bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radar echoes at vertical incidence from a horizontally stratified atmosphere
Authors: Browne I. C. 
Published: February 2007

AbstractAn exceptional radar echo of long duration which was observed from the zenith of an apparently clear sky is described, and it is shown that the height of origin of the echo was close to that of an anticylonic ‘inversion’ which was present at the time. It is deduced that the echo cannot have been due to a layer of water or dust haze at the inversion, but that it must have been caused by an abrupt discontinuity in the lapse rates of temperature, humidity, or both. If changes in humidity alone are taken into account, then in order to explain the observed intensity of the echo, it is necessary to suppose that the dew point changed by 15°F through a layer not more than 300 ft deep. It is suggested that more use might be made of radar for investigating such tropospheric discontinuities.
A quantitative analysis of the evolution of large‐scale flow with regard to the effect of eddy motion
Authors: Berson F. A. 
Published: February 2007

AbstractThe theory of pressure change by barotropic redistribution of absolute vorticity is extended to include the effect of an eddy motion represented by the departure of the daily value from a running five‐day mean. Application is made to a case in which the mean motion at the 500 mb level is featured by quasi‐stationary approximately zonal flow over North America and by slowly moving large vortices farther downstream (blocking situation of June‐July 1949). One result indicates the potentiality of a technique of forecasting the evolution of mean flow based on a persistence tendency of the ‘errors’ in barotropic tendency computations on mean charts. A further result concerns the interpretation of the ‘error’ field in the light of the neglected processes. There is, contrary to earlier results, no evidence of standing perturbations due to mountain ranges, but the horizontal eddy transfer of vorticity is shown to be an important factor. It is demonstrated that the latter transfer, viz., by the smaller eddies on approximately the cyclone‐wave scale, is mainly directed against the gradient of vorticity in the mean flow, thereby playing an essential role in the maintenance of the larger eddies. The transfer coefficient (diffusivity of relative geostrophic vorticity) is therefore predominantly negative, and its magnitude is from 109 cm2 sec−1 to 1010 cm2 sec−1. The action of the individual smaller eddies in transferring mean vorticity is evidenced by their paths in the relevant mean flow patterns.
Organization of kinetic energy realized in the atmosphere
Authors: McIntyre D. P. 
Published: February 2007

AbstractThe methods of Margules and Normand for investigation of the problem of storage and transformation of energy in the atmosphere are briefly described. Through discussion of an example of Margules it is shown that consideration must be given to the manner in which the kinetic energy, created in the process of energy transformation, is organized. In particular it is shown that dynamic factors severely limit the quantity of thermodynamic energy which can be released in the atmosphere.
A method for recording the formation and persistence of water deposits on plant shoots
Authors: Hirst J. M. 
Published: February 2007

AbstractApparatus has been designed to record the amount of water deposited on plant shoots by rain, dew and guttation, and how long the surfaces remain wet. These factors greatly influence the extent to which plants are infected by fungi causing such diseases as potato blight.The water on a cut potato shoot, sealed into a water‐filled chamber placed on a balance, can be weighed by recording, on a rotating drum, the changes in equilibrium of the beam. Deposits from rain appear rapidly; their persistence depends on the weather. In contrast, dew is deposited slowly over a long period and dries more rapidly. The heaviest dew deposit recorded was 6.9 × 10−3 g cm−2 compared with 9.6 × 10 g cm−2 for the amount of water retained during rain.
Secular changes in the rainfall regime of SE. Australia
Authors: Kraus E. B. 
Published: February 2007

AbstractAnalysis of long‐series rainfall records from Victoria and New South Wales shows a decrease of summer rainfall to a minimum about the turn of the century, and fifty years' gradual increase since then. Winter rainfall trends were opposite. Fluctuations of a much larger amplitude affected the rainfall regime of autumn and spring, suggesting possibly a discontinuous change of the climatic development about 1893.The winter rainfall of southern New South Wales is positively correlated with the mean strength of the westerlies at 300 mb. The correlation is negative in summer. It is concluded that the changes of the rainfall regime were associated with an increase of intensity of the upper westerlies to a maximum at about 1900 and a following decrease. During the period of maximum mean westerly flow the formation of east‐coast cyclones in autumn and spring may have been inhibited and the monsoon rains of tropical Queensland were below normal.
The coalescence between small water drops
Authors: Telford J. W. , Thorndike N. S. , Bowen E. G. 
Published: February 2007

