bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rainfall at Bidston, 1867–1951
Authors: Reynolds G. 
Published: February 2007

AbstractThe 85 years (1867–1951) of rainfall record at the Liverpool Observatory and Tidal Institute, Bidston, are the longest uninterrupted series in NW. Cheshire. Their salient features are:(i) The mean annual rainfall in the calendar year is 28–68 in. with one exceptionally wet year, 1872, when 45.66 in. were recorded.(ii) The mean of the seasonal year is 28.74 in. In this case, although the standard deviation is larger than with the calendar year, the driest and wettest years are not so extreme.(iii) October, although it has been getting drier, is the wettest month, and April is the driest. The characteristics of the other months are scrutinized and compared following the computation of mean daily rainfall figures.(iv) The probability of a month being the wettest in any year is directly proportional to the cube of its mean rainfall.(v) The probability of a month being the driest in any year is inversely proportional to its mean rainfall.(vi) Spring is the driest season and autumn the wettest, summer having significantly more rain than winter.(vii) No significant correlation exists between one season's rainfall and any subsequent season's fall.(viii) There have been very few occasions of heavy rainfall, the maximum recorded in 24 hr being just over 2 in., and only three noteworthy falls. This is due to Bidston's geographical position, as it misses the most violent instability storms and is partially in the rain‐shadow of the Welsh mountains, which protect it from the heaviest depression rains.(ix) On the average there is an absolute drought once every 15 months and it is of 19 days' duration. Only two droughts have lasted longer than 26 days.(x) Frequency curve graduation of annual and seasonal rainfall proved disappointing, as few absolute conclusions relating to extreme values could be drawn from the figures owing to the large probable errors involved, with what, in a statistical sense, is a relatively short period of observations, only 85 years. Deductions based on such computed curves are, however, the best method of estimating rainfall probabilities.
On the physics of dusty atmospheres
Authors: El‐Fandy M. G. 
Published: February 2007

AbstractMeasurements of particle size and concentration of atmospheric dust have been made at Alexandria in various degrees of turbidity. Except for ‘dust haze,’ reasonable agreement is obtained between the measurements and Koschmieder's equation for visibility in terms of optical attenuation. In ‘duststorms’ the required attenuation implies a scatter coefficient per particle 8/3 times the cross‐sectional area of the particles, while in occasions of ‘dust’ the scatter coefficient implied per particle is 4 times the cross‐sectional area of the particles. The results are as follows:

Dusty atmosphere
Visibility (m)
Average concentration (cm−3)
Average particle diameter (μ)
90% of particles have diameter ≤ (μ)
Scatter coefficient per particle/cross‐sectional area of particles

Dust haze
5,000–6,000
200
0.5
1.3

Dust
2,000–2,500
330
1.3
2.0
4

Duststorm
750–1,000
550
2.0
3.5
8/3
A further study of the upper westerlies; the structure of the wind field in the eastern North Atlantic and western Europe in January 1950
Authors: Johnson D. H. 
Published: February 2007

Abstract(a) A study of 62 vertical cross‐sections through the middle‐latitude wind fields of January 1950 confirms previous conclusions regarding the broad structure of the upper westerlies.(b) A mean January section from Greenland to the Mediterranean contains a wind maximum of 60 kt at a height of 9 km, 61°N. Examination of mean winter‐flow patterns for the North Atlantic shows the mean south‐westerly jet stream to be a normal seasonal feature.(c) Comment is made on two features which require further study : high‐speed currents in the Arctic stratosphere and low‐latitude jet streams.
Computation of tendencies and vertical motion with a two‐parameter model of the atmosphere
Authors: Bushby F. H. , Hinds Mavis K. 
Published: February 2007

AbstractThe system of partial differential equations given by Sawyer and Bushby (1953) for the rates of change of the 1,000‐500‐mb thickness and the 500‐mb contour height have been solved on an electronic computing machine for three synoptic situations and the fields of vertical motion were also computed. The results, described in this paper, show reasonable agreement with actuality. The implied 1,000‐mb height tendencies also agree quite well with those actually observed.
A note on the use of the stereographic map projection in dynamical meteorology
Authors: Ellison T. H. 
Published: February 2007

AbstractThe equations of motion in curvilinear coordinates, in which the curvature of the earth is taken into account, are shown to be quite simple when the coordinate system is a particular one, closely related to the stereographic map projection. As an illustration of the use of these coordinates, derivations are given of the vorticity equation and of Ertel's Theorem.
Radiation and lag errors of the Meteorological Office radiosonde and the diurnal variation of upper‐air temperature
Authors: Scrase F. J. 
Published: February 2007

AbstractRadiation errors of the Meteorological Office radiosonde have been obtained from calculation of the rates of absorption of radiation and of heat loss by forced convection. the effect of the heating of the radiation shield on the temperture of the air reaching the thermometer element becomes very large at high levels. The errors due to direct solar radiation and to radiation reflected and emitted from below an ascending sonde have been calculated for different solar altitudes and for heights up to 30 km.At solar altitudes between 40° and 60° the errors amount to about 1°C, 2°5°C and 9°C at 5, 15 and 25 km respectively. Observed differences in readings from ascending and rapidly descending sondes indicated that the error at 25 km was withing about 7 per cent of the calculated value.Lag coefficients have been derived from the heat‐transfer coefficients and the calculated value for ground level is in good agreement with laboratory measurements.The errors of the radiosonde can account for the whole of the observed differences between day and night observtion up to 15 km. Above that height, however, the differences are appreciably greater than the errors and suggest that the daily range of temperature variation over the British Isles in spring and autumn is about 1.5°C at 20 km and about 3°C at 25 km.
The concentration, size distribution and production rate of large salt nuclei over the oceans
Authors: Moore D. J. , Mason B. J. 
Published: February 2007

AbstractThe sampling and measurment of large condensation nuclei (equivalent salt contents greater than 2 × 10−14g) on board of Weather Ships in the N. Atlantic, 200 mi from land, reveal the existence of two distinct types of size spectra. It seems that the nuclei which predominate when waves are breaking (Type I distribution) are the residues of spray droplets, but that those which occur with wind speeds of less than 7 m sec−1 have a (Type II) distribution which closely resembles that of continental aerosol. In winds of up to 15 m sec−1 the measured concentrations of large salt nuclei rarely exceeded 10/cm3.From the measured concentration and size distribution of Type I nuclei, it is deduced that in winds of 15 m sec−1 the rate of production at the sea surface of salt nuclei with mass greater than 10−13g is about 40 cm−2 sec−1; very similar values have been obtained from laboratory experiments in a wind‐wave tunnel. The corresponding rate for nuclei with m >2 × 10−14g would be about 100 cm−2 sec−1.Laboratory studies show that the bursting of air bubbles of diameters between 0.3 mm and 4 mm at the surface of sea water produces small numbers of rather large drops (diameters 50‐500μ), the majority of which would fall back quickly into the sea. The large salt nuclei found in the atmosphere are probably the residues of smaller drops produced by disintegration of the bubble caps.
The tilt of a 12‐hourly atmospheric tidal wave
Authors: Thrane P. 
Published: February 2007

AbstractForced oscillations of 12‐hr period, stationary relative to the sun, are considered in a model atmosphere enclosed in a canal coincident with the earth's equator. Two‐dimensional, inviscid motion is assumed. The study is based on equations of perturbation containing linear terms and second‐order product terms. The oscillations are excited thermally and gravitationally. In the general case such waves have a variation of phase with height, a ‘tilt’, and this is necessary in order that a vertical transport of energy may take place. In non‐tilting waves no tidal energy can be supplied to the model atmosphere. An adiabatic wave can have no tilt. The method of perturbation is applicable to the tilting waves only for a limited time interval.
Microclimatological profiles in grass cover in relation to biological problems
Authors: Waterhouse F. L. 
Published: February 2007

AbstractSelected climatic profiles, as measured by adapted meteorological techniques in the Angus area, were found in general to conform with work done elsewhere either in grass or corn fields. Seasonal and diurnal differences in air‐temperature stratification were related to height, density and mode of growth of crop, and solar altitude. The presence of a matted basal layer of dead grass in wild grassland, or the co‐existence of a clover crop in hay and silage fields, was noted to be important in maintaining a cool, humid atmosphere next to the ground. Such a zone was favourable to insects when arid conditions obtained at higher levels. In the upper regions where more edible grass leaves extend, wind was shown to be a most significant factor. This was due to the sudden reduction of wind speed within the crop. A steep gradient of wind speed, from zero to 90 or 100 cm/sec, might thus commonly be expected in the region some 40 cm to 15 cm below the upper surface of the stand under a variety of wind and grass conditions. Such a gradient could make available to an insect so situated a considerable range of body temperatures and states of water loss during periods of insolation. Field experiments, however, suggested that convective cooling often extended beyond the depth at which radiation intensity fell off greatly, since, in grass, insect body‐temperatures were frequently close to that of the surrounding air. The latter, however, was usually markedly different to that noted in a Stevenson screen. Wind conditions were also noted to be significant biologically wherever experimental procedure required the enclosure of grassland or the proximity of wind‐shielding hedges or walls. The ensuing alteration of microclimate particularly as regards air temperature might seriously upset the original purpose of such experiments, a fact noted by workers investigating other crops. Whilst figures quoted might provide a guide to the order of magnitude of some of the microclimatic phenomena encountered in the Angus area due regard should be paid to the lack of uniformity in most grass stands and the sometimes rapid variability of weather conditions.
A three‐front model for synoptic analyses
Authors: Penner C. M. 
Published: February 2007

AbstractA model for synoptic frontal analyses derived from frontal‐contour‐chart studies is described. Three frontal systems named the polar front, the maritime arctic front and the continental arctic front are necessary to portray adequately the thermal‐frontal structure of the atmosphere. In‐phase wave development on at least two of the frontal systems occurs during major cylogenesis. The three‐front (or four‐air‐mass) cyclone is verified by aerological analyses while the classical occlusion model is not usually observed.
The atmosphere between 85 and 105 km studied by means of radio‐echoes from meteor trails
Authors: Browne I. C. 
Published: February 2007

AbstractMeteors falling into the earth's atmosphere produce, by a process which was described briefly, a trail of ionised air. By studying the reflection of radio waves from these trails (‘meteor echoes’) the atmosphere at heights near 95 km can be sampled several hundred times per hour throughout the day, simply and at low cost. The paper summarized results obtained by many workers at Jodrell Bank since 1946 (see references).The intensities and heights of appearance of meteor echoes lead directly to estimates of air density (about 3 × 10−9 g/cm3 at 95 km) and of scale height (about 6·5 km at 95 km), while the durations of meteor echoes afford a means of measuring the atmospheric diffusion coefficient. The measurements were compared briefly with independent estimates.By a special technique, movements of meteor trails of the order of 1 m are detected, and hence winds measured at heights of the order of 95 km. Although ‘winds’ obtained by ionospheric methods may represent travelling disturbances, the ‘meteor’ winds are true mass movements of the air. It is found that there is usually a prevailing wind of the order of 10 m/sec, upon which is superimposed a semi‐diurnal variation which may have an amplitude of 30 m/sec. The phase and amplitude of the semi‐diurnal component show seasonal changes. The winds increase with height, the shear having a value of about 2 × 10−3 sec−1, a value comparable with that found in the troposphere, although there is no change in wind direction with increasing height. There is no detectable vertical component of wind.
Upper winds from geomagnetic observations
Authors: McIntosh D. H. 
Published: February 2007

