摘要:

The radar cross section at 3.2 cm exhibits a systematic temperature dependence of sufficient magnitude to warrant consideration in the computation of backscattering cross sections. The ratio of Mie to Rayleigh scattering cross sections can be represented quite accurately by an eighth‐degree polynomial for 3.2‐cm radiation and by a second‐degree polynomial for 10.3‐cm radiation. These formulas permit an explicit functional representation of unit‐volume radar reflectivity for all suitably integrable distributions. The scattering properties of various distributions may then be determined with minim

ISSN:0148-0227    

DOI:10.1029/JZ069i014p02873

年代:1964

数据来源: WILEY

摘要:

Sodium, manganese, and bromine in local atmospheric aerosols have been measured each weekday for a period of about three months by the method of neutron activation analysis. The technique used requires no radiochemical treatment of the samples. Histograms of the results obtained show the following concentrations most frequently measured: 0.10 μg/m3of sodium, 0.03 μg/m3of manganese, and 0.10 μg/m3of bromi

ISSN:0148-0227    

DOI:10.1029/JZ069i014p02881

年代:1964

数据来源: WILEY

摘要:

Spectrum analysis of the mean monthly zonal winds at 50 mb indicates energy peaks near 24‐, 12‐, 8‐, and 6‐month periods. However, an analysis of the mean biennial and annual waves shows that the observed annual spectral peak is made up of harmonic energy from the 26‐month wave plus energy of the annual variation itself. The 8‐month wave peak can be totally explained as the third harmonic contribution of the biennial wave. The 6‐month peak appears to contain harmonic energy from both the biennial and

ISSN:0148-0227    

DOI:10.1029/JZ069i014p02887

年代:1964

数据来源: WILEY

摘要:

During the summer of 1962 the potential gradient was measured at Mercury, Nevada, as a function of height above ground level. At the earth's surface the value was +30 v/m; this rose steadily with altitude to reach a maximum of +110 v/m at a height of about 1200 m. The interpretation of these results suggests that the surface γ‐ray activity for areas adjacent to atomic weapon test sites in Nevada is perhaps ten times the normal backgrou

ISSN:0148-0227    

DOI:10.1029/JZ069i014p02895

年代:1964

数据来源: WILEY

摘要:

Investigations of temperature inversions obtained from bathythermograph soundings in the Pacific revealed that inversions 0.50C or larger occur not only in polar regions but also in the subtropics and tropics. Such inversions are usually not associated with any static instabilities. The processes leading to the formation of the temperature inversions differ in different latitudes and under different flow conditions. In polar regions radiative and evaporative cooling appears to be the chief process; in subtropical latitudes inversions seem to be mostly due to differential advection of water of different origin. Inversions in the region of the jetlike countercurrents and undercurrents occur within the layer of strong velocity shear and may be due to turbulence. The largest temperature inversions, about 4°C, are found to occur near the Kuroshio‐Oyashio boundary off northern Japan. Observations at fixed points indicate that the time variations of the intensity of the inversion and of the depth and vertical extent of the temperature maximum are of the same order of magnitude for hourly, daily, and monthly time scales. Several theoretical models are discuss

ISSN:0148-0227    

DOI:10.1029/JZ069i014p02899

年代:1964

数据来源: WILEY

摘要:

In the theoretical considerations presented by Roden certain simplifications can be made if the horizontal part of the flow is regarded as geostrophic. If this is the case, the vertical shear of the current is given by∂VH∂z=−gρfk×∇Hρwhere ρ is the density at constant pressure (mT+nS),fis the Coriolis parameter,gis the gravity field strength, andkis the vertical unit vector. In (7) and (9) of Roden's paper the term (∂VH/∂z)·∇Hρwill then vanish since ∂VH/∂zis perpendicular to∇H∂. It will have nonzero value only if friction or inertial effects (nongeostro

ISSN:0148-0227    

DOI:10.1029/JZ069i014p02915

年代:1964

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JZ069i014p02917

年代:1964

数据来源: WILEY

摘要:

A total of 166 dust particles collected principally from Greenland and antarctic ice has been subjected to chemical analysis by the electron‐beam microanalyzer technique. Several have Ni/Fe ratios indicative of a meteoritic origin. The remainder are probably also primarily cosmic in origin. The rate of deposit of opaque spherules is found to be nearly, but not exactly, the same at all geographical locations sample

ISSN:0148-0227    

DOI:10.1029/JZ069i014p02919

年代:1964

数据来源: WILEY

摘要:

It is well known that the earth's surface heat flow is in approximate balance with the heat production in an earth of chondritic composition. The ratio of K/U in crustal rocks and peridotite, dunite, and eclogite is about 1×104, in contrast to the ratio in chondrites of about 7.5×104. The present computations show that earth models having a U concentration 3 or 4 times that observed in meteorites and with K/U = 104yield the observed heat flow, provided that the initial temperature was of the order of 1000°C or less. In the models, the ratios of K/U and Th/U are assumed constant throughout the earth and equal to 1×104and 3.7, respectively. Three radial distributions of radioactive material are studied: (1) uniform distribution in mantle, (2) oceanic structure with radioactive material in the upper 1500 km and a concentration above 465 km, (3) continental structure with radioactive material above 1500 km and a marked concentration in the upper 45 km. The oceanic and continental models give the observed heat flow provided that the average U concentration of the mantle lies between 4 and 5× 0−8g g−1and the initial temperature at depth was 1000°C. An average mantle concentration of U of about 5.5×10−8g g−1will produce melting in the upper mantle and a heat flow in excess of that observed. With these structures, the calculations clearly show that the present heat flow implies melting at depth unless the thermal conductivity increases substantially with depth. The problems of the development of the initial temperature gradient and of the nonradioactive heat sources r

ISSN:0148-0227    

DOI:10.1029/JZ069i014p02933

年代:1964

数据来源: WILEY

摘要:

Numerical calculations have been made that determine the equation of state of the materials which constitute the mantle and core of the earth. These calculations are based on the observed seismic velocities and the known mass and moment of inertia of the earth. Comparison of these equations of state with those obtained experimentally indicate the type of materials which may exist in the various regions. The general features of these calculations are in close agreement with the conclusions reached by F. Birch and others; namely, the mantle is made up of high‐density oxides of silicon, iron, and magnesium, and the core is mostly iron. Density and pressure variations throughout the earth are also obtaine

ISSN:0148-0227    

DOI:10.1029/JZ069i014p02947

年代:1964

数据来源: WILEY