bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of wind stress on the surface of Lough Neagh by measurement of tilt
Authors: Darbyshire J. , Darbyshire Mollie 
Published: February 2007

AbstractContinuous records of water level were taken at four points on the perimeter of Lough Neagh in N. Ireland during April 1949. The values of level at each point were measured over three‐hourly intervals to eliminate the effect of seiches and the differences in the values of level so obtained were found for all pairs of stations and are correlated with the wind speed and direction. The temperature difference between water and air is taken as a measure of the atmospheric stability.It is shown that atmospheric stability has a very marked effect on the tilt of the water surface due to the wind, the slope of the surface for a given wind speed (measured at a height of 12 m over land near the Lough) being about twice as great in unstable conditions as in stable conditions. It is also shown that the stress coefficient C increases with the length of water under the action of the wind under all conditions of atmospheric stability.Surface waves were also measured on the lake over this period but no conclusive evidence could be obtained to show that atmospheric stability has any effect on the generation of surface waves by the wind.
The salinity of rainfall as a function of drop size
Authors: Turner J. S. 
Published: February 2007

AbstractMeasurements of the salinity of raindrops as a function of drop size show that there are characteristic variations according to the type of rain. For Bergeron‐type rain near Sydney, New South Wales, the dependence may be expressed in the form salinity α (radius)−n, where n is a positive constant which is small when the cloudbase is low and as high as 2·6 for collection well below the cloud. The mean salinities over all drop sizes range from 1 to 41 parts NaCl per million. The main features of the experimental results are explained by a theoretical treatment which takes into account evaporation and the collection of salt below the cloud.For rain from warm clouds in the Hawaiian Islands, the salinity has a pronounced minimum at a certain drop size near the median. The daily mean salinities decrease with increasing distance inland, along the direction of trade‐wind flow, from 2·0–20 parts per million sodium chloride near sea level to 0·34–8·5 pt/mn near mean cloud base (2,100 ft) and 0·26–3·8 pt/mn at 4,500 ft. The salinity minimum occurs in samples at all three positions and secondary processes below the cloud cannot account for it; nor can it be a result of averaging the considerable variations of salinity which are found to occur from shower to shower.It is suggested as a possible explanation that the largest cloud drops might form on giant salt nuclei and grow to raindrop sizes first by coalescence with one another. This receives support from measurements on single showers, which show that the first raindrops to fall are large and have a high salinity. A detailed interpretation would seem to require a knowledge of the salt concentration in individual cloud drops.
Theoretical studies of diurnal wind‐structure variations in the planetary boundary layer
Authors: Buajitti K. , Blackadar A. K. 
Published: February 2007

AbstractAverages of the wind vector at four times of the day were evaluated for 29 suitable days during the summer of 1951 at Wichita, Kansas, and Oklahoma City. The periodic portion of the wind variation vector is an ellipse at all levels with the major axis approximately in the direction of the wind vector. The amplitude reaches a maximum at 2,500 ft above the ground.The cause of the variation is sought by theoretical methods, first by finding what periodic variations would occur when the eddy viscosity is periodic in time and constant with height, and secondly by finding solutions with the aid of an electronic analogue computer for cases when the eddy viscosity is distributed arbitrarily with height. It is concluded that variations of the type which were observed can occur only when both the average value of the eddy viscosity and the amplitude of its variations decrease rapidly with height above the lowest third of the friction layer.
Seasonal and other temperature changes in the Antarctic atmosphere
Authors: Wexler H. 
Published: February 2007

AbstractThe annual variation of temperature in Antarctica has interesting properties: it is largest in the stratosphere (50° to 60°C), smaller at the surface (20° to 40°C) and smallest in the troposphere (10°C). During the winter night the troposphere temperature decreases only slightly while the stratosphere temperature drops steadily at about 1/4°C per day. This differential cooling, which weakens and at times wipes out the tropopause, is caused, on the one hand, by intense horizontal advection of maritime air into the Antarctic troposphere, and, on the other hand, by very little advection through the strong stratospheric jet stream encircling Antarctica.This ventilation of the Antarctic troposphere by warm marine air causes large portions of Antarctica to exhibit the kernlose winter‐temperature curve instead of the sharp winter minimum usually found in polar continental climate. Anomalously high June temperatures in the lower troposphere at Little America are attributed to intense cyclones which form in the Ross Sea area and advect air from the lightly ice‐clad or open ocean located not too far north of the Ross Sea.Large deviations in average monthly temperatures are found in the Ross Sea area which are undoubtedly a reflection of large year‐to‐year circulation changes in that area.The Antarctic and Arctic stratospheres exhibit quite different temperature behaviours after the winter solstice. The Antarctic stratosphere continues to cool until the sun returns and then warms as much as 50°C in 1 month. On the other hand, the Arctic stratosphere exhibits a warming of 30° to 40°C, sometimes beginning 6 weeks before the sun returns.A secular trend of temperature since 1912 of + 2·6°C at Little America (78° 12'S, 162° 15′W) compares with a + 6·2°C trend at Spitsbergen (78° 04′N, 13° 38′E).Finally, temperature and outgoing radiation observations made at the South Pole I.G.Y. Station during the cold period of 19‐24 April 1958 are presented to illustrate quantitatively the important effect of warm cloud radiation on surface air temperature and its vertical gradient.
Total ozone and the middle stratosphere over arctic and sub‐arctic areas in winter and spring
Authors: Godson W. L. 
Published: February 2007

AbstractIt is well known that the arctic stratosphere customarily exhibits a rapid transition from winter to summer which has a permanent warming effect on stratospheric temperatures and causes a marked decrease in the intensity of the circulation at mid‐stratospheric levels. Prior to this final warming, temporary warmings occur with a marked effect only in sub‐arctic areas. These phenomena are closely related to the rapid increase in total ozone which takes place in the late winter and early spring in polar regions. The major ozone maximum occurs at the time of the final warming, with a magnitude dependent on the intensity of the rapid warming at high levels in the stratosphere. Earlier baroclinic waves during the winter cause closely correlated ozone changes, resulting in a stepwise increase in ozone prior to the final warming.10‐day running means of total ozone and of 100 mb temperature are compared for stations in northern Europe and in Canada; these reveal the relations between long‐period changes and processes in total ozone and in the middle stratosphere. In particular, one may thereby explain the seasonal behaviour of total ozone, which departs so markedly from photochemical prediction, as well as the vital dynamical role played by active centres in the stratospheric warm belt (especially in the Aleutian area) in the production of warm ozone‐rich stratospheric air masses.
Some computations of the variation of vertical velocity with pressure on a synoptic scale
Authors: Knighting E. 
Published: February 2007

AbstractThe vertical velocity in pressure co‐ordinates is computed from synoptic data on two occasions for each 100 mb interval between 1,000 mb and 200 mb at the points, approximately 160 mi apart, of a mesh covering much of the Atlantic Ocean and Europe. The assumptions made are that the mean lapse rate is everywhere the same, that there is little movement of air through the upper and lower pressure surfaces and that the horizontal wind is approximately geostrophic. The results show that the vertical profile is approximately parabolic with respect to pressure in regions of great development, but that elsewhere the profiles are not of a simple shape.
A theoretical investigation of the sea breeze
Authors: Estoque M. A. 
Published: February 2007

AbstractA primitive equation model is formulated and integrated numerically to study the sea breeze. The formulation is an extension of an atmospheric boundary‐layer model previously developed for a homogeneous terrain. External gravity‐wave type solutions are suppressed by a modelling assumption involving the equation of continuity. The results of an integration showing the evolution of the sea breeze under conditions of no large‐scale synoptic motion are presented.
An empirical method for estimating long‐wave radiation exchanges in the British Isles
Authors: Monteith J. L. 
Published: February 2007

AbstractFrom radiation measurements at Kew Observatory (tabulated by Lönnqvist), the effective emissivity of the atmosphere ε, defined as the ratio of incoming long‐wave radiation to black‐body radiation at screen temperature, can be related to optical path m (cm) by

With standard deviation ± 0·018. The relation between m and surface vapour pressure e (mb) found from Belasco's (1952) air mass analysis is

giving

almost the same as Brunt's equation from Benson data.Net long‐wave radiation L over short grass can be calculated from

where c is fractional cloudiness; σTA is black‐body radiation at screen temperature; ΔL1 is a correction for the difference between TA and cloud‐base temperature; and ΔL2 for the difference between TA and surface radiative temperature. From Roach's Kew data, ΔL1 = – 18 cal cm−2 day−1 and ΔL2 varies with season from – 12 cal cm−2 day−1 (December) to + 20 cal cm−2 day−1 (June). Throughout the British Isles, annual mean L with c = 0 is close to – 200 cal cm−2 day−1, and for real values of c

Estimated annual net (total) radiation is 29 k cal cm−2 with little variation over the British Isles.
The wake capture of water drops in air
Authors: Woods J. D. , Mason B. J. 
Published: February 2007

AbstractA technique is described for evaluating directly from a single streak photograph the impact parameter for a collision between two falling water drops of similar size. Collision results from one member of a pair of drops being accelerated in the wake of the other. An analysis of many such photographs allows the collection efficiency to be determined. No coalescences were observed between droplets of radius R < 35 μ. Droplets of 40 μ < R < 100 μ had well‐developed wakes, and coalescences occurred relatively frequently, the collection efficiencies being close to unity. No evidence is found for the much larger values of collection efficiency reported by other workers. Collisions between droplets of this size appear always to be followed by coalescence.
Precipitation and cloud electricity
Authors: Reiter R. 
Published: February 2007

AbstractBased on the evaluation of atmospheric electricity data recorded synoptically over a period of several years in a high‐mountain area between 600 and 3,000 metres above sea‐level, observations of the behaviour of several atmospheric electricity parameters are briefly presented. Besides providing information on charge separation occurring during drifting snow and on cloud charges, the results show the fundamental importance, with respect to atmospheric electricity phenomena, of the melting zone of falling precipitation and of the intensity of atmospheric turbulence and its dependence on altitude. A generally applicable mathematical formulation is given for the relation between the potential gradient and the precipitation current density. This is valid for both low and high altitudes above sea‐level and takes the differences between different types of precipitation into account.
The mass loss of water drops falling in electric fields
Authors: Latham J. 
Published: February 2007

AbstractExperiments showed that water drops of radius 0.191 cm falling for 0.2 seconds through a horizontal electric field were disrupted and lost mass if the field strength exceeded 8,500 V cm−1. As the field strength was increased above this critical value the mass loss increased rapidly and in a field of 11,500 V cm−1 the drop lost about 35 per cent of its mass; for higher values of field strength the mass loss increased more slowly.Experiments also showed that the magnitude of the mass loss was dependent upon the time of exposure of the drop to the field. For exposure times less than about 2 × 10−2 sec drops falling in a field of 11,250 V cm−1 lost no mass but as the exposure time was increased above this value the mass loss increased rapidly and for an exposure time of about 0.1 sec the mass loss was 25 per cent; for longer exposure times the mass loss increased more slowly.An assessment is made of the importance of this disruption process in modifying the concentration and size distribution of raindrops and cloud droplets inside a thundercloud.
Noctilucent clouds and thermospheric dust: Their diffusion and height distribution
Authors: Chapman S. , Kendall P. C. 
Published: February 2007

AbstractRocket sampling in latitude 66°N has shown that at heights around that of the mesopause, dust nuclei are far more abundant there when noctilucent clouds (hereinafter abbreviated to NLC) are present than when they are absent. The dust particles appear to be nickel‐based micrometeorites, and many of them, when NLC are present, appear to be ice‐coated. Hence the occurrence of NLC seems to require an adequate density of both water vapour and dust. The water vapour is supposed to rise to the mesopause by convection (in summer in latitudes above 45°); thence it diffuses into the thermosphere, where its upward penetration is limited by dissociation by ultra‐violet light, so that its effective scale height is estimated to be less than 2 km. Assuming that the air just above the mesopause is non‐turbulent, the scale height of the uncoated dust passing steadily downwards there is the same as that of the air, about 4.5 km. The estimated scale height of the NLC particles is about 1.5 km. Eddy diffusion below the mesopause causes the number density of both NLC and uncoated dust particles to decrease sharply just below the mesopause. Thus both the thinness and the location of NLC are explained.The diffusion problems considered refer to both the dust and the water vapour; the recent study of dust diffusion by Yu and Klein (1964) is extended. Also the influence of upward dust convection is considered. Conclusions are drawn as to the form of the NLC particles from their estimated rate of descent.The appearance of NLC is ascribed to the simultaneous occurrence (mainly, if not exclusively in the higher latitudes in summer) of a descent of the turbopause to the mesopause, a low mesopause temperature, and humid air below the mesopause.
Vertical structure of turbulence
Authors: Panofsky H. A. , Singer I. A. 
Published: February 2007

AbstractBased on fluctuation statistics from the Brookhaven tower, statistical models are presented which permit estimation of cross‐spectra between wind components at various heights. It is shown that a similarity hypothesis, proposed by Davenport (1961), seems to be valid.The upper portions of turbulent eddies are downwind of the lower parts, with slopes of order unity, probably dependent on wind shear.
Secular and other changes of atmospheric electrical potential gradient at Lerwick
Authors: Hamilton R. A. 
Published: February 2007

AbstractThe atmospheric electrical potential gradient at Lerwick is very much higher in stable airstreams from north‐west Europe than in other airstreams. The secular decrease in the general level of potential gradient began at the same time as at Eskdalemuir, and the gradient has now fallen to about one half of its value around 1950.
One‐dimensional spectra derived from an airborne hot‐wire anemometer
Authors: Payne F. R. , Lumley J. L. 
Published: February 2007

AbstractVelocity fluctuations in the flight path direction were measured by a single hot‐wire mounted in the wing tip of a light aircraft. Magnetic tape recordings were later analysed by standard means to produce one‐dimensional spectra. These spectra exhibited the (– 5/3) power law behaviour over a range of several decades of wavenumber. Local isotropy was verified in the horizontal plane by flight paths into and perpendicular to the mean wind.
A 10‐level atmospheric model and frontal rain
Authors: Bushby F. H. , Timpson Margaret S. 
Published: February 2007

AbstractA 10‐level primitive equation model suitable for studying the dynamics of fronts and frontal rainfall is described. The atmosphere is assumed to be hydrostatic and inviscid and the effects of friction and topography are ignored. Latent heat due to evaporation and condensation is incorporated in the thermodynamic equation. No distinction is made between the ice and water stage and the atmosphere is assumed to be dry above 300 mb. The horizontal grid length is 40 km. The results of one 24‐hr integration are described in detail.
Deposition of particulate matter by hydrometeors
Authors: Starr J. R. 
Published: February 2007

AbstractA recent paper by Starr and Mason (1966) described experimental determinations of the collection efficiencies of water drops and of simulated snow crystals for small, roughly spherical particles in the form of spores and pollen grains. Using these data and additional information obtained from observations on the impaction of particles on sticky spheres in a wind tunnel, calculations are presented for the rates at which particles of these sizes would be removed from the atmosphere by impaction on raindrops and snow crystals as a function of precipitation intensity. The raindrop scavenging results are compared with those of earlier computations by Chamberlain (1953) who used the theoretically derived values of collection efficiency by Langmuir (1948) and applied an intuitive equation suggested by Langmuir to interpolate between viscous and potential flow solutions for the collection efficiency.
The energetics of the lower stratosphere including radiative effects
Authors: Dopplick T. G. 
Published: February 2007

AbstractApproximate solutions of radiative heating are developed using monthly mean radiative parameters and are combined with the geopotential and temperature fields to study the energetics of the Northern Hemisphere lower stratosphere on a daily basis for 1964. Significant leakage of energy from the troposphere occurs throughout the year and absorption of this energy in the lower stratosphere contributes to the maintenance of the eddies for all months except January. In winter there is significant transmission of tropospheric energy into the upper stratosphere which suggests a close coupling of the upper and lower atmospheres. The seasonal circulations are examined and it is found that the spring warming of 1964 was due to a period of enhanced convergence of tropospheric energy flux. In the fall absorption of tropospheric energy intensifies the flow. The role of radiation is to destroy available potential energy for all months of the year.
The development of a dry inversion‐capped convectively unstable boundary layer
Authors: Carson D. J. 
Published: February 2007

AbstractA model is proposed for the development of a dry convectively unstable boundary layer capped by a stable layer; included are the effects of time‐dependent surface heating, the stability of the capping layer, subsidence and any degree of turbulent interfacial mixing. A differential equation describing the evolution indicates quantitatively the relative importance of each factor and, in particular, indicates the importance of the entrainment process. The model is applied to the 1953 O'Neill boundary layer data in an attempt to assess to what degree interfacial mixing is realized in the atmosphere. Realistic boundary layer developments are obtained.
A study of the continuum absorption within the 8–13 μm atmospheric window
Authors: Lee A. C. L. 
Published: February 2007

AbstractThe spectral continuum within the 8–13 μm atmospheric window was studied using a tethered balloon borne radiometer, while simultaneous measurements of temperature and humidity profiles were made. Aerosol absorption was estimated as negligible as the measurements were made in conditions of high visual range. The results from a range of situations were tested separately against a line wing continuum model and a water dimer continuum model, both with appropriate spectral line band models. These results were found to agree well with laboratory data for the dimer model.
Stratospheric temperature anomalies in 1963 and 1966
Authors: Pittock A. B. 
Published: February 2007

AbstractThe existence, statistical significance, and possible causes of stratospheric temperature anomalies observed at the 100 mb level in the Australasian region in 1963 and 1966 are discussed with reference to the so‐called quasi‐biennial oscillation, volcanic dust, and the general circulation. This discussion is facilitated by the use of the observed correlation between stratospheric temperatures and the mean latitude of the surface high pressure belt, in order to increase the sensitivity of a statistical test for anomalous temperatures.
Planetary‐scale disturbances in the polar winter stratosphere
Authors: Simmons A. J. 
Published: February 2007

AbstractSome models of steady planetary‐scale disturbances forced in the winter stratosphere by tropospheric pressure perturbations are presented for zonal flows with both vertical and meridional shear. The resulting structure of these disturbances is realistic. In particular, they are confined in the horizontal to regions of strong westerly wind, and do not exhibit a deficient vertical penetration, results in contrast with some earlier studies. Examples are included in which amplitudes are insensitive to the presence of either a strong New tonian cooling or singular‐line absorption.The time‐dependent behaviour of stratospheric planetary waves is examined for a zonal wind with uniform vertical shear. Analytical solutions emphasize the importance of a low‐level conversion of zonal available potential energy in amplifying a disturbance forced at the tropopause. When allowance is made for the meridional structure of the stratospheric jet, a reasonable agreement is obtained between theory and observation, in particular with respect to perturbation geopotential heights observed in sudden warmings.