Accession Number:

ADA193867

Title:

A Probabilistic Model of the Apparent Radiance of a Rough Sea.

Descriptive Note:

Memorandum rept.,

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s):

• Priest, R. G.
• Schwartz, I. B.

Report Date:

1988-03-04

Pagination or Media Count:

15.0

Abstract:

A widely used approach to the specification of the background statistics of wind driven sea states is the power spectral method. Coupled with a ray trace of the sky radiance, one can create deterministic images of a rough sea in the infrared. In this paper a probabilistic model of a rough sea is presented as an alternative to the power spectral approach. The model takes into account self-shadowing of the sea surface which is important when the sea is viewed at near grazing angles. Given such a model, the apparent radiance of a rough sea is shown to emit a substantially lower amount of radiation when compared to a smooth sea. The sea, being a poor emitter of radiation at near grazing angles, reflects cool sky radiation from higher points in the sky and therefore looks colder than its blackbody temperature.

Descriptors:

• *OCEAN SURFACE
• *RADIANCE
• ANGLES
• BACKGROUND
• BLACKBODY RADIATION
• COOLING
• DETERMINANTS(MATHEMATICS)
• GRAZING
• INFRARED IMAGES
• MATHEMATICAL MODELS
• POWER SPECTRA
• PROBABILITY
• INFRARED RADIATION
• RAY TRACING
• SEA STATES
• SKY
• STATISTICAL DISTRIBUTIONS
• TEMPERATURE
• WIND
• SURFACE ROUGHNESS
• EMISSIVITY
• INFRARED SIGNATURES
• SHADOWS

Subject Categories:

• Physical and Dynamic Oceanography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE