摘要:

Time‐height cross sections constructed from meteorological rocket data were studied to determine the time and height extent of the sudden warming of January 1963 over several stations. Circulation changes were evident at subtropical and midlatitude as well as subpolar stations. Wallops Island data indicated that the major region of warm air moved east and north of the station. There were indications that the wanning extended above 50 km and that its maximum intensity was near 40 km. Circulation features observed near 30 km were found to retain their identity above 50 k

ISSN:0148-0227    

DOI:10.1029/JZ069i002p00201

年代:1964

数据来源: WILEY

摘要:

From the beginning of the century the seasonal variation of the sea‐surface temperature and the superincumbent air over the Arabian Sea and the Bay of Bengal have been studied from decade to decade. The amplitude of the annual wave is generally higher for air temperature than for sea‐surface temperature. Larger amplitudes of the annual waves are associated with the earlier occurrence of the maximum in the wave. A general tendency for an earlier occurrence of the maximum in the annual wave of both air and sea‐surface temperatures was observed. The available data on pressure and relative humidity have also been studied. All the data have been utilized in estimating the evaporation over the sea areas under consideration, and an increase of evaporation has been no

ISSN:0148-0227    

DOI:10.1029/JZ069i002p00215

年代:1964

数据来源: WILEY

摘要:

During the 28‐month interval from September 1960 through December 1962, drift bottles were released periodically from a stationary platform located 20.4 km offshore from Panama City, Florida. Of the 951 bottles released, 276, or 29 per cent, were recovered. Approximately 67 per cent of the returns have been found along a 350‐km section of coastline extending from Cape St. George west to the Florida‐Alabama line; 20 per cent of the returns were from the Florida east coast and keys, and 12 per cent were found along the coasts of Alabama, Mississippi, Louisiana, and Texas. Comparison of the drift‐bottle data with local wind information indicates that the primary mechanism of surface water transport in the vicinity of the release point is wind‐induced currents, which either transport the bottles to local beaches or to regions where permanent or semipermanent currents can displace them to western or southern shores. The results of this study are also compared with other drift‐bottle studies conducted in the Gul

ISSN:0148-0227    

DOI:10.1029/JZ069i002p00223

年代:1964

数据来源: WILEY

摘要:

Echo sounding records taken in the Blake‐Bahama basin near 26°00′N, 76°10′W show crescents later than the main bottom reflection. The crescents are interpreted as diffraction arrivals from a corrugated bottom. The mean distance between corrugation crests is estimated to be 120 meters. The crests are in a N‐S direction. The depth to bottom is about 47

ISSN:0148-0227    

DOI:10.1029/JZ069i002p00231

年代:1964

数据来源: WILEY

摘要:

Samples of powdered silicates have been sifted in a vacuum chamber at pressures of 10−10, 10−9, and 750 mm Hg. The geometry of the deposit and the force necessary to disrupt it both implied cohesion of particles under high‐vacuum conditions. If the attractive forces act only at points of contact in an array of elastic spherical particles, a contact stress of 3 × 108dynes/cm2would explain the observed cohesion. If, on the other hand, the forces act over a distance rather than at contact points, then the analysis depends upon a major portion of the surface area being covered by the powder deposit. The cohesion for this case is estimated to be 750 dynes/cm2. These data indicate that lunar surface materials will exhibit an appreciable shear strength, so that disastrously low bearing capacities need not be expected. The lack of adhesion in air, and after contamination of the particles with a monolayer of oil, suggests that van der Waal's forces and/or ionic and covalent bonds rather than gross electrostatic forces are probably responsible for high‐vacuum

ISSN:0148-0227    

DOI:10.1029/JZ069i002p00235

年代:1964

数据来源: WILEY

摘要:

The theory makes use of three distinct idealized models. The general equations of motion are derived for a continuum model. This continuum consists of three components—a solid, a gas, and a liquid; the liquid adheres to the solid and has surface tension. The elastic coefficients occurring in the equations of motion are determined for a model consisting of randomly stacked spheres of different sizes; the interstices of this model contain both gas and liquid. The dissipation coefficients occurring in the equations of motion are determined for a model of short capillary tubes. The nine equations of motion are transformed into rotational and irrotational equations to yield plane, progressive, sinusoidal waves. The wave velocity and the attenuation are derived for the asymptotic cases of very low and very high frequencies. It is proved that there are three types of compressional waves and one type of shear wave. At very low frequencies only one type of compressional wave prevails, and at very high frequencies the dissipation for all four types of waves is proportional to the square root of the frequenc

ISSN:0148-0227    

DOI:10.1029/JZ069i002p00243

年代:1964

数据来源: WILEY

摘要:

The well‐fracturing operation is modeled by a band of uniform pressure and two bands of uniform shear stress acting in a cylindrical cavity in an infinite body. Two interesting regions of induced stress are: either end of the pressurized interval where the tangential stress is zero (the vertical stress is approximately 95 per cent of the pressure) and the center of the packed‐off interval where the tangential stress equals the pressure (the vertical stress is zero). The tectonic stresses are the overburden load and two unknown principal horizontal stresses that cause easily determined stress concentrations at the well bore. All calculated stresses are modified to account for the interstitial pore‐fluid pressure. It is found that three situations are of interest: (1) the induced vertical stress is less than the overburden pressure; (2) the induced vertical stress and the instantaneous shut‐in pressure are greater than the overburden pressure; (3) the induced vertical stress is greater than the overburden pressure but the instantaneous shut‐in pressure is less than the overburden pressure. In (1) the fracture is vertical and the stresses are determinable. In (2) the fracture is horizontal and the stresses are indeterminate. In (3) the fracture is initially horizontal but becomes vertical as it propagates away from the well, the vertical and minimum horizontal compressions are determinable, and the other principal stress is bounded by a set of inequalities. Several examples are presented in which the tectonic stress states appear to be relaxed—approximately equivalent to the ‘hydrosta

ISSN:0148-0227    

DOI:10.1029/JZ069i002p00259

年代:1964

数据来源: WILEY

摘要:

Approximate reflection coefficients have been obtained by a Green's function technique for Love waves normally incident upon the corner of a wedge formed by two stress‐free planes. The incident waves travel in a layered medium with structure parallel to one of the faces of the wedge. The approximation yields the exact reflection coefficient for wedge angles of π and

ISSN:0148-0227    

DOI:10.1029/JZ069i002p00275

年代:1964

数据来源: WILEY

摘要:

A Green's function method has been used to compute approximate values for the complex transmission and reflection coefficients for Rayleigh waves normally incident upon the corner of an homogeneous elastic wedge formed by two stress‐free planes. Numerical values of the transmission and reflection coefficients have been computed as a function of Poisson's ratio and the angle of the wedg

ISSN:0148-0227    

DOI:10.1029/JZ069i002p00281

年代:1964

数据来源: WILEY

摘要:

The frequency‐independent transmission and reflection coefficients for two‐dimensional Rayleigh waves incident upon a corner have been measured experimentally as a function of angle. The coefficients were obtained by Fourier analysis of pulses observed in a laboratory model. The amplitude valuesATandARare in agreement with previous experimental evidence. The phase shifts account for wave‐shape changes noted previously. The experimental values show fair agreement with first‐order theory for angles between 110° and 180°. For smaller angles interference occurs which is not adequately explained by the first‐o

ISSN:0148-0227    

DOI:10.1029/JZ069i002p00291

年代:1964

数据来源: WILEY