bluuebunny/crossref_metadata_2025_split huggingface dataset:
The identification of weather conditions associated with the generation of major storm surges along the west coast of the British Isles
Authors: Sutcliffe R. C. , Lennon G. W. , Sutcliffe R. C. , Sutcliffe R. C. 
Published: February 2007

AbstractThe complex mechanism of storm surge generation in the Eastern Atlantic has introduced severe difficulties in attempts to establish the basis of a flood‐warning system for the west coast of the British Isles. As an interim measure, while coastal defences are being assessed in the light of the estimated probability of abnormal levels (Lennon 1963) and while research proceeds so that any consequent contingency may eventually be met, a qualitative technique has been devised which aims at an identification of weather situations which are potentially dangerous particularly for the British Channel area and for Liverpool Bay.Major surges are found to be generated as a result of the passage, over the sea approaches to the region, of a certain type of depression which, moving at a critical speed over shallow water, can establish conditions of near‐resonance. The relevant meteorological conditions are found to be remarkably uniform and capable of definition.
Unattended long‐period evaporation recorder
Authors: Summer C. J. , Swinbank W. C. 
Published: February 2007

AbstractAn evaporimeter installation is described consisting of a battery‐operated long‐period recorder coupled to a supply water tank and raingauge. The supply tank is connected to a standard evaporimeter through an automatic control valve, which regulates the supply of water to replace that lost by evaporation, and disposes of excess water due to precipitation, so that evaporation in all weather conditions can be recorded. The equipment is capable of operating for periods up to 6 months unattended, the recorder having an accuracy within ± 0·01 in. water level.
Production of droplets and salt nuclei by the bursting of air‐bubble films
Authors: Day J. A. 
Published: February 2007

AbstractAir bubbles which burst at the surface of a liquid give rise to an array of small bubble‐film droplets and subsequent jet drops. Both are of meteorological significance in that they are the major means by which salt particles are injected into the atmosphere.Counts are made of the numbers of film droplets produced by bubbles of known diameter as they burst in the highly supersaturated environment of a water diffusion cloud chamber.It is found that, (1) the number of film droplets produced is dependent on bubble size, ranging from none for 0·1 mm diameter bubbles to 300–400 for 4 mm diameter bubbles in salt water; (2) the mean number of film droplets is proportional to the one‐half power of the bubble cap area; (3) larger numbers of film droplets are produced when bubbles burst in three per cent NaCl solution than in filtered sea water, and significantly larger numbers are produced in saline than in distilled water; (4) for a particular diameter of bubble, the film‐droplet count for successive ruptures assumes a Gaussian distribution in which one standard deviation is about one‐third of the mean number.
A study of raindrop‐size distributions in the free atmosphere
Authors: Caton P. G. F. 
Published: February 2007

AbstractObservations of frontal precipitation using a vertically‐looking 3.2 cm pulsed Doppler radar have been analysed to indicate the raindrop‐size distributions present below the melting band. The variations of size distribution with rainfall rate and with height are discussed. The distributions at 750 m above ground show both fewer small drops and fewer large drops than the corresponding Marshall and Palmer (1948) exponential distributions. At greater heights there are more small drops but even fewer large drops. The changes of rain‐flux and drop‐size distribution with height provide evidence in support of raindrop coalescence but, in general, indicate the absence of pronounced accretion or evaporation. Experimental relations between equivalent reflectivity factor Ze and rainfall rate R have been derived for two heights; extrapolated to ground level the relation is Ze = 285 R1.30 for continuous frontal rains of 0.1 to 5.0 mm hr−1 at Pershore. Instances of vertical air motion due to waves induced by hills have been diagnosed.
The growth of cloud droplets by coalescence
Authors: Bartlett J. T. 
Published: February 2007

AbstractA simple model of a cloud in which drops of different sizes are assumed to be falling at their terminal velocities is used to study the development of drops with radii up to 40 μ by the coalescence mechanism.It is not clear what initial distributions of drop sizes should be used in this study and therefore the development of larger drops from several different distributions which are thought to be characteristic of the early stages of various types of cumuli are compared. In this part of the paper Hocking's (1959) values of the collection efficiencies are assumed to apply. It is found that large drops develop rapidly in maritime clouds, and for clouds characteristic of continental climates it is shown that the maximum drop radius needs to be greater than about 22μ for the coalescence mechanism to be effective. There must also be an adequate supply of drops with radii between 14 and 20 μ.The effects of small increases in the collection efficiencies which may be caused by various factors, such as turbulence or electric fields, are studied with the model using two different initial drop size distributions. It is found that the most important single parameter in determining the onset of the coalescence mechanism is the minimum drop size capable of capturing still smaller drops. Generally, a significant effect is found if the change in the collection efficiency is equivalent to increasing the radii of the interacting drops by more than about 2μ. It is suggested that any future computations or experiments to determine changes in the collection efficiencies should look for effects of this magnitude.
Some determinations of atmospheric absorption by measurement of solar radiation from aircraft and at the surface
Authors: Robinson G. D. 
Published: February 2007

AbstractMeasurements, on aircraft and at the ground, of the downward and upward fluxes of solar radiation and illumination in cloudless conditions are compared with computed values and with each other. The indirect estimates of absorption from surface observations are in agreement with the more direct aircraft measurements. As in previous work, measured absorption and upward scatter is considerably in excess of that computed ‐ excess by about a factor of two at heights up to 20,000 ft. The discrepancy is attributed to suspended matter.
Eddy fluxes and the biennial stratospheric oscillation
Authors: Wallace J. M. , Newell R. E. 
Published: February 2007

AbstractThe zonal wind together with the eddy transports of momentum and heat at low and middle latitudes in the stratosphere of the Northern Hemisphere are found to display a two year periodicity which results from a sequence of alternating weak and strong winters, where ‘weak’ and ‘strong’ refer to the intensity of the eddy circulations at middle latitudes. At levels above 30 mb, the modulations in the eddy momentum transports appear to be strong enough to account for the year to year changes in westerly momentum in the tropics.Similarities between the stratospheric oscillation and the biennial pulse in tropospheric data suggest an interrelation between the two phenomena. The two year periodicity may not be a permanent feature of the general circulation.
A difficulty in the interpretation of certain solar radiation measurements
Authors: Hamilton R. A. , Collingbourne R. H. 
Published: February 2007

AbstractMeasurements of global and diffuse radiation were made at Lerwick on a number of cloudless summer days, most of them in a very clear atmosphere. Even on the clear days about 10 per cent of the global radiation appears to be absorbed, in addition to that predicted for a model atmosphere and the amount of scattered radiation is about twice the computed Rayleigh scattering. Whereas extra scattering increases with air mass as expected, the apparent absorption decreases with increasing air mass. No physical explanation of this absorption anomaly is apparent, and no reasonable adjustment to the assumed coefficients of scattering and absorption removes it. It would be removed if the sensitivity of the Kipp solarimeter were assumed to vary with the angle or intensity of the incident radiation by as much as 10 per cent over the range concerned but special tests, carried out on Kipp solarimeters at Kew, do not provide evidence to support this assumption.
On the nature of the summit areas of severe storms in Oklahoma
Authors: Roach W. T. 
Published: February 2007

AbstractPhotographic and radiometric records of the summit areas of severe storms in Oklahoma obtained from a U‐2 aircraft flying at an altitude of 65,000 ft (20 Km) are combined with relevant synoptic data to make some tentative deductions on the nature of the flow and temperature fields in the outflow regions of the small fraction of giant storm cells which appear to have attained some form of quasi‐steady state.The summit area of a giant cell sometimes appears to consist of a rather smooth ‘gasometer‐shaped’ dome 5–8 nautical miles (10–15 Km) in diameter and reaching up to 20,000 ft (6 Km) above its environmental tropopause. It is suggested this dome consists mainly of air which has risen nearly adiabatically from the surface layers (after Ludlam 1963) contained within a rather thin shell of very stable air in which there is mixing between updraught air and environmental (stratospheric) air.A general description of the distribution and heights of storm tops along a developed squall‐line is also given.
Effect of vertical wind shear on the growth of convective clouds
Authors: Rao N. S. Bhaskara , Dekate M. V. 
Published: February 2007

AbstractThe relationship between vertical wind shear and the vertical extent of convective clouds is examined. In order to take into consideration the movement of the cloud, a ‘Relative Top Shear’ (RTS) is defined. Radar data and upper winds at some Indian stations in different seasons have been studied and a comparison made between RTS at different levels and the maximum tops of convective clouds. The results show that deep convective cloud was confined to layers in which RTS did not exceed 10 kt/km.
Further work with the Bushby‐Timpson 10‐level model
Authors: Benwell G. R. R. , Timpson Margaret S. 
Published: February 2007

AbstractVertical smoothing of the initial height fields proved to be a crucial step in obtaining 24 hr forecasts using the 10‐level primitive equation model (Bushby and Timpson 1967) on any set of data : the particular operator used and the effects on the forecast fields are described. The latent heat effect is examined quantitatively by comparing two 24 hr forecasts, one of which included and the other excluded the contribution of the latent heat of condensation. The forecast fields obtained when a larger grid length is used, in conjunction with an appropriately lengthened time‐step, are compared with forecasts obtained from the basic grid length and time‐step and the implications arising from the increase of scale are discussed.
The exchange of momentum, mass, and heat between an artificial leaf and the airflow in a wind‐tunnel
Authors: Thom A. S. 
Published: February 2007

AbstractInvestigation of a proposed relationship between the skin friction part of the drag on a natural surface and a simultaneous transfer of mass or (sensible) heat led to measurements of the dimensionless transfer coefficients Cd, Cv and Ch for the exchange of (stream‐wise) momentum, mass, and heat, between a single artificial leaf and the airflow in a wind‐tunnel. It was shown that Cv, h = C0(D/v, k/v)2/3 where D, k and v are the molecular diffusivities in air of gas or vapour, heat, and momentum, and where C0 is a generalized mass or heat transfer coefficient almost independent of ϕ, the angle of incidence between the leaf and the airflow, Cd, however, made up of a bluff‐body or pressure part Cb, in addition to a molecular skin friction part Cf, depended strongly on ϕ. C0 was close to the theoretical skin friction drag coefficient at ϕ = 0 of a thin flat plate with dimensions similar to the leaf. As a general relation between the corresponding coefficients of a natural rough surface CF = βC0, where β lies between 0·1 and unity, depending on the form and inclination (ϕ) of the roughness elements, and on wind speed.C0 was shown experimentally to be proportional to (wind speed)−1/2 in a regime of fully‐forced convection. When the evaporation from one side of the leaf was stopped, the transfer coefficient for the removal of vapour from the other side increased by about 30 per cent. An accurate form of the psychrometric constant of the leaf includes the factor (k/D)2/3, which has the value 0·90 for water vapour.
Response curves in the theory of atmospheric oscillations
Authors: Giwa F. B. A. 
Published: February 2007

AbstractIt is shown that response curves are characterized by several maxima and minima. With an upper boundary condition which involves total reflection of tidal energy the maximum magnifications are unbounded. With energy propagating upwards at the upper boundary the maximum magnifications are finite and decrease in value with decreasing successive resonant equivalent depths. Thus the first three maxima occur at equivalent depths equal to 9·94 km, 6·71 km, 3·4 km, with magnifications of 9,220, 10 and 1·7 respectively. A minimum magnification of 0·57 occurs at lunar semidiurnal equivalent depth (7·1 km). This is not adequate to explain the observed lunar tide.The features of the response curve are explained through a two layer model atmosphere. It is shown that the values of magnification at small equivalent depths are critically affected by the particular boundary condition whereas at large equivalent depths magnification is insensitive to variations in the top boundary condition.
Midwinter warmings in the upper stratosphere in 1966
Authors: Labitzke Karin 
Published: February 2007

AbstractRecently produced daily 5‐mb maps of the whole Northern Hemisphere for the first quarter of 1966 have revealed differences between the middle and upper stratospheric circulation – at least during certain periods over certain regions.Stratospheric midwinter warmings at the 5‐mb level (35 km) are compared with the circulation at the 10‐mb level (30 km) and material is presented showing that major warmings occur in the upper stratosphere without being noticed at the 10‐mb level–the highest level reached regularly by radiosondes.The need for the exploration of the levels between 30 and 60 km with higher‐reaching radiosondes and more rocketsonde data is emphasized.
Application of the technique of ionospheric drift analysis to the study of atmospheric turbulence
Authors: Paltridge G. W. 
Published: February 2007

AbstractAn analysis similar to that used in the study of the behaviour of ionospheric irregularities by spaced radio receivers can be performed on the output of sensors suitably spaced in a turbulent medium. A pilot experiment is described in which a 3‐channel, microwave refractometer was mounted on a 10 m tower. The three open sampling cavities were disposed at the corners of a triangle in a vertical plane parallel to the wind direction. The results are analysed to show the usefulness of the technique for giving a picture of refractive index fluctuations in terms of the average eddy size, shape, orientation and speed and direction of movement. The technique also yields a quantitative measure of the validity of Taylor's hypothesis. A 4‐channel refractometer has been built to obtain extensive 3‐dimensional results.
Rossby waves with negative equivalent depths – comments on a note by G. A. Corby
Authors: Lindzen R. S. 
Published: February 2007

AbstractThe results of Corby (1967) on the effect of constant angular zonal velocity on Rossby‐Haurwitz waves in a barotropic fluid layer are extended, in an approximate manner, to waves in an infinite compressible atmosphere. It is shown that the main effect of a constant zonal basic flow in the wave equation is to doppler shift the wave's frequency. However, an important non‐doppler effect enters into the lower boundary condition. The lower boundary condition determines the free oscillations' equivalent depths which now depend on the horizontal wave numbers and can be negative – consistent with Corby's results. For the atmosphere, the more negative the equivalent depths, the more tightly the oscillation is confined to the ground.
The disintegration and electrification of charged water drops falling in an electric field
Authors: Abbas M. A. , Latham J. 
Published: February 2007

AbstractThe spheroidal assumption employed by Taylor (1964) has been applied to a theoretical treatment of the deformation and disintegration of charged water drops falling through an electric field of strength F. Aerodynamic and hydrostatic pressure‐difference terms were incorporated into equilibrium equations from which the fields required to produce instability were determined. Values of F (Ro/T)1/2 required for disintegration were computed as a function of the applied charge Q, undistorted drop radius Ro and surface tension T. The predicted values of F (Ro/T)1/2 have been tested experimentally for positively or negatively charged water drops of Ro ranging from 0·10 to 0·17 cm falling through horizontal or vertical fields at temperatures varying from + 20 to −18°C. The agreement between theory and experiment was found to be good; the maximum discrepancy of about 3 per cent was obtained with the largest drops utilized and is probably a consequence of the oscillation factor discussed by Ausman and Brook (1967). As predicted, the field required to disintegrate a falling drop was found to be markedly dependent upon the magnitude of the charge that it carried. It is shown that the field, F, required to effect the disintegration of the great majority of charged raindrops falling through the intense electric fields of a thunderstorm can be expressed in electrostatic units to within an accuracy of 2 per cent by the equation F (Ro)1/2 = 13·6 – 8Q.The mass loss accompanying the disintegration of falling drops was found to bear a similar relationship to the field strength as was previously observed by Latham (1965) and Matthews (1967). Measurements on suspended drops of water showed that the valués of charge and mass loss, q and δM respectively, accompanying the disintegration are close to the theoretical maxima. The close parallelism between the experimental curves of q against Q and δM against Q suggests that instability occurs over a large fraction of the surface area of the lower hemispheroid.
On wind and shear stress profiles above a change in surface roughness
Authors: Taylor P. A. 
Published: February 2007

AbstractThe problem of determining the distribution of velocity and shear stress in the flow above a surface with an abrupt change in roughness is considered by using the ‘mixing‐length’ theory to relate the shear stress to the velocity profile and solving the resulting system of partial differential equations numerically. The results are compared with those obtained by Panofsky and Townsend (1964) and Taylor (1967), by assuming special forms for the velocity or shear stress profiles.
A major low‐level air current near the Indian Ocean during the northern summer
Authors: Findlater J. 
Published: February 2007

AbstractIt is demonstrated that high‐energy flow, in the form of low‐level southerly jet streams which have been reported earlier over Kenya, is only one part of a much more extensive current of air which flows rapidly around the western half of the Indian Ocean during the northern summer. The high speeds are associated with the concentration of the cross‐equatorial airflow into the zone from longitude 38 deg E to about 55 deg E instead of being rather evenly distributed from 40 deg to 60 deg or 80 deg E as illustrated in many climatological atlases and charts of mean flow during the season. The high‐speed current is shown to flow intermittently from the vicinity of Mauritius through Madagascar, Kenya, eastern Ethiopia, Somalia and thence across the Indian Ocean to the west coast of India and beyond. The stream is occasionally reinforced by northward flow through the Mozambique Channel.The high‐speed air current, or system of low‐level jet streams, is closely associated with the Intertropical Convergence Zone over the Arabian Sea and western India, and variations in the strength of the stream over Kenya during a two month period were related to the rainfall which western India received from the south‐west monsoon.
Numerical experiments on the formation of a tornado funnel under an intensifying vortex
Authors: Wippermann F. , Berkofsky L. , Szillinsky A. 
Published: February 2007

AbstractA tornado‐like vortex, which intensifies with time, is imposed on the upper boundary of the boundary layer. The downward development of this axisymmetric vortex is studied by numerical integration of the flow equations. The contour of the visible tornado funnel has been computed for various times. The streamlines, the field of pressure deviation, and of the tangential velocity are presented for a time close to the steady state. The influence of a varying eddy diffusion coefficient is investigated.
Fall velocities of plate‐like and columnar ice crystals
Authors: Jayaweera K. O. L. F. , Cottis R. E. 
Published: February 2007

AbstractThe Reynolds number of cylinders and discs falling in a viscous liquid was determined experimentally for values of the Best number (the product of the drag coefficient and the square of the Reynolds number) ranging from 1 to 104. The results were used to calculate the terminal velocities of plate‐like and columnar ice crystals.
A comparison between laboratory and atmospheric density currents
Authors: Simpson J. E. 
Published: February 2007

AbstractSome known results on density currents in liquids are discussed, and the geometry of the frontal regions and of the upcurrents in the region ahead of them is shown to be similar to that of some thunderstorm outflows and sea‐breeze fronts. The detailed structure of the frontal region of laboratory density flows is described. An internal Froude number has about the same value in the model and in the atmosphere.
A global analysis of the variability of the quasi‐biennial oscillation
Authors: Dartt D. G. , Belmont A. D. 
Published: February 2007

AbstractMonthly‐mean zonal wind data from approximately 200 rawin stations have been filtered to remove the annual and shorter period variations. Data from 1950–1964 for levels from 700 to 7 mb were analysed. The primary variation is the quasi‐biennial oscillation of the equatorial stratosphere and its extension to higher latitudes. There is much greater variability with longitude and time of the weak quasi‐biennial oscillation at higher latitudes than observed in the equatorial stratosphere. However, as the vertical and meridional phase progression patterns of the oscillations in both troposphere and stratosphere are systematic, these properties are probably real. The main fluctuations can frequently be traced from the surface to at least 35 km except in the middle latitudes of the Northern Hemisphere where the stratospheric variations often do not appear related to those of the troposphere. The most organized phase progressions with latitude are the apparent opposite ones observed in the stratosphere and troposphere of the Northern Hemisphere. Prior to 1960, well‐defined poleward progression is observed in the troposphere (300 mb), while weaker Equatorward progression is evident in the stratosphere (30 mb). In 1961 the pattern reverses, with poleward progression at 30 mb and Equatorward progression at 300 mb. In the tropical stratosphere during the years 1960–1961, the quasi‐biennial oscillation was characterized by unusually low amplitude, short‐period fluctuations.