Environmental Descriptors for Ocean Bubbles and Acoustic Surface Backscatter.

摘要

LONG-TERM GOALS. This work will contribute to the development of a global, physics-based model with readily observable air-sea inputs (i.e., via satellite) for the prediction of acoustic surface scatter in littoral and open-ocean environments. SCIENTIFIC OBJECTIVES. The primary objectives of this study were to (1) describe the influence of bubble-related physical and biological factors on surface scattering strength (SSS), and (2) advance the development of surface wave descriptors for near-surface bubbles and acoustic backscatter. APPROACH. A diverse set of observations made during the Critical Sea Test (CST) field program was employed to empirically relate deviations from Ogden-Nicholas-Erskine (ONE) SSS model predictions to various physical and biological factors related to the supply, mixing, and removal of upper ocean bubbles. Furthermore, new surface wave descriptors were calculated from observed directional wave spectra using a wave spectral partitioning approach to isolate wind seas, and an extension of Phillips' (1985) Equilibrium Theory was used to estimate the total rate of wave dissipation by breaking. The dependence of wave dissipation rate on ocean surface whitecap coverage was described empirically.