AbstractThe belief that it may be possible to interpret geomagnetic observations in terms of upper atmospheric winds is based on the theory proposed by Balfour Stewart in 1882 to account for the observed daily magnetic variations. Balfour Stewart's suggestion was that the upper atmosphere is highly conducting and that this conducting air in its daily horizontal tidal movement across the vertical component of the earth's field induces by dynamo action a varying electric current whose magnetic field is observed at the ground as the magnetic daily variation. The theory of the magnetic solar daily variation, and of a corresponding lunar effect, was developed by Schuster and later by Chapman. All the problems of the theory have not been resolved but its essential correctness has received support in three ways which have led to its general acceptance : the experimental discovery of the ionosphere; characteristics of the magnetic effect which accompanies a large solar flare; and the discovery by a rocket ascent in 1949 of a discontinuity of the geomagnetic field at about 100 km due to the concentration of an electric current there.The atmospheric dynamo theory of the magnetic daily variations implies that any steady wind in the upper atmosphere must also be reflected in the magnetic records, and during the past ten years Wulf has examined this possibility, with limited success. Recently Vestine, proceeding on the assumption that all currents causing magnetic disturbances are located within the high atmosphere, has derived wind systems compatible with the annual variation of magnetic disturbance and with the features shown by a particular magnetic storm. Although the validity of Vestine's basic assumption is in considerable doubt, his contribution remains an important one and points the way to future progress. The prospect of obtaining actual measurements of the ionospheric winds by means of the newly developed radarsonde, combined with the regular ionospheric measurements now available, make it probable that important progress with this problem will be made in the next few years.
Noctilucent clouds
Authors: Paton J. 
Published: February 2007

AbstractBrilliant displays of the rare noctilucent clouds have recently been seen from central Scotland, and their height, position and speed have been determined from parallactic photographs. Observations of these clouds provide information concerning the physical state of the upper atmosphere at the height of about 80 km at which they invariably occur. Besides yielding direct measurements of wind, they indicate the existence of a temperature minimum at 80 km. Wind speeds of the order of 50 m/sec have been measured; Störmer has recorded speeds of more than 100 m/sec, and Jesse of about 300 m/sec. On every occasion when the clouds have been observed from Scotland, this movement has been from the east‐north‐east. But, since they are made visible by the sunlight scattered by the material of which they are composed, they are observed only on nights when the sun remains close below the horizon — that is, during the summer months in middle latitudes. Presumably they may be present at other times and in other latitudes, but they will not remain sunlit long enough to be observed. Their nature is still in doubt, though their tendency to appear at times of comet and meteor occurrences strongly supports the belief that they consist of meteoric dust. E. G. Bowen has recently pointed out that they appear either on or very near the dates of the daylight meteor streams discovered at Jodrell Bank, but Scottish observations show no such tendency. On one occasion, a portion of the clouds was observed to change colour from vivid blue to white, suggesting growth of the cloud particles by condensation. When opportunity offers, the new spectrograph at St. Andrews will be employed to investigate such changes in the spectrum. Finally, slides were shown illustrating a remarkably sudden change from their characteristically stable structure to quite chaotic shapes that occurred in the early morning of 25 July 1950. Noctilucent clouds have been observed on twenty‐two nights since 1939; but this was the only occasion when turbulence was seen. It may be significant that it was also the only occasion when aurora occurred simultaneously with the noctilucent clouds.
The frequency distribution of the annual maximum (or minimum) values of meteorological elements
Authors: Jenkinson A. F. 
Published: February 2007

AbstractIt is shown that the probability P that the annual maximum value of a meteorological element is less than a given value x can be expressed as exp
equation image
where a and k are constants such that ak is positive.The parameters a and k can be evaluated from data of annual maximum values for a given period of years. Hence we derive the average highest and lowest in sets of T annual maxima, and also the maximum value to be expected once in T years.
Theory of non‐horizontal adiabatic flow in the atmosphere
Authors: Scorer R. S. 
Published: February 2007

AbstractThe equation of continuity takes the formwhen there are appreciable vertical displacements (see Section 1 for list of symbols). The stream function, Φ, for two‐dimensional steady motion satisfies an equation which for vertical displacements of less than about a kilometre reduces to the formwhereG1andG2are functions of Φ determined by the profile of the air current entering the region under study. This is probably the best form for numerical solution.Bernoulli's equation shows that (gz+q2– τ) is constant along a streamline in steady adiabatic flow.The perturbation equations which have already been widely used are derived as a special case. Except in this case the solution for three‐dimensional flow is very much more difficult to obtain than that for two‐dimensional flow.The lateral stretching of vortex lines in flow over unlevel ground reduces or increases the surface wind according as the wind increases or decreases with height. This process may be used to explain the location of blow‐downs in forests on hillsides.The generation of shear in non‐horizontal motion can occur at already existing discontinuities of temperature (or velocity). If the motion is unstable so that turbulence is generated, other things being equal the more stable (statically) the temperature inversion the more likely it is to produce turbulence in mountain waves.
Short periods of unseasonal warmth or cold in daily mean maximum temperatures at Bidston
Authors: Reynolds G. 
Published: February 2007

