Determination of Ocean Surface Descriptors Using Sea Photo Analysis Techniques
Abstract
The techniques of Sea Photo Analysis have been used to obtain surface truth descriptors of the open ocean from an aircraft. Aerial photographs were taken such that the density fluctuations of the negatives were related to surface slope. The slope spectra, obtained by Fourier analysis of the negatives, were fitted to an equivalent form of the Pierson-Moskowitz wave height spectrum. The photographs, the wave height spectrum, and the rms slope equations determined by Cox and Munk then yielded the averaged heading of the waves, the equivalent wind speed, the rms wave height, and the rms slope for clean and slick surfaces. The optical techniques of Sea Photo Analysis used in this program and digital analysis, used when whitecaps were present in the photographs, are discussed. The empirical equations used to determine rms wave height and slope and auxiliary rms slope and wave height spectrum equations are given. Surface descriptors were inferred for seas driven by winds from 3 to 21 knots occurring on 16 separate days.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 18, 1973
- Accession Number
- AD0764858
Entities
People
- Roger O. Pilon
Organizations
- United States Naval Research Laboratory