摘要:

A five‐channel microwave spectrometer operating near the 1.35‐cm wavelength water vapor and the 5‐mm wavelength oxygen resonances was flown in the NASA Convair 990 aircraft at altitudes near 12 km and used to infer layer thicknesses and water vapor and liquid water abundances in the troposphere. The calibration of the spectrometer and a multiple regression method of interpretation of the data obtained from the flights are described. Possible errors from clouds and from the terrestrial surface are discussed. Values of atmospheric layer thicknesses, water vapor content, and liquid water content inferred from microwave data obtained over two frontal systems are presented. The inferred values of 1000‐ to 500‐mb and 500‐ to 250‐mb thicknesses agree with directly measured values to within 15 meters at the places where the direct measurements were made. This agreement is equivalent to errors of<1°K in me

ISSN:0148-0227    

DOI:10.1029/JC077i030p05833

年代:1972

数据来源: WILEY

摘要:

A series of electrostatic field measurements were made in the vicinity of nuclear explosions on the Nevada Proving Ground of the Atomic Energy Commission in 1952. Detonations with energy yields in the 20‐kT range produced electric dipoles with the negative charge uppermost and with moments of a few coulomb kilometers. The electrical field produced by the nuclear cloud could be observed for several minutes after the explosion while the cloud moved upward through the troposphere to the vicinity of the tropopause. The estimated magnitude of the dipole moment of the cloud increased for several minutes as it moved upward. The results of the tests are in qualitative agreement with a γ‐ray‐Compton electron model of charge separation. Difficulties associated with quantitative predictions of the model are discussed. The passage over the instruments of a weakly radioactive cloud from the stem of the mushroom cloud in one test produced results that are interpreted as a perturbation of the normal air‐earth curren

ISSN:0148-0227    

DOI:10.1029/JC077i030p05845

年代:1972

数据来源: WILEY

摘要:

Characteristics of the electrification in dust storms have been studied by making field observations at different places in the southwestern United States. Measurements consisted of the atmospheric electric potential gradient at ground level, space charge and wind speed (both at 1.25 meters above the ground), atmospheric temperature and relative humidity, and size distribution of dust particles at ground level. It has been observed that during dust storms both signs of potential gradient can occur at ground level, and any sign of potential gradient can be associated with the same or opposite sign of space charge at 1.25 meters above the ground. Potential gradients of many kilovolts per meter are not uncommon during these dust storms, and sometimes these high values can be sustained for many minutes, The space charge values at 1.25 meters above the ground associated with these high values of potential gradient can be as high as 105–106el cm−3. In some dust storms the polarities of potential gradient and space charge have been observed to change if the blowing dust, rather than reach high altitudes, is raised because of low wind speeds only to lower levels. Size distributions of different types of dust particles collected at ground level are also gi

ISSN:0148-0227    

DOI:10.1029/JC077i030p05856

年代:1972

数据来源: WILEY

摘要:

Laboratory energy and mass flux results of Mangarella et al. (1971) are compared with field data cited by Monin (1970). Acceptable agreement exists for Reynolds numbersu*z0/ν ≥ 1, the predominant laboratory regime. A variety of flux prediction equations are examined for the laboratory data. Kitaigorodskii and Volkov's theory and Sverdrup's theory (with a constant diffusion thickness of 0.05 cm) show agreement with the measured fluxes. In general, the theories incorporating some type of diffusion layer hypothesis appear to be more appropriate. Reynolds analogy is shown to be applicable only for low roughness Reynolds number flo

ISSN:0148-0227    

DOI:10.1029/JC077i030p05870

年代:1972

数据来源: WILEY

摘要:

The unattached positively charged daughter products of222Rn in laboratory air relatively free of condensation nuclei have been investigated by deposition on aluminium foils in an electric field. The rate of decay of the α activity deposited on the foils at various critical mobilities indicates relative concentrations of218Po,214Pb, and214Bi ions in the ratio 1∶1.5∶0.2 independent of the mobility of the ions collected. A normalized activity characteristic is constructed from the distribution of activity along the strips of foil at various critical mobilities. The mobility distribution, obtained from the second derivative of the characteristic, ranges from 0.3 × 10−4m2v−1sec−1to 3 × 10−4m2v−1sec−1, the mean value being 0.