AbstractAn experiment is described for measurement of the rate of coalescence in a cloud of droplets of nearly equal size. It is found that the value of the collection efficiency is unexpectedly high, and a physical explanation of the effect is given. The influence of electric charges on the droplets has been observed, and it is shown that increases by a factor of up to 20 in the collection efficiency are possible.
Some observations of turbulence near the sea bed in a tidal current
Authors: Bowden K. F. 
Published: February 2007

AbstractOceanographers are interested in turbulence in the flow of water in the sea or in estuaries because of its influence on the dynamics of water movements and mixing. These processes are more usually studied by their large‐scale effects, and detailed investigation of the turbulent fluctuations has been attempted less frequently in oceanography than on the model scale or in the atmosphere. This paper deals with fluctuations in the velocity components. Earlier observations were reviewed by Bowden and Proudman (1949), who also described experiments in the Mersey estuary, using the Doodson current meter. Further observations on similar lines were described by Bowden and Fairbairn (1952a). An attempt to measure the vertical fluctuations as well as the horizontal fluctuations was made by Francis, Stommel, Farmer and Parson (1953) in the Kennebec estuary, Maine.The observations described in this paper were made using an electromagnetic flow meter, a new type of instrument for this purpose. It was possible to measure the vertical component w, as well as the longitudinal component u, of the fluctuations, and hence the correlation between them. The instrument was designed at the National Institute of Oceanography, and uses alternating current at 50 c/s, passed through a coil, to produce the magnetic field. Two pairs of electrodes are used to measure the two components of flow in the plane perpendicular to the direction of the magnetic field. The measuring unit is only 4 in. in diameter and two such units can be mounted in various positions on a tripod, 6 ft high, which is laid on the sea bed. The potential difference across the electrodes is approximately 50 μv per kt, and is amplified by electronic circuits after induced p.d.'s, other than those due to the flow of water, have been balanced out. The output is recorded photographically.The observations at sea were made off Red Wharf Bay, Anglesey, in an area from 12 m to 20 m deep, where measurements of tidal currents and bottom friction had been made previously (Bowden and Fairbairn 1952b). The tidal currents at springs reach a velocity of about 2 kt at the surface. The technique employed was to lower the tripod from an anchored boat, a canvas fin keeping it orientated in the direction of the mean current while being lowered. The tripod with the measuring units remained stationary on the bottom while the records were taken and was raised again before the tidal current changed direction.
An experimental investigation of the 9.6 μ band of ozone in the solar spectrum
Authors: Walshaw C. D. , Goody R. M. 
Published: February 2007

AbstractMean heights of atmospheric ozone derived from two years' observations of the 9.6 p vibration‐rotation band are discussed. In each year there is a seasonal trend with a minimum mean height in summer and an annual range of 3.4 km. Careful consideration of sources of systematic errors shows that this result is probably due to changes in the ozone distribution, and a plausible seasonal cycle of changes of the ozone concentration in the troposphere and lower stratosphere is discussed. No other significant result is obtained and there is very little residual variance available for correlation with other meteorological phenomena.
The air flow over a ridge — the effects of the upper boundary and high‐level conditions
Authors: Corby G. A. , Sawyer J. S. 
Published: February 2007

AbstractThe solution obtained by perturbation theory for the airflow over a ridge depends on the mathematical conditions imposed at the upper boundary of the region for which a solution is obtained. New arguments are developed as to the choice of upper‐boundary condition appropriate to the atmospheric problem; these lead to the solution already adopted by Queney (1947).In certain airstreams it is possible for lee waves to have their largest amplitude in the upper troposphere and stratosphere. The character of the airstream at high levels plays a dominant part in determining the characteristics of these waves, but it has only negligible effects on the more familiar type of lee wave which has its largest amplitude in the lower troposphere.
Study of the SO2 oxidation in solution and its role in atmospheric chemistry
Authors: Junge Chr. E. , Ryan T. G. 
Published: February 2007

AbstractThe mechanism of SO2 oxidation in diluted catalytic solutions was studied. It was found that the oxidation stops after a certain pH value is reached. In the same catalytic solutions, the maximum possible SO4− formation is a linear function of the SO2 partial pressure in the air.This mechanism of SO4− formation can account for observed SO4− concentrations in rain, fog, and smog only if some neutralizing cations in the aerosols or traces of NH3 in the air are present. It is shown that in the latter case the system SO2NH3‐catalytic solution can explain the main features of SO4− formation in our atmosphere.
Radar echoes from atmospheric inhomogeneities
Authors: Jones R. F. 
Published: February 2007

AbstractThe possibility that radar echoes from atmospheric inhomogeneities are the explanation of echoes received in conditions which make it certain they are not received from precipitation elements (‘angel’ echoes) is examined quantitatively. It is shown that such an explanation is theoretically possible but that the required refractive index changes are large, involving changes of a few mb in vapour pressure and/or a few degrees C in temperature in a distance of about 25 cm. Reflection of the main or side‐lobe energy at a limited quasi‐horizontal surface is shown to give the most likely meteorological explanation, but the inability to measure changes of refractive index in the free atmosphere to the required accuracy prevents positive confirmation.
The reflection of short‐wave radiation by vegetation
Authors: Monteith J. L. 
Published: February 2007

AbstractThe fraction of short‐wave radiation reflected from agricultural crops was measured from May till September 1958 using two portable solarimetric thermopiles. Maximum reflection coefficients for grass, lucerne, potatoes, sugar beet, and spring wheat were between 0·25 and 0·27. Lower values found in the early stages of crop development, and for spring wheat even at maturity, can be correlated with low leaf areas and mutual shading of the leaves, also reduced reflection. Data by Billings and Morris (1951) have been used to compute total reflection coefficients for different types of vegetation including two desert species and to explain why these do not normally differ as much as the coefficients for the visible component.
Mean meridional distributions of ozone in different seasons calculated from umkehr observations and probable vertical transport mechanisms
Authors: Ramanathan K. R. , Kulkarni R. N. 
Published: February 2007

AbstractThe paper contains a study of the mean meridional distributions of ozone in different seasons. The vertical distributions of ozone at a number of stations at different latitudes in the Northern Hemisphere were worked out from the intensities of light scattered from the zenith sky on individual clear days using method B, i.e., the method of curve fitting, with suitable correction for secondary scattering. Diagrams of vertical distribution corresponding (1) to high ozone amounts (frequent in winter and spring) and (2) to low ozone amounts (frequent in summer and autumn) are shown. Mean distribution diagrams are also given for the months of March, July and November. An important feature of the distribution is the strong increase in ozone amount in March below 18 km when the latitude increases beyond 30°. The results are discussed in relation to the idea of a poleward flow of air from the lower stratosphere and the neighbourhood of the equatorial tropopause, as suggested by Dobson and Brewer from frost‐point measurements over the United Kingdom. The existence of a stratospheric warm air pool over the middle latitude in winter and spring as revealed by sounding‐balloon ascents is confirmatory evidence of this. The influence of the pool of cold air which exists in winter above 20 km in the stratosphere of the dark polar night is also considered. It is suggested that in winter and spring there is an ozone‐regenerating cycle due to meridional circulation in the stratosphere of tropical and middle latitudes, which carries air from the lower equatorial stratosphere to lower levels in the stratosphere of middle latitudes and puts back some of this accumulated air to higher levels in the equatorial stratosphere above 25 km. The more vigorous this circulation, the greater will be the rate of ozone storage in the lower stratosphere of extra‐tropical latitudes.
The fragmentation and electrification of freezing water drops
Authors: Mason B. J. , Maybank J. 
Published: February 2007

AbstractThe freezing of water drops is often accompanied by shattering of the ice shell and the production of small ice splinters. These phenomena have been studied in relation to the drop diameter in the range 30 μ to 1 mm, the nucleation temperature of the drop, the air content and purity of the water. The number of splinters produced is largely governed by the nucleation temperature (the degree of supercooling) which controls the quantity of air released during freezing and is not very dependent on drop size. Slightly supercooled drops of 1/10−1 mm diameter produced, on average, 20 to 50 splinters. The mechanism of drop fragmentation is discussed and the potential importance of splintering in the ice‐nucleus economy of clouds is assessed.Fragmentation of freezing drops is accompanied by electrical charging, usually with the splinters positively charged and the drop residue carrying a negative charge. The magnitude of the residual charge which, on average, is observed to be about 10−3 e.s.u. for a millimetre drop, is related to the same factors which control splinter production. Charging by this mechanism would not appear to be of major importance in the electrification of thunderstorms.
Winds in the upper atmosphere
Authors: Greenhow J. S. , Neufeld E. L. 
Published: February 2007

AbstractA systematic study of the winds in the upper atmosphere has been carried out during the 5‐yr period 1953 to 1958. At heights of 85 to 100 km regular prevailing and periodic tidal wind components have been resolved. Components of the prevailing wind of about 20 m sec–1 towards east are observed during the summer and winter months, with similar westward components during spring and weak westward winds in autumn. Large southward components of approximately 20 m sec–1 are observed during the summer. The amplitude of the semi‐diurnal periodic wind is also about 20 m sec–1, and this component can usually be represented by a vector which rotates in a clockwise direction with constant amplitude twice every 24 hours. Large departures from this simple model occur at certain times of the year. Measurements of the 24‐hr and 8‐hr periodic wind systems are also described, and an upper limit of 2 m sec–1 is determined for the lunar semi‐diurnal wind component.
Cloud‐droplet growth by condensation in cumulus
Authors: Mason B. J. , Chien C. W. 
Published: February 2007

AbstractThe growth of droplets by condensation upon a spectrum of salt nuclei is followed as they are carried up in a small cumulus which mixes and exchanges heat, momentum and water vapour with its surroundings. The vertical velocity, water content, supersaturation and cumulative drop‐size distributions are plotted as functions of time and height above cloud base. Growing cloud droplets are continually being transferred from the cloud to the drier environment and replaced by new condensation nuclei. The fact that some droplets remain in the cloud longer than others is largely responsible for the evolution of a broad drop‐size distribution which much more closely resembles observed spectra than those obtained from previous calculations for a closed parcel. Regarding the formation of large droplets, the calculations show that droplets exceeding 20 μ in radius arise on salt nuclei of mass 10−10 g and droplets larger than 30 μ radius arise on nuclei of 10−9 g within ten minutes of the air passing through the condensation level. Continued growth in a succeeding thermal and further deformation of the droplet spectrum by coalescence will produce even larger drops, but nevertheless it is difficult to explain the appearance of droplets larger than 30 μ in concentrations of order 1 cm−3 in terms of their growth on reported concentrations of giant hygroscopic nuclei.
Infra‐red absorption, scattering, and total attenuation cross‐sections for water spheres
Authors: Herman B. M. 
Published: February 2007

AbstractCalculations of the normalized absorption, scattering, and total attenuation cross‐sections of water spheres are presented for the wavelength range from 4 μ to 24 μ, at intervals of 1 μ for the wavelength interval from 4 μ to 10 μ, and at 2 μ intervals thereon to 24 μ. The calculations have been carried out to values of α (α is the ratio of sphere circumference to wavelength) of 30. For values of the Mie absorption parameter, k, greater than approximately 0·10, values of the normalized absorption cross‐section are shown to have a maximum which exceeds unity by an appreciable amount. In all instances, the values of the normalized scattering and total attenuation cross‐sections exceed unity over most ranges of α considered, the excess over unity being greater for small values of absorption. Some rough calculations are made comparing Mie absorption coefficients with those for bulk‐water absorption at the same wavelength.
The representation and analysis of vertical distributions of ozone
Authors: Godson W. L. 
Published: February 2007