AbstractDaily means of maximum temperature at Bidston over the 54 years 1900–53 have been examined and in them short periods of unseasonal warmth or cold have been found. Efforts to demonstrate the statistical significance of the anomalies met with difficulties which are outlined, but the results are tabulated and briefly compared with those of previous workers in this field.
Medium‐scale turbulence in the trade winds
Authors: Charnock H. , Francis J. R. D. , Sheppard P. A. 
Published: February 2007

AbstractDouble‐theodolite observations of pilot balloons were made in trade‐wind air at Anegada (18°45′N, 64°20′W), a small, low‐lying island in the British Virgin Islands, in Spring 1953. Ascents were made at 5 to 15 min intervals over working days of 7 to 8 hr duration on 15 days extending over a total period of 27 days. They provided values of the component air velocities u, v, w, in orthogonal co‐ordinate directions x, y, z respectively (x, y axes fixed in horizontal plane, z vertical), over 50 m intervals of height (20‐sec intervals of time) up to about 1·5 km.Fluctuations in the motion at heights up to 1·5 km and of time‐scale varying from about a minute to several days are analysed and discussed. The work is a pioneer study over most of this spectrum and has the special interest of dealing with a field of flow in which the directions of the mean surface wind and the thermal wind are opposed (there was a maximum in the profile of mean wind speed at a height of a few hundred metres) and in which cumulus convection is almost always present.Fluctuations from the mean flow were analysed using averaging periods increasing from about 3 hr up to the whole 27‐day period. For none of these averaging periods was there equipartition of eddying energy in the three velocity components; w′2 was one to two orders of magnitude lower than u′2 and v′2, the difference being greater the longer the averaging period.The covariances u′v′, u′w′, v′w′ were also evaluated for motions at various heights and for the various averaging periods. u′v′ increased with averaging period and changed sign with height: it appeared that horizontal momentum was being transferred to the north by the larger‐scale motions, a smaller amount being transferred to the south by smaller‐scale motions. u′w′ and v′w′ were in general less than u′v′ and generally varied less systematically with averaging period. Values computed from the smaller components of the motion sampled were in fair agreement with shearing stresses computed by the method of geostrophic departure (using profiles of mean wind and the observed pressure field). The direction of the resultant of u′w′ and v′w′ agreed surprisingly closely with the direction of the vertical shear vector of the mean wind velocity, the implied coefficient of eddy viscosity for the spectral range sampled being about 105 cm2 sec−1 over the whole range of height.
The relation between standard deviation of contour height and standard vector deviation of wind
Authors: Jenkinson A. F. 
Published: February 2007

AbstractA formula is derived, believed to be valid for all places outside the tropics and at all levels between the top of the friction layer and about 300 mb, expressing standard vector deviation of wind as a constant multiplied by the product of the standard deviation of contour height and the cosecant of latitude.The formula may be written σ = 0.064 s cosec where a is the standard vector deviation of wind in kt, s is the standard deviation of contour height in ft and ϕ is the latitude.A similar relationship is derived for levels between 300 mb and 100 mb. We may write σ = κw cosec ϕ where κ has the same value at all places but decreases uniformly with height from 0.064 at 300 mb to 0.033 at 100 mb.World seasonal maps of the standard vector deviation of wind immediately above the friction layer have been prepared from corresponding maps of the standard deviation of surface pressure; and seasonal maps of standard vector deviation of wind at 500 mb over part of the North Atlantic were prepared from maps of standard deviation of contour height computed directly from daily values.