Method and system for depth sounding

1989 ◽  
Vol 85 (4) ◽  
pp. 1805-1805
Author(s):  
Philippe de Heering
Keyword(s):  
Depth Sounding

scholarly journals 4SM: A Novel Self-calibrated Algebraic Ratio Method for Satellite Derived Bathymetry and Water Column Correction

2017 ◽  
Author(s):  
Yann George MOREL
Keyword(s):  
Water Column ◽  
Radiative Transfer Equation ◽  
Atmospheric Correction ◽  
Ratio Method ◽  
Published Data ◽  
Deep Waters ◽  
Bare Land ◽  
Depth Sounding ◽  
Radiance Data ◽  
The Ideal

All empirical water column correction methods have consistently been reported to require existing depth sounding data for the purpose of calibrating a simple depth retrieval model; they yield poor results over very bright or very dark bottoms. In contrast, we set out to (i) use only the relative radiance data in the image along with published data, and several new assumptions, (ii) in order to specify and operate the simplified radiative transfer equation (RTE), (iii) for the purpose of retrieving both the satellite derived bathymetry (SDB) and the water column corrected spectral reflectance over shallow seabeds. Sea truth regressions show that SDB depths retrieved by the method only need tide correction. Therefore it shall be demonstrated that, under such new assumptions, there is no need (i) for formal atmospheric correction, (ii) nor for conversion of relative radiance into calibrated reflectance , (iii) nor for existing depth sounding data, to specify the simplified RTE and produce both SDB and spectral water column corrected radiance ready for bottom typing. Moreover, the use of the panchromatic band for that purpose is introduced. Altogether, we named this process the Self-Calibrated Supervised Spectral Shallow-sea Modeler (4SM). This approach requires a trained practitioner, though, to produce its results within hours of downloading the raw image. The ideal raw image should be a “near-nadir” view, exhibit homogeneous atmosphere and water column, include some coverage of optically deep waters and bare land, and lend itself to quality removal of haze, atmospheric adjacency effect, and sun/sky glint.

scholarly journals Helicopter-borne radio-echo sounding of Svartisen, Norway

1993 ◽  
Vol 17 ◽  
pp. 23-26 ◽  
Author(s):  
Michael Kennett ◽  
Tron Laumann ◽  
Cecilie Lund
Keyword(s):  
Low Frequency ◽  
Ice Thickness ◽  
Digital Receiver ◽  
Outlet Glacier ◽  
Northern Norway ◽  
Bed Topography ◽  
Ice Cap ◽  
Radio Echo Sounding ◽  
Depth Sounding ◽  
Ice Radar

A helicopter-mounted low frequency ice-radar has been developed for the depth sounding of temperate glaciers. The radar consists of standard transmitter and digital receiver equipment. The long antennae are supported on a special aluminium and fibreglass construction which hangs 20 m below the helicopter. The radar has been used on Engabreen, an outlet glacier of the Svartisen Ice Cap in northern Norway, where ice thicknesses of up to 350 m were obtained. The results have been used to construct a map of bed topography of the lower part of Engabreen. This map is largely consistent with ice thickness data obtained by drilling.

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