The effect of monomolecular surface films on the microwave brightness temperature of the sea surface

Alpers, Werner; Blume, Hans-Juergen C.; Garrett, William D.; Hühnerfuß, Heinrich

doi:10.1080/01431168208948415

Cited by 23 publications

(7 citation statements)

References 18 publications

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“…It will also be important to extend this approach to relate composition to dynamically measured physical properties which may differ from quasistatic properties. The decades long interest in the surface physical properties of the air-sea interface in the presence of organic films has been due to the need to understand their influence on wave damping [Cini and Lombardini, 1978;Hiihnerfuss et al, 1981Hiihnerfuss et al, , 1983aHiihnerfuss et al, , 1987Alpers and Hiihnerfuss, 1989]; recently, intensified research has been stimulated by recognition of the potential influence of organic films on the remote imaging of the ocean surface by various active and passive sensors (visible, infrared, and microwave) [Soules, 1970;Brown et al, 1976;Alpers et al, 1982;Vesecky and Stewart, 1982;Hiihnerfuss et al, 1983b;Kaltenbach et al, 1984;Garrett, 1986]. Measurements of wind speed using scatterometers are subject to errors in wind speedbackscatter relationships believed due in part to surface films [Stewart, 1985] In the interpretation of these images and modeling of the underlying processes, the interfacial elasticity is a key parameter [Lucassen-Reynders and Lucassen, 1969; Bock and Mann, 1989]; thus it becomes important to be able to predict the likely range of variability of surface elasticity from one region to another and to estimate changes in surface elasticity as a function of the intensity of surface convergence.…”

Section: Concluding Commentsmentioning

confidence: 99%

Scaling of marine microlayer film surface pressure‐area isotherms using chemical attributes

Frew¹,

Nelson²

1992

J. Geophys. Res.

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Heterogeneity in the chemical composition of sea surface films due to variation in sources of surfactant materials and in physical dynamics during film formation may lead to spatial and temporal variability in interfacial physical properties. Alternatively, slick physical properties may be postulated to be largely averaged and therefore similar across a variety of oceanic regimes. In order to assess interslick variability in regimes of different productivity, surface pressure‐area (π‐A) isotherms have been measured for a suite of microlayers sampled at stations in productive coastal and mesotrophic waters of the southern California Bight. Surface‐active organics isolated from the microlayers by solid phase extraction on C18 Sep‐Pak cartridges were respread on clean seawater, and the π‐A isotherms of the reconstituted films were determined. Several bulk chemical parameters including dry weight, UV absorbance, and carbon, nitrogen, and lipid content have been examined in an attempt to scale the isotherms; the latter were shown not to collapse to a single well‐constrained envelope when compared on a specific area basis. However, for several parameters there was a clear separation of the slicked microlayer isotherms into two distinct film types composed primarily of inshore and offshore samples, respectively. Area scaling and virial equation modeling also clustered the isotherms into two groups with different elastic properties suggesting the presence of distinct “end‐member” components. Surfactants from an unslicked microlayer appeared to produce films that exhibited much lower elastic moduli than those from slicked microlayers. The observed interslick variability in π‐A characteristics was larger than the uncertainties inherent in the methodology, and it was concluded that the variability was related to significant differences in chemical composition of films. The inferred compositional differences must be taken into account in order to correctly define interfacial boundary conditions in modeling of wind‐wave interactions.

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Section: Concluding Commentsmentioning

confidence: 99%

Scaling of marine microlayer film surface pressure‐area isotherms using chemical attributes

Frew¹,

Nelson²

1992

J. Geophys. Res.

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“…The physical and chemical properties of sea surface microlayer films have been studied extensively (for reviews, see Hunter and Liss [1981], Hartwig and Herr [1984], and Herr and Williams [ 1986] [Goldman et al, 1988;Frew et al, 1990], marine aerosol formation [Blanchard, 1964;Gershey, 1983], and recently, their effects on sea surface imaging by various types of remote sensing platforms [Alpers et al, 1982;Hiihnerfuss et al, 1983;Garrett, 1986;Scott, 1986]. Considerable effort has been focused on measurement of surface pressure-area isotherms and elastic properties of sea surface films [Jarvis et al, 1967;Barger eta!., 1974;Barger and Means, 1985;Barger, 1985].…”

Section: Introductionmentioning

confidence: 99%

Isolation of marine microlayer film surfactants for ex situ study of their surface physical and chemical properties

Frew¹,

Nelson²

1992

J. Geophys. Res.

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Surface‐active organic matter from natural marine microlayers has been isolated by solid phase adsorption using reversed phase (C18) cartridges. Surfactants collected from a suite of microlayer films in the California Bight and the Gulf of Maine and isolated by this technique were respread on clean seawater to reconstitute surface films which exhibited surface pressure‐area (π‐A) isotherms and static (Gibbs) surface elasticities closely approximating those measured for films formed by diffusion in the original fresh microlayer samples. Microlayer‐subsurface (10 cm depth) carbon enrichment factors were estimated to range from 3.9 to 16. The estimated mean recovery of microlayer dissolved organic carbon (DOC) was 20 ± 5%. The select hydrophobic DOC fraction isolated was the dominant surfactant class responsible for microlayer film characteristics as measured quasi‐statically, even though other relatively hydrophilic DOC fractions which may have been enriched in the microlayer were not absorbed and passed through the isolation procedure. This technique allows collection of marine microlayer films for systematic ex situ study and correlation of their surface physical and chemical properties. For the first time, the π‐A isotherms for microlayer films can be expressed on a specific area basis and, in cases where molecular weights can be estimated, according to mean molecular area.

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“…and Garrett 1974;Hiihnerfuss and Garrett 1981). In recent years several phenomena have been investigated with the help of artificial surface films: evaporation (La Mer 1972;Mansfield 1972), windwave-and wave-wave-coupling (Barger et al 1970;Mallinger and Mickelson 1973;Hiihnerfuss et al 1975Hiihnerfuss et al , 1981u, 1982, the modification of brightness temperature of the sea surface by slicks (Alpers et al 1982), and the influence of slicks on KU-band (IIiihnerfuss et al 1978) and X-and L-band radar signals (IIiihnerftlss et al 1981u).…”

mentioning

confidence: 99%

Artificial surface films in the sea area near Sylt1

Brockmann

Hühnerfuß

Kattner

et al. 1982

Limnology & Oceanography

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An artificial surface fihn of oleyl alcohol was produced in the North Sea off Sylt Island to investigate the chemical uniformity of the surface filrn and its influence on gas exchange. Oleyl alcohol concentrations found at the sea surface were in good agreement with previously calculated values. Significant differences between fatty acid concentrations before and after production of the artificial film indicated that the natural surface-active substances were pushed aside by the spreading oleyl alcohol, with small amounts replenished from the underlying water later. The same displacement effect was inferred from the strong reduction in the number of colony-forming units of organotrophic bacteria in the presence of an oleyl alcohol slick. Gas exchange, in this cast dcsorption of CO,, was determined before and after formation of the artificial surface film. In the one experiment performed inhibition of exchange was significant when the film was present: without the film cquilibril~m was achieved after 3.7 Inin, whereas lmder the influence of the film, it took 5.7 min to reach equilibrium.

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The effect of monomolecular surface films on the microwave brightness temperature of the sea surface

Cited by 23 publications

References 18 publications

Scaling of marine microlayer film surface pressure‐area isotherms using chemical attributes

Scaling of marine microlayer film surface pressure‐area isotherms using chemical attributes

Isolation of marine microlayer film surfactants for ex situ study of their surface physical and chemical properties

Artificial surface films in the sea area near Sylt1

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