| Автор | Merlivat, Liliane |
| Дата выпуска | 1978 |
| dc.description | The analysis of the natural distribution of deuterium and oxygen 18 in moisture inside the turbulent boundary layer developed above a water surface makes possible the investigation of the mechanism of evaporation. The distribution of isotopes in water vapor allows the calculation of the relative contributions of molecular and turbulent transfer to the total mass transport (Merlivat and Coantic, 1975). We have applied this method to assess the influence of the conditions at the liquid surface on the evaporation flux. In particular, the influence of wind waves and superposed artificially generated waves was studied. Experiments have been carried out at the Institut de Mécanique Statistique de la Turbulence air‐water tunnel, specially designed for the simulation of ocean‐atmosphere energy exchanges. Here the wind velocities could be varied from 0.7 to 6 m/s. Waves were generated by a motor‐driven paddle. The wave frequency was 1 Hz, and the maximum height 12 cm, while the surface roughness Reynolds number Re<sub>s</sub> varied from 0.02 to 2. Mean wind velocity profiles and isotopic profiles were measured. Experimental drag coefficients are described quite well by Charnock's relation Z<sub>0</sub> = u<sub>*</sub><sup>2</sup>/ag., where a = 81.1. No specific difference is observed when waves are artificially generated. Agreement between experiment and theoretical isotopic distribution is checked for six models proposed to describe evaporation processes. Quite good agreement is found with Brutsaert's model (Brutsaert, 1975a,b) for a smooth surface if Re<sub>s</sub> < 1 and for a rough surface if Re<sub>s</sub> > 1. Again, no specific effect due to the presence of artificially generated waves is observed. The above observations allow, then, the calculation of the drag and bulk evaporation coefficients, C<sub>D</sub> and C<sub>q</sub>, as a function of the surface roughness Reynolds number: these coefficients, as well as their ratio, when calculated for a height of z = 10 m, vary from 0.99 × 10<sup>−3</sup> to 1.24 × 10<sup>−3</sup> and from 1.31 to 0.84, respectively, when Re<sub>s</sub> increases from 0.02 to 10, corresponding to a mean wind speed range extending from 2 to 13 m/s. These evaporation bulk transfer coefficients are given for near‐neutral stability conditions of the atmospheric layer. In the case of moderate instability, frequently observed over the sea, we would expect, and we observe, that the transfer coefficients are generally higher. |
| Формат | application.pdf |
| Копирайт | Copyright 1978 by the American Geophysical Union. |
| Тема | "Symposium on Oceanic Microstructures |
| Тема | HYDROLOGY |
| Тема | Hydrology: Evaporation |
| Тема | ATMOSPHERIC PROCESSES |
| Тема | Meteorology: H₂O in the atmosphere (humidity, clouds, and precipitation) |
| Тема | OCEANOGRAPHY: GENERAL |
| Тема | Oceanography: Boundary layer and exchange processes |
| Название | The dependence of bulk evaporation coefficients on air‐water interfacial conditions as determined by the isotopic method |
| Тип | article |
| DOI | 10.1029/JC083iC06p02977 |
| Electronic ISSN | 2156-2202 |
| Print ISSN | 0148-0227 |
| Журнал | Journal of Geophysical Research: Oceans |
| Том | 83 |
| Первая страница | 2977 |
| Последняя страница | 2980 |
| Выпуск | C6 |
| Библиографическая ссылка | Brutsaert, W., A theory for local evaporation (or heat transfer) from rough and smooth surfaces at ground level, Water Resour. Res., 11, 543–550, 1975a. |
| Библиографическая ссылка | Brutsaert, W., The roughness length for water vapor, sensible heat, and other scalars, J. Atmos. Sci, 32, 2028–2031, 1975b. |
| Библиографическая ссылка | Coantic, M., A.Favre, Activities in, and preliminary results of, air‐sea interactions research at I.M.S.TProceedings of the Second IUTAM‐IUGG Symposium on Turbulent Diffusion in Environmental PollutionInt. Union of Theor. and Appl. Mech. and Int. Union of Geod. and Geophys.Charlottesville, Va.April 8–14, 1974. |
| Библиографическая ссылка | Deacon, E. L., E. K.Webb, The Sea, 1M. N.Hill, 81, Interscience, New York, 1962. |
| Библиографическая ссылка | Deardorff, J. W., Dependence of air‐sea transfer coefficients on bulk stability, J. Geophys. Res., 73, 2549–2557, 1968. |
| Библиографическая ссылка | Easterbrook, C. C., A study of the effects of waves on evaporation from free water surfacesRes. Rep. 18U.S. Dep. of the Interior, Washington, D. C., 1968. |
| Библиографическая ссылка | Friehe, C. A., K. F.Schmitt, Parameterization of air‐sea interface fluxes of sensible heat and moisture by the bulk aerodynamic formulas, J. Phys. Oceanogr., 6, 801–809, 1976. |
| Библиографическая ссылка | Hicks, B. B., Some valuations of drag and bulk transfer coefficients over water bodies of different sizes, Boundary Layer Meteorol., 3, 201–214, 1972. |
| Библиографическая ссылка | Kitaigorodskiy, S. A., O. A.Kuznetsov, G. N.Panin, Coefficients of drag, sensible heat, and evaporation in the atmosphere over the surface of a sea, Izv. Akad. Sci. USSR, Atmos. Oceanic Phys., 911, 1135–1141, 1973. |
| Библиографическая ссылка | Merlivat, L., Determination of the molecular diffusion coefficients of H<sub>2</sub><sup>16</sup>O, HDO and H<sub>2</sub><sup>18</sup>O in air, J. Chem. Phys., 1978. |
| Библиографическая ссылка | Merlivat, L., M.Coantic, Study of mass transfer at the air‐water interface by an isotopic method, J. Geophys. Res., 80, 3455–3464, 1975. |
| Библиографическая ссылка | Owen, P. R., W. R.Thomson, Heat transfer across rough surfaces, J. Fluid Mech., 15, 321–334, 1963. |
| Библиографическая ссылка | Smith, S. D., E. G.Banke, Variation of the sea surface drag coefficient with wind speed, Quart. J. Roy. Meteorol. Soc., 101, 665–673, 1975. |
