bluuebunny/crossref_metadata_2025_split huggingface dataset:
The composition of coagulation‐elements in cumulonimbus
Authors: Ludlam F. H. 
Published: February 2007

AbstractCalculations are made from which it appears that the rate of loss of heat from ice particles growing by coagulation in dense supercooled clouds may be insufficient to allow all the acquired water to freeze. The larger coagulation‐elements within cumulonimbus clouds may therefore have liquid skins at levels where the temperature has fallen to −20° or −30°C. The rain‐drop multiplication process envisaged by Langmuir may thus proceed also at temperatures well below 0°C, and the effect may also be important in the production of ice nuclei by‘splinter’ formation and in the generation of thunderstorm electricity.
On the theory of large‐scale vortex motion in the atmosphere
Authors: James R. W. 
Published: February 2007

AbstractA consideration of the parameters best suited to characterising a circular vortex leads to the conclusion that an intensity factor, the central pressure defect (or excess) and a scale, or size factor are fundamental.General expressions are given for the mass defect of a cyclone, its total potential energy, and the total kinetic energy of geostrophic winds. These parameters are estimated for 17 cyclones on the basis of an assumed pressure‐profile shape. It is shown that the ratio of the mean geostrophic kinetic energy to the mean potential energy is of the order 0.08.A dimensionless measure of the‘flexure’ or bending of a pressure profile is shown to vary relatively slightly from cyclone to cyclone, suggesting that the profile shape is roughly the same for all symmetrical lows.The kinetic energy arising from ageostrophic components of wind are also discussed and it is shown that a quasi‐geostrophic vortex in bodily movement has the same (ageostrophic) kinetic energy as a rigid body moving with the same speed and having a specified mass, the virtual mass of the vortex. It is shown that the virtual mass of a cyclone is of the same order as the total mass defect.It is shown how elleptical vortices, troughs and wedges may be treated, and a‘front’ is shown formally to be representable as a line distribution of circular vortices.On the basis of the models introduced, a dynamic theory of quasi‐geostrophic vortex interaction is put forward, based on the hypothesis that in mutual interaction the pressure profiles of individual vortices are conserved.This theory leads to the conception of a potential barrier inhibiting the over‐close approach of two vortices, and permits vortex interaction to be conceived as the motion of attracting and repelling'centres of action.
The meridional eddy flux of energy
Authors: White Robert M. 
Published: February 2007

AbstractAn investigation of a large number of upper‐air soundings over regions of North America shows that the eddy transport of sensible heat is poleward in the mid‐latitude troposphere, reversing and becoming equatorward in the stratosphere. The eddy transport of sensible heat reaches its maximum in middle latitudes, decreasing both poleward and equatorward. It is shown wherein these results differ from those recently presented by Priestley. The transport of sensible heat has a high seasonal variation, being much stronger in winter than in summer. There are indications that at very low latitudes the eddy sensible‐heat transport is directed equatorward.The eddy transport of latent energy is described by means of the same soundings and is found to be poleward throughout middle and high latitudes with a maximum at the ground and decreasing with altitude. The principal seasonal variation in the transport of latent energy appears to be the northward shift of the mid‐latitude maximum from winter to summer. This maximum is not very pronounced, the transport in both seasons being relatively constant through middle latitudes.
A hemispherical study of the atmospheric angular‐momentum balance
Authors: Starr V. P. , White R. M. 
Published: February 2007

AbstractAn attempt is made to determine the meridional eddy transport of angular momentum for the northern hemisphere in the vicinity of 30°N. latitude from upper‐wind observations for a period of six months. Two somewhat different methods of evaluation give essentially comparable results and indicate the presence of eddy transports which are ample to compensate for frictional losses of angular momentum farther north. No indications of the presence of a mean meridional circulation of the strength and character needed to produce a sensible northward transport of angular momentum are found.
Seasonal variation of the axes of low‐latitude pressure and divergence patterns over the oceans
Authors: Gordon A. H. 
Published: February 2007

