摘要:

Nitric oxide mixing ratios have been measured under high sun conditions in the stratosphere over the altitude range 17–30.5 km during four balloon flights launched from New Mexico. Experimental evidence is also presented to confirm that no serious sampling errors were encountered either from contamination of the sampled air or from removal of nitric oxide in the inlet to the instrumen

ISSN:0148-0227    

DOI:10.1029/JC080i015p01925

年代:1975

数据来源: WILEY

摘要:

Spectra from the satellite instrument Iris (infrared interferometer spectrometer) were examined to find the number of independent variables needed to describe these broad band high spectral resolution data. The radiated power in the atmospheric window from 771 to 981 cm−1was the first parameter chosen for fitting observed spectra. At succeeding levels of analysis the residual variability (observed spectrum minus best‐fit spectrum) in an ensemble of observations was partitioned into spectral eigenvectors. The eigenvector describing the largest fraction of this variability was examined for a strong spectral signature; the power in the corresponding spectral band was then used as the next fitting parameter. The measured power in nine spectral intervals, when it was inserted in the spectral fitting functions, was adequate to describe most spectra to within the noise level of Iris. Considerations of relative signal strength and scales of atmospheric variability suggest a combination sounder (multichannel, broad field of view) scanner (window channel, small field of view) as an efficient observing instrum

ISSN:0148-0227    

DOI:10.1029/JC080i015p01930

年代:1975

数据来源: WILEY

摘要:

The applicability of the existing spectral estimation methods is restricted to the stationarity conditions in a wave field. For nonstationary conditions a generalization of the conventional definition of spectrum as a distribution in both time and frequency suggests a filtering technique for spectral estimations. The statistical estimation errors associated with the general form of estimates are concisely described in a relative mean square error criterion. A minimization of this error as an overall figure of merit for the accuracy of estimates yields an optimal procedure for constructing an estimate that can be regarded as the most accurate one for the given physical wave data. Concepts are illustrated with actual wave data analysis, and the validity of the optimal procedure is demonstrated by simulation and comparison with the results from conventional techniques.

ISSN:0148-0227    

DOI:10.1029/JC080i015p01937

年代:1975

数据来源: WILEY

摘要:

A mechanical model is developed to describe the rafting of ice sheets of equal thickness. Rafting is one of the important deformation mechanisms in thin ice. The model predicts the force required to initiate rafting. This force is an upper bound for the force in pack ice. The model is also used to calculate the bending stress developed by rafting. The stress increases in proportion to the square root of ice thickness. Thus for a given ice strength there is a maximum thickness of ice which can raft without fracturing. For typical young ice properties the calculated value of 17 cm is in good agreement with field observation.

ISSN:0148-0227    

DOI:10.1029/JC080i015p01948

年代:1975

数据来源: WILEY

摘要:

Current measurements made in the Hudson Shelf Channel during the summer of 1973 show essentially channel axial bottom current even though the channel aspect ratio is small in the area of measurement. Although the current record is of short duration, correlation of water movement with surface winds is suggested by the data. The sense of summertime nontidal bottom flow in the channel (up or down channel) would appear to be controlled by the surface wind direction (offshore or onshore). These results would suggest the likelihood of net down‐channel flow during the summer month

ISSN:0148-0227    

DOI:10.1029/JC080i015p01953

年代:1975

数据来源: WILEY

摘要:

In recent trials near Hut Point Peninsula an impulse radar profiler was used successfully to monitor the depth characteristics and lateral extent of brine soaking in the McMurdo Ice Shelf. The success of the profiler can be attributed in large part to the significant difference in dielectric properties of dry firn and firn that has become brine soaked by infiltrating seawater. In addition to furnishing a continuous trace of the top of the brine layer, the impulse radar profiler has also revealed the existence of cracks, relict brine horizons, and deformational features within the ice shelf. Data tend to favor lateral infiltration of seawater, either through the seaward edge of the ice shelf or via tensile cracks at the bottom of the ice shelf.

ISSN:0148-0227    

DOI:10.1029/JC080i015p01957

年代:1975

数据来源: WILEY

摘要:

The space scales associated with the semidiurnal internal tides in the central Pacific are investigated by using time series of temperatures obtained from moored buoy arrays. Excellent phase coherence was found in the vertical from near the surface to depths exceeding 150 m. Phase coherence existed horizontally over distances of at least 5 but less than 50 km. With one exception the thermobaric energy associated with the semidiurnal tide showed no coherence in either the vertical (0–150 m) or the horizontal (5–500

ISSN:0148-0227    

DOI:10.1029/JC080i015p01962

年代:1975

数据来源: WILEY

摘要:

We have measured the internal wave field seaward of the continental shelf break off Vancouver Island, British Columbia, with an array of four moored temperature sensors and numerous STD casts. These measurements have been analyzed for their energy content at the semidiurnal tidal frequency, and the results compared with a theory of generation of internal tides at a shelf break. A peak in amplitude is observed at a depth slightly greater than that predicted by the theory. The observed phase change across this peak is consistent with seaward propagation of energy from the shelf break.

ISSN:0148-0227    

DOI:10.1029/JC080i015p01965

年代:1975

数据来源: WILEY

摘要:

Vertical propagation of near‐inertial period waves has been detected in a series of recent velocity profiles by a technique of vector spectral analysis. This method, previously applied to vector series in time, has been used to study the vertical spatial structure of velocity profiles obtained in the Mid‐Ocean Dynamics Experiment (MODE). Prior to the use of spectral analysis, however, it is necessary to minimize the influence of vertical variations of the Brunt‐Väisälä frequency. The procedure was to normalize the current amplitudes and stretch the vertical coordinate according to a WKB scheme. The vector spectral analysis, applied to the normalized and stretched profiles, yielded wave polarization estimates which are related to the sign of the vertical group velocity of internal waves. The analysis of a set of velocity profiles indicates that the net energy flux of the waves near the inertial frequency is

ISSN:0148-0227    

DOI:10.1029/JC080i015p01975

年代:1975

数据来源: WILEY

摘要:

A 2‐yr set of profile data from Torrey Pines Beach, California, measured at monthly intervals has been statistically analyzed by using empirical eigenfunctions. The analysis separates the temporal and spatial dependence of the data, this separation permitting beach changes to be described objectively by a linear combination of corresponding time and space functions. Most of the variation in profile configuration can be accounted for by three eigenfunctions corresponding to the three largest eigenvalues. The largest eigenvalue corresponds to an eigenfunction called the ‘mean beach function,’ which represents an average profile. A second eigenfunction, the ‘bar‐berm function,’ has a large maximum at the location of the summer berm and a minimum at the location of the winter bar, indicating its relation to the seasonal onshore‐offshore movement of sand. The third eigenfunction, the ‘terrace function,’ has a maximum at the location of the low‐tide terrace. Results of this study indicate that the eigenfunctions are useful in the analysis of beach profile data and provide objective insight into the nature of the variations of the pr

ISSN:0148-0227    

DOI:10.1029/JC080i015p01979

年代:1975

数据来源: WILEY