Air‐sea exchange of water vapor and sensible heat: The Humidity Exchange Over the Sea (HEXOS) results

Surface layer fluxes of sensible heat and water vapor were measured from a fixed platform in the North Sea during the Humidity Exchange over the Sea (HEXOS) Main Experiment (HEXMAX). Eddy wind stress and other relevant atmospheric and oceanic parameters were measured simultaneously and are used to interpret the heat and water vapor flux results. One of the main goals of the HEXOS program was to find accurate empirical heat and water vapor flux parameterization formulas for high wind conditions over the sea. It had been postulated that breaking waves and sea spray, which dominate the air-sea interface at high wind speeds, would significantly affect the air-sea heat and water vapor exchange for wind speeds above 15 m/s. Water vapor flux has been measured at wind speeds up to 18 m/s, sufficient to test these predictions, and sensible heat flux was measured at wind speeds up to 23 m/s. Within experimental error, the HEXMAX data do not show significant variation of the flux exchange coefficients with wind speed, indicating that modification of the models is needed. Roughness lengths for heat and water vapor derived from these direct flux measurements are slightly lower in value but closely parallel the decreasing trend with increasing wind speed predicted by the surface renewal model of Liu et al. [1979], created for lower wind speed regimes, which does not include effects of wave breaking. This suggests that either wave breaking does not significantly affect the surface layer fluxes for the wind speed range in the HEXMAX data, or that a compensating negative feedback process is at work in the lower atmosphere. The implication of the feedback hypothesis is that the moisture gained in the lower atmosphere from evaporation of sea spray over rough seas may be largely offset by decreased vapor flux from the air-sea interface.

[1]  M. H. Smith,et al.  Measurements of Humidity and Temperature in the Marine Environment during the HEXOS Main Experiment , 1994 .

[2]  Gerrit de Leeuw,et al.  Comment on “Sea spray and the turbulent air-sea heat fluxes” by Edgar L Andreas , 1994 .

[3]  E. L. Andreas.  Reply [to “Comment on ‘Sea spray and the turbulent air‐sea heat fluxes’ by Edgar L Andreas”] , 1994 .

[4]  K. Katsaros,et al.  Flow Distortion Calculations and Their Application in HEXMAX , 1994 .

[5]  A. Gruber,et al.  Validation of a Technique for Estimating Outgoing Longwave Radiation from HIRS Radiance Observations , 1994 .

[6]  M. Donelan,et al.  On the Dependence of Sea Surface Roughness on Wave Development , 1993 .

[7]  E. L. Andreas.  Sea spray and the turbulent air‐sea heat fluxes , 1992 .

[8]  L. Hasse,et al.  Sea surface wind stress and drag coefficients: The hexos results , 1992 .

[9]  W. Oost,et al.  An Improved Version of the Pressure Anemometer , 1991 .

[10]  Christopher W. Fairall,et al.  A study of the inertial‐dissipation method for computing air‐sea fluxes , 1991 .

[11]  Patrice G. Mestayer,et al.  A model of evaporating spray droplet dispersion , 1991 .

[12]  J. Decosmo.  Air-Sea Exchange of Momentum, Heat and Water Vapor Over Whitecap Sea States. , 1991 .

[13]  Christopher W. Fairall,et al.  Inertial-Dissipation Air-Sea Flux Measurements: A Prototype System Using Realtime Spectral Computations , 1990 .

[14]  Patrice G. Mestayer,et al.  Two Major Experiments in the Humidity Exchange over the Sea (HEXOS) Program , 1990 .

[15]  J. Willebrand,et al.  Fine Adjustment of Large Scale Air-Sea Energy Flux Parameterizations by Direct Estimates of Ocean Heat Transport , 1989 .

[16]  K. Katsaros,et al.  The K-Gill: A Twin Propeller-Vane Anemometer for Measurements of Atmospheric Turbulence , 1989 .

[17]  Stuart D. Smith.  Water vapor flux at the sea surface , 1989 .

[18]  Stuart D. Smith.  Coefficients for sea surface wind stress, heat flux, and wind profiles as a function of wind speed and temperature , 1988 .

[19]  J. Wyngaard.  The Effects of Probe-Induced Flow Distortion on Atmospheric Turbulence Measurements: Extension to Scalars , 1988 .

[20]  P. Mestayer,et al.  Spray droplet generation, transport, and evaporation in a wind wave tunnel during the humidity exchange over the sea experiments in the simulation tunnel , 1988 .

[21]  Edward C. Monahan,et al.  Air-Sea Exchange of Heat and Moisture During Storms , 1987 .

[22]  K. Katsaros,et al.  HEXOS—Humidity Exchange Over the Sea A Program for Research on Water-Vapor and Droplet Fluxes from Sea of Air at Moderate to High Wind Speeds , 1987 .

[23]  O. Tsukamoto.  Dynamic response of the fine wire psychrometer for direct measurement of water vapor flux , 1986 .

[24]  G. Geernaert,et al.  Variation of the drag coefficient and its dependence on sea state , 1986 .

[25]  W. Liu,et al.  Spatial variation of sea surface temperature and flux‐related parameters measured from aircraft in the JASIN Experiment , 1984 .

[26]  S. Kitaigorodskii.  On the Fluid Dynamical Theory of Turbulent Gas Transfer Across an Air-Sea Interface in the Presence of Breaking Wind-Waves , 1984 .

[27]  W. Oost.  The Pressure Anemometer—an Instrument for Adverse Circumstances , 1983 .

[28]  S. Kitaigorodskii,et al.  On the Theory of the Equilibrium Range in the Spectrum of Wind-Generated Gravity Waves , 1983 .

