摘要:

Historical notes.In 1893 the Norwegian explorer Fridtjof Nansen started on an Arctic Ocean expedition in his brand new wooden ship theFram, which was to be allowed to freeze into the arctic ice pack and then hopefully to drift with her crew still aboard across the entire arctic basin. It was to be a test of Nansen's theory of a polar current and would allow numerous scientific observations to be made. It took theFram3 years finally to drift across the top of the world. She reached a latitude of 85° 57″N, a record not surpassed until the nuclear submarineNautilusreached the north pole in 1958 by going under the arctic ice pa

ISSN:0148-0227    

DOI:10.1029/JC080i003p00289

年代:1975

数据来源: WILEY

摘要:

We present a revised model for the distribution of internal wave energy in wave number frequency space. The model is empirical, guided by the following measurements: moored spectra and moored coherences for horizontal and vertical separations (MS, MHC, MVC as functions of frequency), towed spectra and towed vertical and time‐lagged coherences (TS, TVC, TLC as functions of horizontal wave number), and dropped spectra and dropped horizontal and lagged coherences (DS, DHC, DLC as functions of vertical wave number). Measurements are available for all but TLC and DHC. There is some indication of universality, suggesting perhaps a saturation limi

ISSN:0148-0227    

DOI:10.1029/JC080i003p00291

年代:1975

数据来源: WILEY

摘要:

An instrument package has been developed that drifts along freely with the water while it repeatedly profiles ocean temperature. Profiling during drifting reduces the Doppler and fine structure effects that usually contaminate internal wave measurements. Six days of exceptionally clean internal wave records were acquired 470 km offshore of San Diego, California, in June 1973 at a nominal depth of 800 m. The resulting vertical displacement spectra decrease generally as ω−2up to the local Brunt‐Väisälä (B‐V) frequency. Just below the B‐V frequency there is a spectral peak. Above the B‐V frequency the spectra drop sharply to low levels. Vertical coherence of internal waves over a separation of 100 m was found to be 0.8 and fairly independent of frequency up to the B‐V frequency. An internal wave model proposed by Garrett and Munk is in general agreement with the observed features. Both the measured coherence and the oscillatory nature of the spectrum near the B‐V cutoff are consistent with an energy concentration in the lower six or so modes. In addition to the internal wave records, continual changes in the thermal structure were observed by the drifting package. One repeating thermal inversion pattern occurred four times during the 6‐day therm

ISSN:0148-0227    

DOI:10.1029/JC080i003p00299

年代:1975

数据来源: WILEY

摘要:

The coherence between vertical temperature profiles separated in time is studied. Time lags from 12 min to 19 hours and vertical wavelengths from 2 to 300 m are considered. The wavelengths shorter than 10 m show no significant coherence even for 12‐min separations. The longer wavelength bands exhibit coherence time series with significant structure out to the largest lag measured. For the wavelength band between about 21 and 42 m the results are directly interpretable as vertical modes. In the other wavelength bands considered, there is evidence that the perturbations are propagating. The coherence and phase time series are compared with the Garrett and Munk internal wave mode

ISSN:0148-0227    

DOI:10.1029/JC080i003p00307

年代:1975

数据来源: WILEY

摘要:

A 3‐hour record of the vertical displacement of a density step, initially located at 190‐m depth and sampled at 30‐s intervals from a stable platform (ice island T3), yields a high‐resolution picture of the internal waves at the densi

ISSN:0148-0227    

DOI:10.1029/JC080i003p00312

年代:1975

数据来源: WILEY

摘要:

The vertical fine structure statistics in the northwest Atlantic (midocean dynamics experiment area) have been studied by using the Woods Hole Oceanographic Institution/Brown CTD (conductivity, temperature, and depth). Five depth intervals including water masses representative of the entire water column have been subjected to spectral analysis of the temperature line structure. All intervals show a similar power law dependence upon vertical wave number of −2.5, although spectral levels vary by more than a factor of 1000, whereas differences of only a factor of 2 exist on estimated vertical displacement spectra. Results are not inconsistent with the supposition that internal waves are responsible for much of the variability. On scales smaller than 10 m in the main thermocline features with the characteristic signature of sheets and layers begin to appea

ISSN:0148-0227    

DOI:10.1029/JC080i003p00314

年代:1975

数据来源: WILEY

摘要:

The generation of internal waves by the interaction of deep ocean flows with bottom topography is considered. The interaction of quasi‐steady currents with the bottom topography is found to produce an internal wave drag and associated momentum flux of roughly ½ dyn/cm2, which is comparable to the average wind stress on the ocean surface. The waves are probably dissipated by critical layer phenomena in the lowest kilometer or so of the ocean, the result being a wave‐induced vertical mixing coefficient of order 10 cm2/s in that portion of the water column. The interaction of the barotropic tide with the bottom topography is found to result in a flux of energy of order 1 erg/cm2s into the internal tide, which may represent a nonnegligible sink of the tidal energy. This mechanism appears to be capable of supplying a significant portion of the observed internal wave energy in the ocean. The internal tide is probably dissipated by inherently nonlinear phenomena: spectral transport by weak interactions and, in the upper oceans, strong interactions manifested by localized instabilities resulting in isolated patches of turbul

ISSN:0148-0227    

DOI:10.1029/JC080i003p00320

年代:1975

数据来源: WILEY

摘要:

This paper is a broad review of the theoretical studies of the physical processes affecting the excitation, dissipation, and interaction of internal waves in the deep ocean.

ISSN:0148-0227    

DOI:10.1029/JC080i003p00328

年代:1975

数据来源: WILEY

摘要:

We review the state of observation of internal waves in the light of suggestions that there is a universal isotropic spectrum. The general conclusion is that the data are inadequate to draw such an inference at this time. A universal spectrum is also precluded, since it forbids sources and sinks for the motion. The deviations from homogeneous models are the physically significant quantities, and certain zero‐order questions are proposed to study these deviation

ISSN:0148-0227    

DOI:10.1029/JC080i003p00339

年代:1975

数据来源: WILEY

摘要:

Measurements of the directly transmitted ultraviolet solar flux in 2‐Å intervals in the range 2981–4000 Å had been obtained at Boulder, Colorado, over a period of 2 years. A spectrum of the extraterrestrial solar flux has been derived from these data by use of a modified Langley method. This spectrum is compared with several spectra measured by other investigators, and differences are discussed. The measurements are also used to obtain total ozone and dust extinction as a function of wavelength. The ozone results are compared with total ozone measured concurrently by the Dobson spectro

ISSN:0148-0227    

DOI:10.1029/JC080i003p00345

年代:1975

数据来源: WILEY