around the oceanographic platform of the Italian National Research Council (CNR). The oleyl alcohol produces a damping of the sea centimetric waves, which has been measured by an airborne two band (C and X) SAR, by a tower based 3 band (L, S and C) scatterometer and by a wave gauge, installed on board the platform, which measures the instantaneous sea surface elevation in the range from gravity up to capillary waves. The good agreement among measures proves that multi-frequency SAR is able to detect and characterise sea surface films. Slicks in SAR images taken during SIR-C/X-SAR mission in 1994 have been analysed on the basis of these results and L-band measurements of spatial attenuation near the borders of the slicks have been done, in order to test the slicks detectability using single-band SAR images
Slicks detected by measuring damping effect on short gravity waves using a microwave probe
No full textSAR detection and characterization of sea surface slicks
No full textIn this paper we demonstrate SAR system capability for detecting and characterizing marine surface slicks. During an aircraft measurement campaign over the Gulf of Genoa (Italy), a multi-frequency SAR system, operating in P-, L- and C-bands, explored a sea area heavily covered by slicks. At the same time in situ measurements were performed with an interferential microwave probe, installed on board a small boat, capable of measuring high resolution sea spectra up to frequencies of capillary waves. By plotting SAR pixel intensity versus sea wave Bragg frequency we obtained wide portions of the sea spectrum region affected by the surface film damping. Spectra derived from SAR imagery and from gauge data present comparable slopes and furthermore the ratio between clean to slicked water spectrum obtained with the two techniques were surprisingly similar. This demonstrates the multi-frequency SAR systems ability to detect and characterize sea surface films assuming the Bragg mechanism in the radar back-scatter. The outlined analysis suggests a simple methodology to monitor coastal water quality by using airborne SAR
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