bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seiches in lough neagh
Authors: Darbyshire J. , Darbyshire Mollie 
Published: February 2007

AbstractRecords of seiches in Lough Neagh during April 1949 were investigated. Fourier analysis of the records indicated three period bands centred round 1.6 hr, 1.15 hr, and 0.75 hr. The two longer periods appeared to have a nodal line across the centre of the lake, parallel to the shorter sides. Methods of deriving these periods in terms of the shape of the lake basin are discussed.The amplitudes of the seiches were compared with the wind records and a high degree of correlation was obtained between the amplitude and Wdθ/dt, where W is the wind speed and dθ/dt is the rate of change of wind direction.An estimate was made of the coefficient of damping of the seiche amplitude and it was found to correspond to a decay to half value in 10 hr.
Intracloud lightning discharges
Authors: Smith L. G. 
Published: February 2007

AbstractSlow electric‐field changes produced by lightning discharges within clouds have been recorded simultaneously at two stations 13.2 km apart. It is found that the same cloud discharge may give field changes of different types (simple and complex), or of opposite sign (reversal effect), or both, at the two stations. Two main types of complex slow field change are described. The interpretation of slow field changes is discussed in terms of movement of charge. It is shown that, in the most frequent case, the cloud discharge involves the raising of negative charge.
The intensity of turbulence in convective clouds
Authors: East T. W. R. 
Published: February 2007

AbstractCalculations of collision rates between cloud droplets in turbulent air show that this would be an effective precipitation mechanism in cumulus if the r.m.s. turbulent acceleration were about 3 times that due to gravity. An estimated value, based on published records of flights through thunderstorms, is about one‐sixth of gravity. In the absence of more direct evidence, it seems that turbulence is not an important factor in convective precipitation.
A dynamical model for large‐scale tropospheric and stratospheric motions
Authors: Gates W. Lawrence 
Published: February 2007

AbstractA physical model of the atmosphere is postulated in which both the troposphere and stratosphere are characterized by a uniform thermal wind and a constant static stability, and are separated by a tropopause across which these quantities are discontinuous. Assuming the tropopause to be quasi‐isobaric, a simplified model for the mean velocity, temperature and vertical motion fields of both the troposphere and stratosphere, the velocity near the earth's surface, and both the horizontal and vertical motion at the tropopause is constructed. The model may be regarded alternatively as a four‐parameter or four‐level model, but it is felt to avoid the primary disadvantages of the exclusive use of either the parameterized or layered formulation. Analysis of the special case of an equivalent‐barotropic stratosphere indicates the existence of systematic tropopause variations, with the vertical motion at this level generally in phase with that of the mid‐troposphere, and with a system of opposing vertical motion higher in the stratosphere. These features are in general agreement with the results of observational and synoptic research, although the details of the role of the tropopause must await further calculations. The analysis of the stability of tropospheric perturbations in a baroclinic zonal current shows a stabilizing influence of the stratosphere on the initial amplification of the disturbances. The minimum vertical shears required for instability with a basic jet current of 40 m sec−1 are more than twice those required without a stratosphere, and are shown to lie between the mean summer and winter shears in the zone of maximum westerlies.
Air motion over a heated land mass: II
Authors: Smith R. C. 
Published: February 2007

AbstractIn a previous paper (Smith 1955), the problem of the resultant theoretical velocity field that arises from the diurnal variation of heating of a land mass with an initially stationary air mass was considered. The present paper considers the same problem with an initial overall velocity. Henceforth the first paper (Smith 1955) will be referred to as Part I.The same heat function is used as in Part I for the time and horizontal variations, but the vertical variation is amended for closer approximation to the different circumstances. The difficulty of the boundary condition at infinite height is overcome by associating the solutions with those of Pt. I.The resulting surface temperatures and vertical velocities at different times are shown in tables and graphs.
The thermodynamics of saturated air: A contribution to the classical theory
Authors: Saunders P. M. 
Published: February 2007