AbstractA new diagram is proposed for the representation and analysis of the vertical distribution of ozone – the ozonagram with basic coordinates of ozone partial pressure and the logarithm of total pressure. It is shown that only this diagram satisfies a set of seven criteria devised to meet all dynamical, analytical and graphical requirements. Convenient symbols and units are also proposed for various ozone parameters.The ozonagram is applied to the representation and analysis of umkehr data for the Canadian stations of Moosonee and Edmonton (Mateer and Godson 1960). The basic features of the seasonal variations are illustrated, in particular, the relative roles of the lower and middle stratosphere, the latter being largely responsible for the annual ozone maximum. The effects of changes in air mass are investigated for several seasons, but no unique pattern emerges. Even when middle‐stratosphere temperatures do not change significantly, it appears that middle‐stratosphere ozone concentrations do change, in a variable manner. In the absence of dynamic activity in the middle stratosphere, however, the Normand‐Reed mechanism can be substantiated.
The description of rain by means of sequential raindrop‐size distributions
Authors: Dingle A. N. , Hardy K. R. 
Published: February 2007

AbstractThe photoelectric raindrop‐size spectrometer has made possible the resolution of drop‐size spectra in natural rains to 1‐min intervals of time. Characteristics of the drop‐size spectra thus obtained and their time‐sequences are discussed. Various factors affecting the development of raindrop‐size distributions are discussed as they relate to the observed distributions.Qualitatively it is indicated that the outstanding observed characteristics of the drop‐size distributions for moderate‐ to high‐intensity rains are primarily attributable to wind‐shear and gravity sorting at the onset of rain and to aerodynamic break‐up and impact splashing of drops, and that predominance of the coalescence or of the Bergeron‐Findeisen process of raindrop formation may be indicated by features of the ground‐level drop‐size distributions.
Aircraft observations near jet streams
Authors: Briggs J. , Roach W. T. 
Published: February 2007

AbstractThe results of an analysis of 22 flights through jet streams by aircraft of the Meteorological Research Flight are presented. The average distributions of wind speed, vertical and horizontal wind shear, potential temperature, water vapour, cirrus cloud and ozone are obtained in relation to the jet core, and are discussed in relation to existing literature on jet streams.A particular feature observed on a few flights was the apparent protrusion of a tongue of stratospheric air contained within well‐marked frontal boundaries into the baroclinic zone found below and on the low‐pressure side of the jet core. Occurrences of high‐level turbulence are related to various parameters, and the primary importance of vertical wind shear indicated. It is suggested that clear‐air turbulence may play a major role in the erosion and eventual disruption of this upper frontal zone.
The electrification of freezing water droplets and of colliding ice particles
Authors: Evans D. G. , Hutchinson W. C. A. 
Published: February 2007

AbstractWhen supercooled drops of diameter 1·3 mm were nucleated at — 0·2$C and froze in an environment at — 15$C and fragmented, the average charge on positive residues was 1·5 × 10−3 e.s.u., and on negative residues — 2·2 × 10−3 e.s.u. The charges were comparable with those found in similar measurements by Mason and Maybank but were usually far too large to be accounted for by the Latham‐Mason temperature‐gradient theory.When ice crystals differing in temperature by up to 10$C were brought into momentary contact, any charge produced was less than 10−4 e.s.u. This result is not inconsistent with the Latham‐Mason theory and does not confirm the much larger values reported by Reynolds et al.
Experimental determination of collection efficiencies for small water droplets in air
Authors: Woods J. D. , Mason B. J. 
Published: February 2007

AbstractThis paper describes measurements of collection efficiencies for gravitational collisions between water drops of radius R = 30 to 55 μ and saline droplets of radius r = 1 to 12 μ. the results agree quite well with those obtained earlier by Picknett for drops of R = 30, 40 μ and also with the collision efficiencies computed by Hocking, Mason and Shafrir and Neiburger except that, for values of r/R < 0·1, the experimental values are consistently higher than the calculated values and fail to show the sharp cut‐off predicted by theory. the experiments support Hocking's prediction that drops of R ⩽ 18 μ will fail to collect droplets of smaller size.