Eddy flux measurements over the ocean and related transfer coefficients

Abstract

Eddy correlation measurements of vertical turbulent fluxes made during AMTEX 1975 are used to assess the reliability of flux prediction from established bulk transfer relations, using both surface-layer and planetary boundary-layer formulations. The surface-layer formulae predict momentum and latent heat fluxes to an accuracy comparable to the direct eddy correlation method, using transfer coefficients of CDN (at 10m and in neutral conditions) increasing with wind speed, and a constant CEN ∼- 1.5 × 10−3. The data suggest CCHN, for sensible heat, increases significantly with wind speed and is on average 30% lower than CCEN The boundary-layer drag coefficient, CGD, agrees within about 40% of recently published values using a vertically averaged geostrophic wind to the height of the lowest temperature inversion, corrected for trajectory curvature. Values of θ*/δθ from which CCGH is derived, are in excellent agreement if the published values are modified to account for inappropriate surface temperatures used in their derivation. Preliminary values of CGE are also presented.