ISSN:0148-0227    

DOI:10.1029/JC077i030p05876

年代:1972

数据来源: WILEY

摘要:

The behavior of222Rn daughter ions in fair weather and thunderstorm environments has been investigated numerically. One‐dimensional time‐dependent differential equations for radioactive ions employed in the numerical model involve, in addition to the usual terms for radioactive decay and eddy diffusion, terms for ion attachment and recombination, electric field, and vertical wind. Numerical and experimental results are compared to show the applicability of the model to predictions of the behavior of222Rn daughter ions in different atmospheric conditions. Eddy diffusion affects concentrations of both222Rn and its daughter ions similarly and produces changes in their concentrations of the order of 10 in a diurnal period. Inclusion of the term for the vertical wind in the differential equations for both222Rn and its daughter ions produces similar changes in both concentrations. In contrast to eddy diffusion and the vertical winds, attachment and ion migration due to electric fields such as those existing during thunderstorms affect solely the concentration of radioactive ions. These effects are shown to be the dominant ones under certain meteorological conditions. A change in the concentration of the condensation nuclei from 104to 105nuclei/cm3increases ion attachment and causes a reduction by a factor of about 7 in the concentration of radioactive ions. Under thunderstorm conditions withEof the order of 100 volts/cm the reduction in ion concentration close to the ground is of the order of 8 or more, owing to upward migration of radioactive ions. The numerical solutions for radioactive ions show that the migration effect producing a decrease in the concentration of radioactive ions can be observed up to 50 meters above the ground, beyond which the concentrations approach the values for fair weather. The recombination effect is negligible, since a change inn−from 550 to 2750 ions/cm3causes a decrease of only about 3% in the concentration of radioactive

ISSN:0148-0227    

DOI:10.1029/JC077i030p05883

年代:1972

数据来源: WILEY

摘要:

A theoretical expression is derived from the heat‐flux conservation equation for the counter potential‐temperature gradient that can sustain an upward flux of sensible heat. This gradient is found to be γc= (g/θ) 〈θ′2〉/〈w′2〉, where 〈θ′2〉 is the potential temperature variance and 〈w′2〉 is the vertical velocity variance. The usual down‐gradient eddy coefficient expression for the heat flux is obtained from the derivation only if γcis set to zero. Aircraft measurements of (g/θ) 〈θ′2〉/〈w′2〉 in the middle and upper portions of convective planetary boundary layers indicate that this expression for γcis of the same order of magnitude (near 0.7 × 10−5°K cm−1) as the value deduced pr

ISSN:0148-0227    

DOI:10.1029/JC077i030p05900

年代:1972

数据来源: WILEY

摘要:

The rate of formation of sulfate ion in raindrop size distilled water drops was measured for partial pressures of SO2ranging from 10−6to 4 × 10−3atm. A model was developed based on the results and on the assumption that the rate of formation of sulfate is determined by the rate of the first dissociation of sulfurous acid and by the rate of oxidation of sulfite to sulfate. The results of the model agree with published data for the rate of solution of SO2at low partial pressures. The model was applied to rainout and washout of SO2by cloud and raindrops. The contribution of the sulfate formed by gaseous absorption to the sulfate content of rain water was calculated. This contribution is important in polluted areas, although it is not predominant. It is also shown that fog droplets, after absorbing SO2in relatively polluted areas, produce particles of cloud nucleus size by evapora

ISSN:0148-0227    

DOI:10.1029/JC077i030p05905

年代:1972

数据来源: WILEY

摘要:

The two‐scale (small irregularities superimposed on large undulations) scattering theory proposed by Semyonov has been extended and used to compute the microwave apparent temperature and the backscattering cross section from ocean surfaces. The effect of the small irregularities on the scattering characteristics of the large undulations is included by modifying the Fresnel reflection coefficients, and the effect of the large undulations on those of the small irregularities is accounted for by averaging the scattering cross sections of the small irregularities over the surface normals of the large undulations. The same set of surface parameters in the assumed scattering model is employed at a given wind speed to predict both the scattering and the emission characteristics for both polarizations. Much improved agreement with measured results over a single‐surface theory is demonstrated. This agreement indicates that the sea surface is better modeled by a composite than by a single surface. The result also indicates that the adequacy of a scattering model is better exemplified when it is used to predict both the scattering and the emission characterist

ISSN:0148-0227    

DOI:10.1029/JC077i030p05917

年代:1972

数据来源: WILEY

摘要:

The rate of coastal subsidence relative to southern Maine is found to increase linearly a total of 0.214 cm/yr from southern Maine to Hampton Roads, Virginia. The absolute rate of subsidence closely approximates the relative rate, since sea level at Portland, Maine, is rising at a rate close to the estimated value for the rate of the glacial‐eustatic rise. A marked discontinuity occurs in the vicinity of Cape Hatteras, south of which there appears to be no significant vertical land movement. The results are based on 23 yearly mean sea level series, each from 1939 through 197

ISSN:0148-0227    

DOI:10.1029/JC077i030p05930

年代:1972

数据来源: WILEY