摘要:

Results from three balloon flights undertaken in July 1965 to measure the microwave emission by molecular oxygen are presented. The first experiment measures the resonance line shape in the atmosphere, and the other two make measurements that can be used to infer the temperature profile of the atmosphere below the balloon. The line shape experiment makes observations at two zenith angles (60° and 75°) and at three frequencies (±20, ±60, ±200 MHz) centered on the 9+resonance line at 61.151 GHz. The results of this flight confirm the validity of the VanVleck‐Weisskopf line shape for the conditions of the experiment. This result contradicts results from our earlier experiments, which used an incomplete antenna pattern in the theoretical computations. Revised theoretical computations for one of these earlier flights are in agreement with the measurements, for further confirmation of the line shape. The temperature profile experiments make measurements in the same frequency ranges but observe at two nadir angles (0° and 60°) to view the atmosphere below the balloon rather than above it. These measurements are also in agreement with theoretical computations to within the uncertainties of the ex

ISSN:0148-0227    

DOI:10.1029/JB073i004p01119

年代:1968

数据来源: WILEY

摘要:

A raft‐mounted photographic system was devised to sample large (radius>45 μ) spray droplets at an altitude of 13 cm above the sea surface. Aboard the same raft the wind was measured at an elevation of 47 cm and salt was collected at several elevations in the lowest 1.2 meters. The spray droplet concentration shows an abrupt increase as the wind increases from about 8.5 to about 9.5 m/sec. This result is consonant with the reported observations of ‘critical’ or ‘transition’ velocities in numerous other sea‐surface and near‐sur

ISSN:0148-0227    

DOI:10.1029/JB073i004p01127

年代:1968

数据来源: WILEY

摘要:

Thirty‐two samples of atmospheric molecular hydrogen, collected at Oberhausen and München, Germany, between 1958 and 1963 have been analyzed for their tritium and deuterium content. The procedure for extracting the hydrogen from the crude neon fraction from air liquefaction plants is described in some detail. Data indicating good reproducibility are given. Where possible the results are compared with results obtained on the same samples in other laboratories. Reasons for discrepancies, which in some cases amount to 50%, are discussed. During the 1958–1961 test moratorium on thermonuclear weapons the tritium level continued to rise; yet, no immediate significant increase due to the large USSR test series at the end of 1961 has been obse

ISSN:0148-0227    

DOI:10.1029/JB073i004p01139

年代:1968

数据来源: WILEY

摘要:

Ten samples of atmospheric methane collected at Oberhausen, Germany, and Gary, Indiana, between 1960 and 1963 have been analyzed for their tritium and deuterium content. The results show the tritium concentration in the northern hemisphere to have been essentially constant since 1958, the time the first samples were analyzed. Existing theories to explain the origin of tritiated methane are discussed and rejected as highly improbable. The data can best be explained by assuming that leakage of tritiated methane into the atmosphere from sources in nuclear industry located in the northern hemisphere occurred for a period of years prior to 1958, and then the leak was essentially closed.

ISSN:0148-0227    

DOI:10.1029/JB073i004p01149

年代:1968

数据来源: WILEY

摘要:

Atmospheric concentrations of radon, calculated from filtered radon daughter β‐activity and corrected for radioactive equilibrium departure, were obtained from three sites in the Washington, D.C., area. Measurements made at various heights above ground up to 91 meters yield diurnal, seasonal, and annual mean radioactivity concentrations and their relationship to meteorological variables. These data indicate that the horizontal distribution of radon is homogeneous during much of the midday period. Radon measurements over a distance of about 40 km suggest that the urban area does not act effectively as either a source or sink for radon. On the basis of derived atom concentration ratios (ρ = Bi214/Pb214), radon is near secular equilibrium with its daughter products in the air; the major departure from equilibrium occurs during atmospheric stability and near the ground. Analyses of the temporal‐spatial variations of atmospheric radioactivity indicate that the variation in the concentration of radon at a given height above the ground is mostly a consequence of atmospheric dilution, specifically, vertical mixing; the effects of advection, changes in emanation rates, and various scavenging processes are slight (except for relatively short time‐space dimensions) relative to the effects of vertical

ISSN:0148-0227    

DOI:10.1029/JB073i004p01155

年代:1968

数据来源: WILEY

摘要:

Samples of liquid oxygen collected at ground level near Neosho, Missouri, have been processed for recovery of methane, and the tritium content of these samples has been measured. The fluctuation of the T/H ratio in these samples is discussed in terms of possible sources of this radioactivity. Arguments that this tritium‐labeled methane has been released from sources in nuclear industry are supported by measurements of tritium in ethane recovered from some of these liquid oxygen samples. The continuing release of labeled methane by nuclear industry is suggested by the fact that the T/H ratio has not changed appreciably during the period 1958 to 1966, although this interval is comparable to the chemical lifetime expected for methane in the atmospher