AbstractThe seasonal fluctuations of the mean latitudes of the axes of the doldrums and sub‐tropical anticyclones over all the oceans, and of the belts of maximum convergence and divergence of surface winds over the North Atlantic are evaluated and discussed. There is a lag of about two months after the sun is vertically overhead in the positions of the axes. The seasonal movement of the axes of the sub‐tropical anticyclones is about half that of the axes of the other elements considered. In the North Atlantic and West Pacific Oceans the correlation between the mean latitudes of the axes of the doldrums and sub‐tropical anticyclones is high.
The dissipation of kinetic energy in the lowest layers of the atmosphere
Authors: Taylor R. J. 
Published: February 2007

AbstractThe supply of kinetic energy to a shallow layer of air is considered. The cases chosen for analysis comprise occasions of comparatively strong wind and of fairly small temperature gradient so that the supply of kinetic energy from the vertical flux of total heat is not important at small heights. In these cases the diffusive flux of kinetic energy is also shown to be negligible. Hence it follows that, on these occasions, the rate of dissipation per unit volume is given by the product of the local values of the shearing stress and vertical gradient of mean velocity when steadiness and horizontal uniformity of the turbulence are assumed. Estimates of the rate of dissipation per unit mass at heights from 1 m to 50 m are made for particular occasions and used, together with the observed energy densities, to provide estimates of the size of the dissipating eddies at the heights of observation according to expressions given by L. F. Richardson and G. I. Taylor.
The wind stress over the ocean from observations in the trades
Authors: Sheppard P. A. , Omar M. H. 
Published: February 2007

AbstractThe method of geostrophic departure is used to determine the surface drag of the ocean in the Trade‐wind belt, this region being particularly suitable for the technique because the opposition of the thermal wind to the surface geostrophic wind leads to a maximum in wind speed at a few hundred metres elevation. This pilot study is based on balloon winds at three very small Pacific islands and the U.S.W.B. Northern Hemisphere Charts of surface pressure. A drag coefficient of 1·0 × 10−3 is found from two of the stations, and 1·5 × 10−3 at the third and there is no systematic variation with surface‐wind speed from 3 m/sec to 12 m/sec. The higher value of drag coefficient may be due to excessive roughness caused by reefs, or possibly to thermal instability.A similar analysis for San Juan in the West Indies shows the disturbing effect of a larger land area on the geostrophic departure so that only in high surface winds does the apparent drag tend to the probable value. Some other features of the Trade‐wind regime are briefly described.
Some downstream effects associated with large‐amplitude troughs in upper flow patterns
Authors: Smith C. V. , Forsdyke A. G. 
Published: February 2007

AbstractThe change in amplitude of troughs occurring downstream of a (primary) trough in the 500‐mb contour pattern over America, is examined for the four days subsequent to the first formation of the American feature.Over the time interval considered, the association between a large‐amplitude primary and the presence, in a broad sector to the east, of a large‐amplitude downstream trough is found, in general, to be small. The association increases markedly however when a primary persists for two or three days : on a large proportion of such occasions the next downstream trough attains dimensions comparable with that of the primary. Persistence of this downstream trough would frequently appear to be directly related to persistence of the upwind (primary) trough.
The length of dry and wet periods
Authors: Longley R. W. 
Published: February 2007

AbstractA study was made of the length of dry and wet spells at five Canadian cities. From the results of the study it was learned that after a wet day the probability of the following day being wet is constant no matter how long the wet period has persisted; the same is true for the weather following a dry day except that there is a slight increase in the probability of dry weather with increasing length of the dry period.As a corollary to the study, the probability of the weather following either a wet or dry day was determined for each month for each of the five cities. Also a simpler method is suggested for determining approximations to these figures.
Spectral line shape and its effect on atmospheric transmissions
Authors: Curtis A. R. , Goody R. M. 
Published: February 2007

AbstractThe detailed shape of a pressure‐broadened spectral line obtained by Lindholm has been evaluated and used to derive an expression for the mean transmission of a disordered band. This is compared with the corresponding expression using the Lorentz line shape. It is shown that the difference in mean transmission for these two line shapes is scarcely detectable spectrophotometrically in the cases of the principal telluric bands of ozone and water vapour, and probably also for carbon dioxide. It is concluded that, until more important problems have been solved, it is probably uneconomical to make use of line shapes any more complicated than that of Lorentz for computations of heating rates in the atmosphere, provided always that theory is used only in order to apply existing laboratory data to atmospheric conditions.
The partition and intensity of eddy energy at the 91‐metre level during unstable conditions as observed at Brookhaven National Laboratory
Authors: McCormick Robert A. 
Published: February 2007

AbstractThe magnitude and partition of eddy energy is reported for a series of observations near 91 m in which the period of averaging varied from 10 sec to 57 min. Of the 15 observations studied, 14 were made during unstable conditions typical of the predominant daytime regime found at Brookhaven in the lower 125 m. By means of moving averages as frequency filters, theree sections of the eddy‐energy spectrum are investigated. It was found that (a) the magnitude of the turbulent energy is proportional to the rate of energy supplied by the Reynolds's stresses and buoyancy forces, (b) the partition of eddy energy becomes increasingly unequal with increasing eddy size, and (c) two turbulence regimes apparently exist at 91 m with characteristics which depend on the trajectory of the air.
Short‐period variations in surface pressure and wind
Authors: Pothecary I. J. W. 
Published: February 2007

AbstractPeriodic variations in surface pressure and wind velocity recorded by autographic instruments on 5 July 1952 are related to wave motion along a horizontal temperature discontinuity. The wave motion is considered to have been set up when the outflow of cold air from an intense outbreak of thunderstorms over the western English Channel temporarily blocked the north‐easterly airstream beneath an inversion over southern England and the Midlands.The oscillation was propagated upstream of the lower current and across the upper south‐easterly current for over 250 mi, with an amplitude approaching 200 m in the earlier stage.
The drag of spherical rubber balloons
Authors: Mapleson W. W. 
Published: February 2007

AbstractAn empirical relation Cd = 2.7 × 105 R−1 is given between drag coefficient, Ca, and Reynolds number R, for a captive, nominally spherical, rubber balloon, for the range log10 R = 5.1 to 5.8. It is suggested that the drag increases as the shape of the balloon progressively deviates from the spherical. A calibration of a Meteorological Office radiosonde windmill as a cup anemometer is also included.
Climate, host and parasite in crop disease
Authors: Grainger John 
Published: February 2007

AbstractThe effects of climate on both host and parasite have been studied for two serious crop diseases of west Scotland.First‐early Epicure potato crops in the coastal belt of Ayrshire and Wigtownshire make appreciable tuber growth before the soil temperature rises to 43°F, which is the minimum temperature of activity of the potato‐root eelworm, Heterodera rostochiensis. By the time the earliest crop is lifted early in June, cysts of the eelworm are white or yellow in colour. It is shown that such cysts make little contribution to the permanent soil infestation, thus explaining the low infestations of land consistently devoted to the growth of first‐early crops. Later lifting allows the cysts to become brown, and such cysts add considerably to the permanent soil infestation. The initial period of eelworm‐free growth on first‐earlies limits the loss in yield to 30 to 40 per cent, as compared with 80 to 100 per cent loss if the variety Epicure were planted later, at the time for a maincrop variety.Correlation coefficients have been calculated for comparisons over eight years between the percentage of club‐root disease on swede turnips and monthly means of air and soil temperatures, bright sunshine and rainfall, for the separate months from May to October. Significant and near‐significant correlations show that a low incidence of the disease is associated with a relatively high soil temperature in July, relatively high amounts of bright sunshine in June, July and September, relatively low rainfall in September and relatively high rainfall in October.The differential effect of soil temperature on host and parasite with potato‐root eelworm is a ‘disease‐escape’ mechanism but the effects of bright sunshine on the amount of club‐root disease are considered to be, in the present setting, an effect upon disease involving growth of the host.
Two‐way relationship between the snow or ice limit and 1,000–500 mb thicknesses in the overlying atmosphere
Authors: Lamb H. H. 
Published: February 2007

AbstractStatistical studies of 1,000–500 mb thickness, (i) occurring with frozen or unfrozen forms of precipitation and (ii) prevailing at various distances from the snow or ice limit over wide regions with snow or ice cover, over bare ground and over open sea are used to discover (a) the likelihood that precipitation will take the form of rain or snow in given circumstances and (b) the behaviour of the thickness when well‐established and extensive snow or ice fields are encountered. The results indicate an important influence produced by snow fields of the order of 1,000 mi and more in longitudinal extent upon the general circulation of the atmosphere.Choice of 1,000–500 mb thickness as an indicator rests upon its adequacy and upon its general use and availability in forecasting offices; some preliminary argument is devoted to showing that the choice is reasonable on these grounds and that the lack of refinement involved in considering thicknesses of so deep a layer is not serious.
The effects of a large island upon the trade‐wind air stream
Authors: Malkus Joanne S. 
Published: February 2007

AbstractA series of four helical aircraft soundings across the island of Puerto Rico on a sea‐breeze day are analyzed and interpreted. The existence of a fairly symmetrical orographic‐convection cell with ascent over the island and compensating subsidence in a surrounding ring is established. The field of motion in the convection cell is deduced from the observations together with the theoretical work on flow over heated islands by Malkus and Stern (1953). The plausibility of the motion field is tested by construction of a moisture budget for part of the cross‐section delineated by the soundings, and the effects of the subsidence, lifting, heating and other processes imposed upon the air stream by its passage over the island are discussed, with particular emphasis upon alterations in the upward transport of water vapour and cumulus cloud structure.
The representation of the annual temperature variation over central and northern Europe by a two‐term harmonic form
Authors: Craddock J. M. 
Published: February 2007

AbstractA harmonic analysis is made of the annual temperature variation at 42 stations spread over central and northern Europe, using in each case 5‐day mean temperatures averaged over a considerable number of years. It is found that the first two harmonics account for nearly all the annual variance, the residual variance being usually less than 0.4 per cent of the total. Most of this residual variance seems to be random in origin, but a small part may be due to systematic departures from the two‐term harmonic form.
Water losses from various land surfaces
Authors: Rider N. E. 
Published: February 2007

AbstractAn account is given of observations designed to evaluate the daily water losses from surfaces carrying crops of different size and shape which were transpiring at their potential rates. The losses were obtained by the familiar aerodynamic method, the observations being made over bare soil, brussels sprouts, peas and grass. It is shown that the differences in the water losses from the various surfaces are too large to be accounted for by likely errors in the observations or method. Typical losses for sunny days in the period May to July 1955 were: peas, 2.5 to 7.5 mm; grass, 2 to 3 mm; brussels sprouts about 4 mm.
The vertical distribution of aphids in the air and the temperature lapse rate
Authors: Johnson C. G. 
Published: February 2007

AbstractAphid density diminishes with height above the ground; the linear regression coefficient, ‐b, of log density on log height is an approximate expression of the vertical density profile. A low negative value of b suggests a relatively high degree of upward transport, and a high value the reverse.From May to October 1948, aphid densities were estimated simultaneously at 6 heights from 50 to 2,000 ft over 2‐hr periods during the day: lapse rates to 2,000 ft were also measured. The regression coefficient, ‐b, of log density on log height was inversely correlated with the mean lapse rate between months; September and October were associated with low lapse rates and steep density gradients.Correlation coefficients of b with lapse for 2‐hr periods were negative above a lapse of 10°F/2,000 ft, and became statistically significant in the afternoon. Below the 10° value no significant correlation existed, probably because low lapse rates occurred usually in the early morning when densities were low and factors other than atmospheric mixing could affect the profile.Two examples of the change in the vertical profile from hour to hour throughout the day are given to illustrate the association of high lapse rates with high‐altitude dispersal and the limitation of upward transport when lapses are low: but biological factors also play a part in determining the form of the profile and these are briefly discussed.
The detection and measurement of water droplets
Authors: Liddell H. F. , Wootten N. W. 
Published: February 2007

AbstractThe use of a dyestuff (Naphthol Green B) in gelatine, coated on the slides of a cascade impactor, provides a method for determining the drop‐size distribution of fogs and water sprays which is easy to apply in practice and gives a permanent record for subsequent microscopic analysis. Calibration of the stain remaining after evaporation of a droplet impacting on the slide shows it to be, on the average, 2.5 times the diameter of the droplet. The method can be readily used for droplets of less than 1 μ diameter.
Integrated absorbtion by the 9.6 μ band of ozone
Authors: Walshaw C. D. 
Published: February 2007

AbstractAn account is given of laboratory measurements of absorption by the 9.6 μ band of ozone using dry air as the foreign gas. The experimental results for the band area, Ar, are tabulated for ozone amounts up to 1.5 cm STP and pressures from 10 to 760 mm Hg at a temperature of 20°C; the slit width is 6.5 cm−1. An empirical formula for Ar is given. The best fit is obtained with slightly modified values of the ultra‐violet absorption coefficients determined by Vigroux (1953), when the standard error in band area is 2.4 per cent.
Aircraft observations of rain and drizzle from layer clouds
Authors: Singleton F. 
Published: February 2007

AbstractAircraft observations of droplets greater than 100 μ diameter in 20 low layer clouds indicate that these drops can occur in concentrations of approximately 0·1 per litre to 10 per litre in clouds of 1,000 ft (300 m) to 7,000 ft (2,100 m) thickness. These observations are presented together with data relating the thickness and height of a further 120 layers of low cloud to their ability to produce precipitation at the ground. A diagram is shown which, it is suggested, might be of use as an objective aid for forecasting the occurrence of precipitation from low‐layer cloud.The results are discussed qualitatively in terms of the condensation‐coalescence mechanism of droplet growth and demonstrate the efficiency of layer clouds as producers of large drops (and consequently precipitation). There is evidence that, for the range of cloud depths considered, coalescence is the predominant mechanism for drop growth for temperatures down to – 11°C to – 12°C.
The compensation of the effects of potential‐gradient variations in the measurement of the atmospheric air‐earth current
Authors: Adamson J. , Chalmers J. A. 
Published: February 2007

AbstractA well‐known method of determining the atmospheric air‐earth current consists of collecting and measuring the current flowing into an insulated receiver at ground level. A difficulty encountered, however, is that any variation of the potential gradient produces a displacement of the bound charge on the collector, leading to a spurious ‘displacement’ current. In the simplest form of the method, this current can occasionally be so large as to mask completely the true‐earth current.This article describes a development in which the sum of the air‐earth and displacement currents is measured at one terminal of a differential amplifier, while a field machine provides automatic and continuous compensation for the displacement current at the other terminal. The apparatus thus enables a continuous true recording of the air‐earth current to be made, and is an improvement on previous methods of eliminating the displacement current which necessitated intermittent recording of the integrated charge collected over a period of time. Satisfactory results are obtained with this method in all weather conditions except thunderstorms.
Some observations of drop‐size distributions in low layer clouds
Authors: Singleton F. , Smith D. J. 
Published: February 2007

Abstract125 drop samples in ten layers of low cloud of thickness 700‐7,500 ft (210‐2,300 m) have been obtained using the magnesium‐oxide coated‐slide technique. These observations are discussed in terms of the condensation‐coalescence mechanism. Comparison has been made between these observations and a similar set, also obtained by the Meteorological Research Flight, Durbin (1959), for convective cloud, from which it is shown that the coalescence process is in greater evidence in the layer clouds. Values of water content deduced from the drop spectra are higher than those previously reported by other workers and correspond in magnitude to the full adiabatic values suitably modified by redistribution within the cloud.Some measurements are also discussed relating to the effect of the aircraft on the representativeness of the drop samples. The extension of the magnesium‐oxide calibration to drops larger than 100 μ diameter has also been examined experimentally.