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

PDF Url : ADA193867

Report Date : 04 Mar 1988

Pagination or Media Count : 15

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