ISSN:0148-0227    

DOI:10.1029/JB073i004p01167

年代:1968

数据来源: WILEY

摘要:

The electric field changes caused by identified cloud and ground lightning flashes have been analyzed in terms of their more conspicuous features, in particular, duration, over‐all magnitude, number and size of steps, and presence and maximum slope of ramps. Plots of field change against distance showed reasonable agreement with the inverse cube law, which has been used for normalizing field changes of flashes at various distances between 3 and 20 km. Statistical distributions of the measurements were used as a basis for comparing the field changes of ground and cloud flashes; it was observed that impulsive discharges occurred in both but were more frequent and caused larger field changes in ground flashes than in cloud flashes. Furthermore, flashes in the upper part of the thundercloud involved fewer impulsive discharges than cloud flashes about cloud base level, suggesting that height in the thundercloud influences the mode of discharg

ISSN:0148-0227    

DOI:10.1029/JB073i004p01175

年代:1968

数据来源: WILEY

摘要:

The distribution in time and space of C14from the 1961–1962 nuclear weapons tests of the U.S. and the USSR is used as a tracer for atmospheric mixing phenomena and exchange of carbon dioxide between the atmosphere and the sea. The mean residence time of C14injected into the stratosphere by the tests or produced by cosmic rays is about 1.5 years before entering the troposphere. The C14enters the troposphere predominantly at midlatitudes in the late spring. Dispersion of the C14injected into the troposphere is well accounted for by eddy diffusion, with the meridional eddy diffusion coefficients being proportional to the variance of the meridional component of the wind speed. Exchange of carbon dioxide between the atmosphere and the sea (and therefore uptake of excess C14by the sea) is taken to be proportional to the square of the average wind speed over the sea surface. This leads to the conclusion that the bulk of the C14will eventually be taken up by the oceans of the southern hemisphere. A mean residence time of 2.5 years for a carbon dioxide molecule in the troposphere before uptake by the sea is deduced from the model, giving a mean residence time of 4 years for a C14atom in the atmosphere before uptake by the se

ISSN:0148-0227    

DOI:10.1029/JB073i004p01185

年代:1968

数据来源: WILEY

摘要:

An inexpensive video contouring device for weather radars is described. Its small size, stability, ease of calibration and multiple‐level capabilities overcome some of the obvious shortcomings of earlier circuits. Data have been collected on a variety of weather situations including easterly waves, cold‐frontal squall lines and hurricanes using the device. Examples are taken from hurricane Inez and cold fronts to substantiate the contention that the relatively simple methods used can provide significant improvements in quantitative precipitation measurements with standard PPI scope photogra

ISSN:0148-0227    

DOI:10.1029/JB073i004p01201

年代:1968

数据来源: WILEY

摘要:

The heat‐energy transfer through a four‐layer system of air, snow, sea ice, and sea water is determined numerically, and the optical, thermal, and composition properites of the solid layer are discussed. The annual sea ice investigated was close to the Australian National Antarctic Research Expedition station of Mawson. The observation was made over a period of five months from the middle of June to the middle of November 1965. Net long‐wave radiation losses through the surface of the sea ice are high to balance a large heat flux from the water below; they exceed 140 cal cm−2day−1in November. The disappearance of the snow cover over the ice in summer results in a drop of the albedo from 75 to 37% and allows a large amount of short‐wave radiation to be absorbed by the ice. This results in changes in heat storage in the ice and a considerable increase of the conducted heat flux at the upper boundary as summer approaches. It is shown that consideration of the effects of absorbed radiation is essential in heat budget studies in transparent bodies of finite thickness. Idealized curvature characteristics of measured wind and temperature profiles are used over the sea ice to compute the eddy heat flux, with neutral or near‐neutral stability representing the average condition. The aerodynamic roughness parameterz0is computed to have a mean value of 0.013 cm and little variation with wind speed. The latent heat flux at the upper boundary and eddy heat flux at the lower boundary are treated as remainder terms in the energy balance equation. Advection of heat by water currents is considered, and error estimates of the heat budget components are discussed. The heat exchange between the sea ice and the atmosphere is compared with the heat exchange between an ice‐free ocean surface and the atmosphere and is found to be an order of ma

ISSN:0148-0227    

DOI:10.1029/JB073i004p01209

年代:1968

数据来源: WILEY