摘要:

Quantitative measurements of Raman scattering intensities from N2, O2, and CO2under ambient atmospheric conditions are given. The atmosphere was illuminated with 20,489 cm−1Ar+laser radiation. These scattering intensities are sufficiently strong to allow measurement of O2/N2and CO2/N2concentration ratios in the atmosphere to a precision of 0.3 and 0.006 ppm total atmosphere, respectively, by means of scattered photon counting over a 174‐hour integration period. The Raman technique represents an improvement in precision over existing techniques by almost two orders of magnitude, and a substantial but less easily determined improvement in accuracy by using the transition probabilities of a monomolecular reference gas as a standard, rather than the properties of a mixed gas standard as is done in current measureme

ISSN:0148-0227    

DOI:10.1029/JC075i009p01629

年代:1970

数据来源: WILEY

摘要:

In several extreme cases, analytical expressions for collision efficiencies are derived. They are used as a basis for empirical approximation formulas of collision efficiencies obtained by numerical integration of droplet trajectories. Approximation formulas, restricted to the case in which no external electric fields are present, are given for collisions between droplets ≤20 μ in radius, carrying an average surface charge density ≥0.16 esu/cm2, and collisions between large drops (radius ≥500 μ) and small droplets (radius ≥2 μ). Approximation formulas for collision efficiencies between large charged drops in the 100‐ to 1000‐μ radius range include vertical

ISSN:0148-0227    

DOI:10.1029/JC075i009p01633

年代:1970

数据来源: WILEY

摘要:

The variation of stratospheric turbidity in recent years in midlatitudes and in the tropics as indicated by the amplitude of the λ715/477 or λ810/500 color ratio of twilight radiance at 20° elevation is investigated. Since late 1963, the stratospheric turbidity in northern mid‐latitudes has been much higher than it was before the explosion of the Agung volcano in March 1963; a considerable latitude effect is indicated. In the tropics, the stratospheric dust layer was even stronger (and at a greater altitude) in 1969, and very likely was also stronger during the preceding years. There is not much direct evidence that the apparently persistent, yet abnormal, tropical reservoir of stratospheric aerosol was replenished by more recent volcanic acti

ISSN:0148-0227    

DOI:10.1029/JC075i009p01641

年代:1970

数据来源: WILEY

摘要:

A turbulent flow field that permits study of the kinematics of individual suspended particles has been produced in the laboratory. This paper considers the behavior in the vertical direction of particles 2 mm in diameter that have still‐water terminal settling velocities ranging up to 4.0 cm/sec. The particle velocity frequency distributions are approximately Gaussian, and their root‐mean‐square values prove to be nearly independent of terminal fall velocity. In the majority of cases, particle diffusivity is greater than fluid diffusivity. The average velocity of fall determined by experiment in the various turbulent fields is reduced by as much as 30% below the corresponding still‐water terminal fall velocity. A simple theoretical model predicts the fall velocity reduction due to a nonlinearity in the drag force. The model is then extrapolated to describe the behavior of quartz sand under field‐scale turbulence conditions. It also predicts the time and distance required for such sand to reach terminal fall velocity in st

ISSN:0148-0227    

DOI:10.1029/JC075i009p01647

年代:1970

数据来源: WILEY

摘要:

