The Interaction of Ocean Surface Processes, Waves, and Turbulence in the Adjacent Boundary Layers

Abstract

In order for air-sea exchange processes to be estimated in a dynamically consistent manner in the coupled atmosphere-ocean boundary-layer system, it is necessary to account for the dynamics of surface waves and other movements of the air-water interface. This is also necessary for the interpretation of turbulent flux observations made within the boundary layers, particularly those made from non-stationary measurement platforms. In recent years, considerable progress has been made in observational technology for the direct determination of the vertical flux of momentum, heat, and mass by eddy covariance techniques.We present an approach to the study of atmosphere-ocean boundary-layer fluxes which employs a general time-dependent coordinate formulation. To provide a uniform treatment both above and below the water surface it is advantageous to use the instantaneous sea surface as a coordinate surface. Reynolds covariances for turbulent flux are then replaced by more complex expressions, and we explore the implications for the design of flux measurement systems and modelling of the coupled interfacial/boundary-layer system. We show that for the flux of trace substances, and other scalar quantities such as heat, measurements of averaged fluxes from moving measurement platforms are subject to biases which are proportional to the square of the amplitude of the platform displacement or of the wave slope, and we indicate how such biases may be corrected or allowed for.

A wave-based model for the marginal ice zone including a floe breaking parameterization

“…By breaking up the floes, they can accelerate ice melting during summer due to enhanced lateral melting for small floes [ Steele et al , 1989; Steele , 1992], and promote ice formation during winter by creating interstices between ice floes where new ice can form. Waves can affect ice growth and heat fluxes in polynya and near the ice edge [ Lange et al , 1989], and significantly alter ocean mixing and air‐sea momentum transfer [ Janssen , 2004; Jenkins , 2007].…”

Modulation of Bjerknes feedback on the decadal variations in ENSO predictability

“…The BF intensity calculated using the 850 hPa wind is more closely related to the decadal variation of the ENSO predictability (i.e., the correlation coefficient is 0.63) than that calculated using surface wind stress or surface wind velocity (i.e., their respective correlation coefficients with the persistence forecast skill at leads 1–3 months are 0.47 and 0.49, and all pass the 10% significance level). The decrease in the correlation when adopting the surface wind/wind stress can be related to turbulent properties of the air‐sea interface [e.g., Jenkins , ].…”