Normalizing Air-Sea Flux Coefficients for Horizontal Homogeneity, Stationarity, and Neutral Stratification

Abstract Monin–Obukhov similarity (MOS) theory is routinely applied over the ocean to describe surface layer profiles of wind speed, temperature, and gas concentrations. Using this theory, fluxes are in turn estimated based on the best available parameterizations of normalized flux coefficients: for example, neutral flux coefficients. Flux coefficients can vary with environmental conditions. Because it is generally assumed that the domain of interest must be characterized by spatially homogeneous and steady-state conditions, systematic violations of the assumptions may lead to significant uncertainties in flux estimates. In this paper, the author has extended MOS theory to accommodate nonstationarity and spatial inhomogeneity in the representation of the normalized drag coefficient, Stanton number, and Dalton number. The author illustrates the importance of his theoretical extension, based on a reexamination of a historical air–sea interaction dataset obtained from the North Sea.