Reflection profiles and hydrographic data indicate that sedimentation in parts of the northernmost Atlantic and in the Labrador basin has been largely governed by the movement of bottom water derived from the Norwegian Sea. Three areas are considered in detail. The first is the channel separating Rockall bank from the Irish continental shelf, where a ridge, nearly 600 km long, composed of sediment deposited on a gently dipping reflector of early Tertiary age, has been found. Hydrographic observations suggest that the feature, for which the name Feni ridge is proposed, is the result of deposition close to the boundary of a component of the Iceland‐Scotland overflow water from the Norwegian Sea, which enters the channel from the north and in flowing southward is constrained by Coriolis force to the Rockall scarp. Farther north, reflection profiles show a marked asymmetry of sediment distribution across the volcanic Faeroe‐Iceland ridge, the sediment cover being much thicker and more continuous on the north‐facing slope than on the crest and southern flank. This difference is attributed to fast bottom currents in the south, caused by sinking of the Norwegian Sea overflow, and the persistence of tranquil bottom conditions in the north. Seismic profiles from the Labrador basin reveal a well‐defined body of thick sediments trending NNW on a portion of the continental rise of southern Greenland where turbidity currents cannot reach. The thick sediments lie in a region in which the flow of deep water is weak and in which rapid deposition from sediment‐laden bottom waters is allowed. Appreciably stronger bottom currents associated with the counterclockwise circulation of dense water derived from the Norwegian Sea appear to have greatly inhibited deposition of pelagic material in the area surrounding the sediment body. Sedimentation under the influence of bottom currents in this region, in the Rockall area, and on the Blake‐Bahama outer ridge took place throughout a large part of Tertiary time but did not occur in the Upper Cretaceous. This is attributed to a major alteration in the circulation pattern of the North Atlantic caused by continental drift, polar wandering, and climatic deterioration between late Cretaceous and late E

ISSN:0148-0227    

DOI:10.1029/JC075i009p01655

年代:1970

数据来源: WILEY

摘要:

Waves of large amplitude may form spilling breakers over a very gentle slope. A theoretical and experimental analysis of such waves is presented. In particular, the rate of energy dissipation as a function of bottom slope and convergence of wave orthogonals is determined theoretically and experimentally and related to the relative height of foam “white water” appearing in front of the breaker. Also the velocity field in gentle spilling breakers is measured. It was found that, except near the crest, the major features are essentially those of a limit height nonbreaking w

ISSN:0148-0227    

DOI:10.1029/JC075i009p01681

年代:1970

数据来源: WILEY

摘要:

An experiment for the measurement of vertical distribution of ozone in the subpolar region was made at Fort Greely, Alaska (64°N). Two rocket‐borne ozonesondes and two balloon‐borne Mast electrochemical ozonesondes were flown during the last week of December 1968. The results show large variations with altitude in the ozone concentration in the lower stratosphere and more ozone than theorized near 40 km. There is no indication of any significant diurnal variation in the ozone concentration in the upper stratosp

ISSN:0148-0227    

DOI:10.1029/JC075i009p01693

年代:1970

数据来源: WILEY

摘要:

In a recent paperAnderson and Freier[1969] presented a mathematical model of a thunderstorm in a conducting atmosphere whose conductivity increases exponentially with altitude. Because of the difficulty of the model, no exact solutions were given but approximate solutions were provided for the caseTc(their notation will be followed exactly) large andTcsmall. Anderson and Freier call attention to the fact that in many casesTcis neither large nor small. Our purpose is to show that all problems of the type considered can be solved by separation of variables and that solution of the problem with exponentially varying conductivity can be expressed in terms of hypergeometric functions.

ISSN:0148-0227    

DOI:10.1029/JC075i009p01697

年代:1970

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JC075i009p01699

年代:1970

数据来源: WILEY

摘要:

The Symposium on Atmospheric Trace Constituents and Atmospheric Circulation, held in Heidelberg, Germany, September 8–13, 1969, was organized by the Commission on Atmospheric Chemistry and Radioactivity of the International Association of Meteorology and Atmospheric Physics. The symposium was sponsored jointly by the World Meteorological Organization and IAMAP. The University of Heidelberg was host organization. More than 100 scientific papers were presented in symposium sessions on the following topics:A. Tracers and Transport ProcessesB. Radioactive Aerosol Transport and FalloutC. Radiocarbon and Tritium DistributionD. Aerosol Formation and Removal ProcessesE. Atmospheric Trace Gas DistributionF. Aerosol Distribution and CompositionG. Upper Atmosphere ConstituentsH. Atmospheric GeochemistryI. Emanations and Daughters as TracersJ. Air and Precipitation ChemistryK. Cosmogenic Radioisotopes as Trace

ISSN:0148-0227    

DOI:10.1029/JC075i009p01700

年代:1970

数据来源: WILEY