Accession Number:

ADA278008

Title:

Ocean Surface Roughness from Infrared Measurements: A Failure of Shape from Reflection

Descriptive Note:

Final rept.

Corporate Author:

NAVAL COMMAND CONTROL AND OCEAN SURVEILLANCE CENTER RDT AND E DIV SAN DIEGO CA

Personal Author(s):

• Anderson, K. D.

Report Date:

1993-05-01

Pagination or Media Count:

36.0

Abstract:

The objective of this effort is to test the practicality of an instrument that uses the reflection coefficient modulated radiance shape from reflection to measure the roughness of the sea surface. Conceptually, this instrument would be used aboard ship to remotely sense the ocean wave spectrum of the sea surface ideally, the ocean wave spectrum covered by this instrument would range from very long wavelengths, on the order of decameters, to very short wavelengths, on the order of centimeters. A series of wave tank measurements made at the Scripps Institution of Oceanography SIO, San Diego, CA, clearly show that the technique is impractical. The technical difficulties are associated with the failure of several necessary assumptions of shape from reflection. The first assumption is that the sky illumination source is nearly isotropic in practice, this assumption is not valid. The second assumption is that the nonlinear relationship between the reflection coefficient and wave slop is not a fundamental limiting factor in practice, the sensitivity of the reflection coefficient to incidence angle appears to be a limiting factor. The technique of measuring the ocean wave spectrum by shape from reflection is not viable and should not be pursued.

Descriptors:

• *INFRARED DETECTION
• *OCEAN SURFACE
• *REFLECTION
• *SURFACE ROUGHNESS
• OCEAN WAVES
• TARGET DETECTION
• SEA STATES
• ANGLE OF INCIDENCE
• RADIANCE
• SHAPE
• ELECTROMAGNETIC WAVE PROPAGATION
• ILLUMINATION

Subject Categories:

• Physical and Dynamic Oceanography
• Infrared Detection and Detectors
• Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE