bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparison of different types of stress measurement
Authors: Panofsky H. A. 
Published: February 2007

AbstractWind stresses computed from the profile of the mean wind at Brookhaven are compared with Reynolds stresses at 109m. Two methods are used to obtain the surface stress from the mean winds: one is based on three observations up to 125 m, the second on the observation at the lowest level only, as well as a roughness length determined previously.The stresses found by both these techniques agree in order of magnitude with the Reynolds stresses, varying from about 1 to 10 dynes cm−2. With respect to actual numerical values, only the wind stress determined from the lowest‐level wind agrees well with the Reynolds stress.
The production of showers by the growth of ice particles
Authors: Ludlam F. H. 
Published: February 2007

AbstractA model of cumulus‐cloud structure is described, and used, together with the available evidence on the temperatures of ice‐crystal formation and a calculation of the speed of growth of crystals into precipitation elements, to estimate the summit‐level temperatures at which the formation of showers becomes likely. It appears that in warm weather showers may be expected with summit temperatures of about −10°C, but in cold weather not until they fall to about −20°C. Observational evidence is shown to support this view although emphasizing large casual variations, some of whose causes are suggested.
On the velocity, temperature, and humidity profiles in the lower atmosphere
Authors: Björgum O. 
Published: February 2007

AbstractOn the basis of the assumption that the eddy viscosity, eddy conductivity, and eddy diffusivity are determined by the first and second differential coefficients of the mean velocity U, mean potential temperature Θ, and mean humidity X (specific humidity, mixing ratio, or water‐vapour pressure) the following formulae are obtained for the lower atmosphere over level ground (valid up to a height of about 25 m),

Here Θ, and X0 denote potential temperature and humidity at the ground. U* is the friction velocity and Θ* and X* denote corresponding quantities for temperature and humidity.The above logarithmic formulae are in good agreement with Best's measurements when the parameters d, a, b, k, l are chosen to give the best fit with his observed velocity and temperature profiles which are grouped according to stratification and mean velocity.The zero‐plane displacement d is inferred to be the same for all profiles. Measurements by Sverdrup indicate that this is true for for temperatures whereas measurements by Rider and Robinson indicate that it is not always true for higher temperatures.Theoretical reasoning leads to the conclusion that d should increase with thermal instability and this is verified by Best's data. It is also inferred that k, l, and m should increase with instability, whereas a is found to decrease with instability.
Annual recurrences in Edinburgh temperature
Authors: McIntosh D. H. 
Published: February 2007

AbstractMean daily temperatures at Edinburgh for a period of 150 years are examined for evidence of persistent annual recurrences of unseasonal character. The recurrences are found to be very largely casual in their incidence but, as a result of tests applied, it is concluded that there is only a very small probability that their nature is completely random. Recurrences on the days of ‘Buchan spells’ are found not to depart to a significant degree from chance expectations.
The growth of raindrops in cloud
Authors: Adderley E. E. 
Published: February 2007

AbstractA method is described by which the rate of growth of raindrops in cloud is deduced from the results of a balloon‐borne radio transmitter. The transmitter, during its passage up through the cloud, gives a continuous record of the drop‐size distribution of the rain. The values of the rates of growth of raindrops obtained in this manner differ considerably from those computed from accepted values of cloud‐drop distributions and raindrop‐collection efficiencies. The experimental values rise more rapidly than the computed values by a factor of from 3 to 4 in the 0.5 mm to 1.0 mm raindrop‐diameter range.It is concluded that the effect is real but, as yet, knowledge of the physical conditions within a cloud is insufficient to suggest a mechanism to account for it.
Fluctuations of temperature below cumulus clouds
Authors: James D. G. 
Published: February 2007

AbstractA description is given of one flight below cumulus clouds on 28 Aug. 1952. Small rapid fluctuations of temperature were observed by a sensitive resistance thermometer, records being obtained as a photographic trace. It is shown that, with respect to the frequency and type of fluctuation of temperature encountered, the space between cloud base, i.e., 3,100 ft, and ground level may be divided into three sections. The first, a layer extending from ground to about 800 ft, the second from 800 ft to about 2,800 ft, and the third from 2,800 ft to cloud base. A possible explanation for the formation of these layers is discussed.
The formation of atmospheric ice crystals by the freezing of droplets
Authors: Bigg E. K. 
Published: February 2007

AbstractUsing the results of laboratory experiments on the supercooling of purified water, the freezing of cloud and raindrops is examined. It is shown that at temperatures lower than about −30°C in cold‐box or expansion‐chamber experiments, the drops freeze in approximately the numbers that would be expected if they were pure water. Those that freeze at temperatures higher than about −20°C seem to be more numerous than would be the case if the drops were pure. An interpretation of the main features of the Findeisen and Schulz expansion‐chamber experiments is found to be possible without appealing to the action of foreign ice‐forming nuclei, although there is a discrepancy between calculation and experiment at temperatures higher than about −20°C. In the atmosphere, formation of cirrus clouds is shown to become possible at temperatures below about −35°C, glaciation in stratiform clouds to become appreciable at temperatures below about −20°C and freezing of raindrops in strongly convective clouds to become important below about −13°C, without the presence of ice nuclei. It is concluded that freezing nuclei may be important at temperatures above about −20°C, while their presence at lower temperatures will be masked by the freezing of uncontaminated drops.
Observations of rainfall from warm clouds
Authors: Mordy W. A. , Eber L. E. 
Published: February 2007

AbstractRainfall from non‐freezing clouds has been widely reported but detailed observations are sparse. During June 1952, ten days of observations were made during trade‐wind weather conditions on the island of Oahu. Rainfall was observed during each of the 10 days, and in no instance did cloud temperatures below 7°C occur. Aircraft were used to obtain temperature and humidity soundings supplementary to the Honolulu radiosonde and to measure the dimensions of the clouds. Raindrop sizes were recorded on a continuously moving dye‐treated paper tape at two locations. Data on rainfall were obtained from 5 recording raingauges on the crest of the Koolau Mountain Range and from 32 standard raingauges in an area of 130 m2 Pilot‐balloon ascents were made daily on the windward coast of Oahu to supplement the Honolulu Weather Bureau wind data. A continuous record of cloud conditions and motions was made by lapse‐time motion‐picture photography and supplemented with photographs from aircraft.Rainfall intensities exceeding 3 mm/hr were observed from clouds with bases at 2,000 ft (18.6°C) and tops at 7,500 ft (10.2°C). Raindrop sizes as large as 2 mm in diameter were observed from clouds 6,000 ft deep. Light‐intensity rains from small cumulus clouds frequently consisted of raindrops which were relatively large (2 mm diameter) but low in number.
Rainfall in the Isle of Man
Authors: Reynolds G. 
Published: February 2007

AbstractThe rainfall of the Isle of Man has been examined, making use of all available data, much of it relating to only very short periods. This discussion has been made possible by treating all the short records from the aspect of their differences on Douglas. The Island is divided into seven rainfall zones, the characteristics of which are discussed. Maps of the average annual fall and the average number of rain‐days and wet‐days are presented. Fluctuations of annual rainfall have been found to lie between 64 and 145 per cent of average. When compared with other Irish Sea coastal areas, the Douglas average rainfall is shown to be most closely correlated with that of the North Wales coast and South Scotland.
Evaporation from an oat field
Authors: Rider N. E. 
Published: February 2007

AbstractEvaporation from natural surfaces may be evaluated by a method based on aerodynamic considerations which lead to the simple equation magnified imagein which E, p and k are the rate of evaporation, the air density and von Kármán's constant respectively, u1, u2, q1 and q2 are the wind speeds and specific humidities at the heights z1 and z2, and d the so‐called surface zero displacement. This formula has been applied to observations taken over an oat field in order to determine the hourly values of E during a number of periods ranging in length from one to twelve days. The magnitude of d is shown to increase with increasing crop height and wind speed, the crop height increasing eightfold over the total period of observation. Daily water losses are calculated and found to vary from 0.05 mm to 5.65 mm. By using two sets of apparatus, the calculated values of E are shown, in unstable conditions, to depend on the height of exposure of the apparatus, decreasing with increasing height. A modified form of the equation, based on Deacon's generalized wind‐profile law, has been used in the last period of observation and found to reduce the dependence of the calculated values of E on the level at which the apparatus was placed. The general application of the modified expression was found to be impossible owing to insufficient precision in the measurements of the wind speeds and to the uncertainty in the value to be assigned to d. In general, the computed daily water losses are considered to be underestimated to an extent not exceeding 15 per cent.
Rainfall in relation to the jet stream
Authors: Johnson D. H. , Daniels S. M. 
Published: February 2007

AbstractA study is made of the rainfall occurring at four British stations on occasions when they lie beneath the jet stream. The mean distribution of rainfall in relation to the jet stream provides evidence, in agreement with dynamical theory, for a direct circulation at the jet entrance and an indirect circulation at the jet exit. Precipitation patterns found for uniform currents provide no satisfactory evidence with regard to the preferred vertical circulations within the central region of the jet stream.
A study of blocking in the Atlantic‐European of the northern hemisphere
Authors: Sumner E. J. 
Published: February 2007

AbstractVarious interpretations of what is meant by ‘blocking’ in the atmosphere are discussed. The three main aspects referred to by writers on the subject are: (a) a sharp local diminution of the mean zonal (tropospheric) flow, often associated with a bifurcation of the jet stream, which diminution is (b) rather persistent and (c) displaced westwards with time. Not all of these attributes have been insisted upon as defining blocking but usually (a) and (b) are required. The view is taken herein that, for forecasting purposes, only (a) is admissible, and a selection of instantaneous patterns having this characteristic is made, two broad types being distinguished, for the period 1949‐52 and in the Atlantic‐European sector of the northern hemisphere.Some statistics relating to the seasonal and geographic distribution of these patterns are given, which in the main confirm previous results. Blocking patterns were found to occur on more than half the days, individual blocks lasting on an average 16.5 days. They were most frequent in May and least frequent in July, and tended to be displaced from Europe to mid‐Atlantic during the first six months of the year. Within this general westward drift several successive ‘waves’ of progression and retrogression were in evidence. Blocking over N. America was extremely rare.This position and movement of individual blocks is presented in some detail, and notes on their formation, dissipation and general character are also given.
Theory of airflow over mountains: III ‐ Airstream characteristics
Authors: Scorer R. S. 
Published: February 2007

AbstractThe problem of what second boundary condition (the first being the ground profile) should be applied to the differential equation for the variation with height of the wave amplitude is considered and it is thought that solutions corresponding to upward and downward progressing waves are generally irrelevant. In practice we shall be concerned mainly with those waves of length such that their amplitude decreases with increasing height. Only when there is a considerable range of such wavelenghts is the motion of the kind supposed in the perturation theory.Though it is desirable to characterize an airstream by a single number this is not at present possible for airstreams in general, and it is shown by examples how airstreams may possess the same lee wave length though their l‐profiles differ considerably. These examples show that generally the maximum amplitude of the waves is found at or close to levels of maximum values of l, at sharp inversions in particular.The behaviour of lee (statopmaru) waves is fairly representative of mountain waves in general.
Snowfall probabilities on Merseyside
Authors: Reynolds G. 
Published: February 2007

AbstractThe probabilities of snowfall and snow cover on Merseyside are examined by computing adjusted normal frequency distributions for 34 years of record at Bidston, Wirral, about three miles from the centre of Liverpool. A graph has been drawn from which the chances of these occurrences can be read off directly for any selected date or period. Estimates are also advanced of the probabilities of deep snow lying on the ground. These have been computed principally from records of heavy daily rainfall.
Tidal oscillations of the lower stratosphere
Authors: Johnson D. H. 
Published: February 2007

AbstractIt is demonstrated that diurnal and semi‐diurnal variations of wind occur in the lower stratosphere. These oscillations appear to be associated with the solar tides. The stratospheric semi‐diurnal oscillation of wind is in phase with, and of comparable magnitude to, the surface semi‐diurnal oscillation of wind. In the stratosphere, the diurnal oscillation is found to be of similar magnitude to the semi‐diurnal oscillation.
The scintillation of radio stars
Authors: Palmer H. P. 
Published: February 2007

AbstractThis note presents a brief summary of the work of Little, Maxwell and Dagg (1952, 1954) on the fluctuations of the power received from the intense sources of radio emission in the constellations of Cassiopeia and Cygnus.Receiving equipments, 4 km apart, give almost identical records of the fluctuations, but there is no correlation when the receivers are 200 km apart. The fluctuations occur mainly during the night, the degree of fluctuation varying from night to night, and showing a close correlation with the occurrence of ‘spread F’ ionospheric echoes. This evidence suggests that the fluctuations are caused by a terrestrial agency, and not by variations of the power emitted by the radio source. It is thought that the fluctuations are analogous to the ‘twinkling’ of visual stars and are caused by a diffracting screen of irregularities above the maximum of ionization in the F region of the ionosphere.When records from receivers two or three km apart are compared, small time‐differences can be detected between the records of similar fluctuations. These may be interpreted as evidence for drift motions of the diffracting screen. Records from a triangularly‐spaced set of three stations have recently given both the drift speeds and directions. For observations when the source is near the zenith, in Britain, the velocities are usually in the range 50–300 m/sec, in an east‐west direction.In the winter months, when the stars transit near midnight, the drifts are towards the west before 01 GMT. There appears then to be a fairly sharp reversal, and the drifts are predominantly towards the east thereafter. As the fluctuations rarely occur in the daytime, no other reversal has been observed.When the stars are observed near lower culmination the line of sight passes through the F region in the auroral zone. Fluctuations are observed at all times (even on magnetically quiet days), and they indicate rather higher velocities, and more variable directions of drift. The drifts are predominantly towards the west in the period 09–21 GMT and towards the SE. or SW. from 21‐06 GMT. The apparent N‐S components of these drifts might be caused by vertical movements. The appended references contain full accounts of this work.
Low‐temperature fog at the Edmonton Airport as influenced by moisture from the combustion of natural gas
Authors: Robertson George W. 
Published: February 2007

