摘要:

Internal waves were generated by a ship using the ‘dead water’ effect in areas where the water contains a strong near‐surface density gradient. The effects of these internal waves on wind waves were examined. The principal measurements were slope statistics of the wind waves and horizontal currents in the internal waves. The effects on the wind waves were always observable from an aircraft; however, in measurements made only along the ship's track the effects of the internal waves were not always readily distinguishable from other factors that influence the wind wave field. By using statistical techniques, relationships have been established between the wind waves, the internal waves, and the wind velocity. The principal finding is that the wind wave field is relatively more sensitive to internal wave currents at low wind speeds than at high wind speeds. Numerical values are

ISSN:0148-0227    

DOI:10.1029/JC083iC01p00443

年代:1978

数据来源: WILEY

摘要:

A theoretical description is given of the behavior of a broadband, small‐amplitude wind wave field in a perturbing internal wave velocity pattern. The theory includes the effect of the local wind. Specific predictions are made for the case of weak internal wave currents, and these predictions are compared with measurements. The theory predicts the magnitude of the mean square slope changes reasonably well, and it predicts the quadrant of the phases correctly. General features of the perturbed surface wave energy spectrum integrated in angle are also predicted reasonably well, and comparisons are made of the theoretical and measured local integrated spectrum at roughened areas and at slick area

ISSN:0148-0227    

DOI:10.1029/JC083iC01p00455

年代:1978

数据来源: WILEY

摘要:

Salinity data used to trace water movement or compute density are normally derived from measurements of chlorinity or electrical conductivity, temperature, and pressure. The latter technique has a precision about 1 order of magnitude greater than that of a typical chlorinity titration, but both are sensitive, in different ways, to variations in the ionic ratios of seawater. Present definitions of salinity are also ion dependent, causing significant variations in the salinity‐density relationship which cannot be simply expressed. In order to obtain density to an accuracy commensurate with the available precision it is best to define salinity in relation to a water mass of known ionic content so that a density correction to be applied to other water masses may be expressed as variations from a fixed standard. These corrections then appear in the form of simple additive constants for most waters, and where density difference is the important parameter, no correction is necessary within a specific water mass. The new salinity definition is based on dilution by weight of a conductivity ratio labeled standard seawater. It would be invariant under compositional variations and in accord with the proposed new equation of state (Grasshoff, 1976). It is conservative within acceptable limits, would provide a ‘practical salinity scale’ for use by oceanographers of all levels of sophistication, and would greatly facilitate data comparisons between institutions. The present variety of computational procedures for in situ data reduction would be replaced by one set of definitive equations that would not be subject to change as the precision of physical or chemical measurement improved. A great part of the data base necessary to write these equations exists, and the remainder should be available by

ISSN:0148-0227    

DOI:10.1029/JC083iC01p00466

年代:1978

数据来源: WILEY

摘要:

We describe the analysis of current and temperature cross spectra from the trimoored internal wave experiment Iwex and present a spectral model for the fluctuations in the internal wave range. The model consists of internal waves contaminated by temperature and current fine structure and by current noise. Except for the inertial and tidal frequencies the distribution of wave energy is vertically symmetric and horizontally isotropic. The wave number spectrum is characterized by a bandwidth of about 20–10 equivalent modes (decreasing with frequency), by a power law at high wave numbers, and by a sharp peak at low wave numbers. The general features of this spectrum agree fairly well with the one proposed by Garrett and Munk (1975). The contaminations increase with frequency. Contamination by temperature fine structure is confirmed by independent measurements. The Iwex spectral model provides a consistent description of all observed cross spectr

ISSN:0148-0227    

DOI:10.1029/JC083iC01p00479

年代:1978

数据来源: WILEY

摘要:

The light scattering intensities of white light, at various scattering angles, from glass spheres, crushed quartz, and mica flakes in suspension in water were measured. The light scattering distributions for the various shapes in the angular region from 0° to 90° were similar; however, in the region from 90° to 140° the distributions were quite different. The spheres produced the least scattering of light, and the plate‐shaped particles produced the greatest scattering of light in this region. A technique is proposed for the determination of shape utilizing light scattering by use of the ratio of light scattered at 90° to that scattered a

ISSN:0148-0227    

DOI:10.1029/JC083iC01p00501

年代:1978

数据来源: WILEY

摘要:

Air drops of surface drifter cards were made approximately monthly from December 1975 to September 1976 by helicopter south of Long Island. Drifters from three successive releases on April 13, May 25, and July 1 were recovered at Cape Cod, Martha's Vineyard, and Nantucket. The northeastward drift is attributed to anomalously persistent southerly winds.

ISSN:0148-0227    

DOI:10.1029/JC083iC01p00503

年代:1978

数据来源: WILEY