Bulk Parameterization of Air-Sea Exchanges of Heat and Water Vapor Including the Molecular Constraints at the Interface

• Published in: Journal of the atmospheric sciences 1979-09, Vol.36 (9), p.1722-1735
• Main Authors: Liu, W. Timothy, Katsaros, Kristina B., Businger, Joost A.
• Format: Article
• Language: English
• ISSN: 0022-4928; 1520-0469
• DOI: 10.1175/1520-0469(1979)036<1722:bpoase>2.0.co;2

A model is developed for the marine atmospheric surface layer, including the interfacial sublayers on both sides of the air-sea interface where molecular constraints on transports are important. Flux-profile relations that are based upon the postulation of intermittent renewal of the surface fluid are matched to the logarithmic profiles and compared with field and laboratory measurements. These relations permit numerical determination of air-sea exchanges of momentum, heat, and water vapor (or bulk transfer coefficients) by using the bulk parameters of mean wind speed, temperature, and humidity at a certain height in the atmospheric surface layer, and the water temperature. With increasing wind speed, the flow goes from smooth to rough and the bulk transfer coefficient for momentum also increases. The increase in roughness is associated with increasing wave height, which in this model results in sheltering at the wave troughs. Because of the decrease in turbulent transports, the transfer coefficients of heat and water vapor decrease slightly with wind speed, after the wind speed exceeds a certain value. The bulk transfer coefficients are also found to decrease with increasing stability. If the bucket temperature, which typically gives the water temperature a few centimeters below the surface is used, rather than the interfacial temperature, erroneous results may be obtained when the air-sea temperature difference is small. By including the effects of stability and interfacial conditions in bulk parameterization, the model provides a way to explain the physical conditions that are known to affect air-sea exchanges.