[29]  C. Fairall,et al.  Observed inter-relations between 10m winds, ocean whitecaps and marine aerosols , 1983 .

[30]  W. Large,et al.  Sensible and Latent Heat Flux Measurements over the Ocean , 1982 .

[31]  W. Timothy Liu,et al.  An Operational Large-Scale Marine Planetary Boundary Layer Model , 1982 .

[32]  J. Wyngaard,et al.  The Effects of Probe-Induced Flow Distortion on Atmospheric Turbulence Measurements , 1981 .

[33]  Stuart D. Smith,et al.  Evaporation coefficient for the sea surface from eddy flux measurements , 1981 .

[34]  S. Ling,et al.  Microdroplets and Transport of Moisture from Ocean , 1980 .

[35]  Edward C. Monahan,et al.  Optimal Power-Law Description of Oceanic Whitecap Coverage Dependence on Wind Speed , 1980 .

[36]  Stuart D. Smith.  Wind Stress and Heat Flux over the Ocean in Gale Force Winds , 1980 .

[37]  C. Fairall,et al.  Humidity Effects and Sea Salt Contamination of Atmospheric Temperature Sensors , 1979 .

[38]  W. Liu,et al.  Bulk Parameterization of Air-Sea Exchanges of Heat and Water Vapor Including the Molecular Constraints at the Interface , 1979 .

[39]  P. Hobbs,et al.  Comments on the Climax and Wolf Creek Pass Cloud Seeding Experiments , 1979 .

[40]  Gordon E. Schacher,et al.  Observation of the temperature structure function parameter, CT2, over the ocean , 1978 .

[41]  S. Nicholls.  Measurements of turbulence by an instrumented aircraft in a convective atmospheric boundary layer over the sea , 1978 .

[42]  L. Merlivat.  The dependence of bulk evaporation coefficients on air‐water interfacial conditions as determined by the isotopic method , 1978 .

[43]  R. Street,et al.  Transfers across an air‐water interface at high wind speeds: The effect of spray , 1978 .

[44]  E. Deacon,et al.  Gas transfer to and across an air-water interface , 1977 .

[45]  Kristina B. Katsaros,et al.  The sea surface temperature deviation at very low wind speeds; is there a limit? , 1977 .

[46]  C. Friehe,et al.  Parameterization of Air-Sea Interface Fluxes of Sensible Heat and Moisture by the Bulk Aerodynamic Formulas , 1976 .

[47]  S. Ling,et al.  Parameterization of the Moisture and Heat Transfer Process over the Ocean under Whitecap Sea States , 1976 .

[48]  Wilfried Brutsaert,et al.  A theory for local evaporation (or heat transfer) from rough and smooth surfaces at ground level , 1975 .

[49]  A. Dyer.  A review of flux-profile relationships , 1974 .

[50]  M. Lemone,et al.  An Experimental Study of Turbulence Structure in the Fair-Weather Trade Wind Boundary Layer , 1974 .

[51]  Stuart D. Smith.  Eddy flux measurements over Lake Ontario , 1974 .

[52]  E. F. Bradley,et al.  Flux-Profile Relationships in the Atmospheric Surface Layer , 1971 .

[53]  P. M. Saunders,et al.  The Temperature at the Ocean-Air Interface , 1967 .

[54]  E. Appleton.  An introduction to atmospheric physics , 1964 .

[55]  P. R. Owen,et al.  Heat transfer across rough surfaces , 1963, Journal of Fluid Mechanics.

[56]  G. Ewing,et al.  On the Thermal Boundary Layer of the Ocean , 1960, Science.

[57]  Edgar L. Andreas,et al.  The spray contribution to net evaporation from the sea: A review of recent progress , 1995 .

[58]  G. Geernaert,et al.  Bulk Parameterizations for the Wind Stress and Heat Fluxes , 1990 .

[59]  M. Rouault.  Modélisation numérique d'une couche limite unidimensionnelle stationnaire d'embruns , 1989 .

[60]  S. F. Zhang.  a Critical Evaluation of the Von Karman Constant from a New Atmospheric Surface Layer Experiment. , 1988 .

[61]  D. E. Spiel,et al.  A Model of Marine Aerosol Generation Via Whitecaps and Wave Disruption , 1986 .

[62]  D. M. Doyle,et al.  Whitecaps and Global Fluxes , 1986 .

[63]  S. Kitaigorodskii,et al.  Wind-Wave Effects on Gas Transfer , 1984 .

[64]  J. A. Businger,et al.  Equations and Concepts , 1984 .

[65]  K. L. Davidson,et al.  An analysis of the surface production of sea-salt aerosols By C. W. FAIRALL, BDM Corporation, Naval Postgraduate School, Monterey, California 93940, U.S.A. , 1983 .

[66]  J. Launiainen.  Parameterization of the water vapour flux over a water surface by the bulk aerodynamic method , 1983 .

[67]  W. Shaw,et al.  The Effect of and Correction for Different Wet-Bulb and Dry-Bulb Response in Thermocouple Psychrometry , 1980 .

[68]  C. Friehe,et al.  Humidity Sensitivity of Atmospheric Temperature Sensors by Salt Contamination , 1978 .

[69]  S. Ling,et al.  Mechanics of Multiphase Fluxes Over the Ocean , 1978 .

[70]  G. Kruspe.  On moisture-flux parameterization , 1977 .

[71]  J. Garratt,et al.  Vertical Fluxes of Momentum Sensible Heat and Water Vapour During the Air Mass Transformation Experiment (AMTEX) 1974 , 1975 .