AbstractThe Edmonton Municipal Airport, being within the city limits, is completely surrounded by a source of moisture from the combustion of natural gas. Since the natural gas is metered to consumers, a quantitative study of the injection of moisture into the air around the airport is possible. Equations and graphs show how moisture in the air at the airport is influenced by temperature, wind velocity and initial relative humidity. The results obtained are compared with fog conditions observed at the airport during the winter of 1949–50.
Secular changes of tropical rainfall regimes
Authors: Kraus E. B. 
Published: February 2007

AbstractSecular changes are demonstrated by residual mass curves. It is shown that tropical rainfall decreased abruptly at the end of the 19th century. This was due largely to a contraction of the rainy belt and a shortening of the wet seasons. In the SE. Asian monsoon region the annual rainfall has varied less than in the rest of the tropics but changes occurred in the seasonal pattern. Similarities in the records suggest a physical connection between frontal or cyclonic activity in the temperate zone and the October‐March monsoon rains of tropical Australia and SE. Asia.A concluding section develops the argument that the evaporation‐precipitation cycle is a partly unstable process and that small radiative changes could conceivably produce large and abrupt changes in the rainfall regime.
Methods of synoptic analysis at low latitudes
Authors: Watts I. E. M. 
Published: February 2007

AbstractThe apparent differences in the methods of synoptic analysis employed in the tropical Pacific and in equatorial SE. Asia represent nothing more than adaptations of the same technique. Over the Pacific it is unusual for two different air‐streams to meet at a large angle and, since their common boundary cannot be traced from day to day with continuity, reliance must be placed on recognition of short‐lived asymptotes and vortices from the instantaneous streamlines. Over equatorial SE. Asia, long semi‐permanent boundaries can be traced with continuity owing to the persistence of the westerlies. The difference of opinion as to the most desirable method of analysis is mainly due to the variations in horizontal extent of the equatorial westerlies in different longitudes. At the boundary between the trades and the westerlies there are separate centres of rainfall rather than a continuous rain‐band.
An operational frontal contour‐analysis model
Authors: Anderson R. , Boville B. W. , McClellan D. E. 
Published: February 2007

AbstractA three‐front model is proposed as a practical solution to analysis problems associated with both surface fronts and the baroclinic currents of the upper westerlies. They are called the ‘polar front,’ the ‘maritime front,’ and the ‘arctic front.’A front is defined as a three‐dimensional baroclinic zone, having a first‐order discontinuity in the temperature and wind fields, and being reasonably continuous in space and time. Frontal contour analysis is found to be operationally practicable and desirable.
The temperature profile above bare soil on clear nights
Authors: Lake J. V. 
Published: February 2007

AbstractA method of investigating air temperature profiles by means of a small unscreened thermistor bead is described. Profiles measured both with this equipment and with ordinary minimum thermometers under very stable atmospheric conditions exhibited unusual features inconsistent with the generally accepted theory of nocturnal cooling of the near‐ground air layers. The minimum air temperature was found to occur at heights varying between 1.5 and 6.0 in. above the surface, and the results support the view that direct radiation loss from the air is important in determining the temperature distribution under these conditions.
On the melting of hailstones
Authors: Mason B. J. 
Published: February 2007

AbstractCalculations have been made on the rate of melting of solid ice spheres and of graupel particles as they fall from the 0°C level towards the ground. Graphs are drawn for particles of various initial radii showing the radius of the unmelted core as a function of the distance fallen, and the distances which the particles must fall in order to melt completely. The effects of acquiring additional water by condensation and by the accretion of cloud droplets on the rate of melting of the particles are investigated.
Secular changes of the standing circulation
Authors: Kraus E. B. 
Published: February 2007

AbstractThe evidence produced seems to show a secular intensification of the North Indian summer‐monsoon low. The effects upon rainfall in North India and the Peninsula are discussed qualitatively. The secular decrease of the mean summer pressures in North India was associated with an increase of winter pressure. Similar pressure changes, with an even larger seasonal amplitude, occurred throughout eastern Europe, Siberia and eastern Asia.The secular increase in the seasonal pressure oscillation over the interior of Eurasia may have been associated with variations in the wind field which should tend to cause colder winters in the Far East and warmer, shorter winters in Europe. In summer the opposite tendency should prevail. An analysis of records confirms this inference.An intensification of the standing circulation of the northern hemisphere may have caused an increased transport of warm air into the Arctic and hence contributed to the retreat of the arctic ice. The absence of large‐scale standing oscillations in the southern hemisphere, accounts, probably, for the apparent absence of marked climatic change in the Antarctic.The strength of the standing monsoon‐type circulations appears to be in a roughly inverse relation to the strength of the zonal circulation. The resulting interaction could cause a large amplification of small disturbances in the climatic equilibrium.