AbstractThe temperature attained in the reversible and pseudo‐adiabatic expansion of air saturated with respect to liquid water is taken as a reference; the temperatures attained in the following expansions from the same initial state are then compared with it: (a) the ice‐saturation pseudo‐adiabatic process (b) the water‐saturation adiabatic process (c) the ice‐saturation adiabatic process.The results of these comparisons are summarized in Figs. 1 to 5 of this paper.Similarly, the cloud virtual temperature, the virtual temperature adjusted for the weight of suspended particles, attained in water‐saturation adiabatic expansion, is compared with that attained in water‐saturation pseudo‐adiabatic expansion; Fig. 6.The implications of these calculations for the properties and behaviour of cumulus are commented upon.
Ozone information from sky observations
Authors: Walton G. F. 
Published: February 2007

AbstractThe information of the vertical distribution of atmospheric ozone obtainable from measurements of scattered sunlight received from various directions in the sky is considered. It is shown that observations in a particular direction in the sky could replace, but would not supplement the customary zenith sky observations, except in high latitudes at certain seasons of the year. Observations in various directions in the sky would be equivalent to zenith sky observations made throughout the day.
The meteorology of North Greenland during the midsummer period
Authors: Hamilton R. A. 
Published: February 2007

AbstractAn elevated ice sheet of the size of Greenland has a strong influence on its own weather. On account of the cooling by radiation of the snow surface and of the lower layers of the air there is a tendency for a system of low‐level outflowing katabatic winds to be set up. The weather is also influenced by the cyclonic systems characteristic of middle latitudes and their associated fronts.Northern Greenland is far from the main track of Atlantic depressions, and as the inland ice is here at its widest, conditions appear suitable for the establishment of the glacial anticyclone which would be expected to be disturbed only rarely by cyclonic systems. In order to study the frequency of these disturbances, and the normal meteorological conditions in the undisturbed periods, an investigation has been made of the weather in the area during the six midsummer weeks of 1953, in particular of the observations made at “Northice”“Northice” i not an accepted place name but in used in this paper for convenience.
near the crest of the ridge of the inland ice and at Britannia Sø near the east coast.Owing to the elevation of the ice sheet mean sea‐level synoptic charts cannot be used satisfactorily, and a method of drawing 700 mb charts and using the same techniques as are used in temperate regions for analysis of mean sea‐level charts has been developed. As the weather is predominantly fine all occurrences of appreciable cloudiness, precipitation and abnormal surface wind are significant and in almost all cases were due to cyclonic disturbances and their associated fronts which could be followed on the series of 700 mb charts. A total of 16 depressions or waves caused 19 disturbances (in three cases the effects of the warm and cold fronts were clearly separated) at either one or both of the two stations, but only 5 of these caused precipitation exceeding 1·0 mm at either station.During the anticyclonic period of 11 days when the 700 mb wind was light and variable the weather at Northice was fine with a katabatic surface wind of 280° 13 kt. The diurnal range of temperature at Northice was 6·8°C but only 3·7°C at Britannia Sø. The diurnal variation of relative humidity was small. The upper winds at Northice were mainly S to W at low levels and S to E at 16 km.A comparison of June 1953 with June 1954, and with statistics for other Greenland stations in other years, indicates that the midsummer of 1953 can probably be regarded as representative of a normal midsummer.
Temperature, humidity and cloud near fronts in the middle and upper troposphere
Authors: Sawyer J. S. 
Published: February 2007

AbstractExploratory flights through fronts beneath the jet stream confirm that a narrow frontal zone some 30 to 50 mi wide with sharp boundaries is often present at the 500 mb level. On other occasions the temperature changes are more diffuse. The air in and near the frontal zone is usually very dry and must have undergone subsidence.Dynamic considerations suggest that the very strong temperature gradient of the frontal zone at 500 mb arises from the differential subsidence of air on the cold side of the jet stream which leads to a tilting of the isentropic surfaces.
A synoptic study of day‐to‐day changes of ozone over the British Isles
Authors: Martin D. W. , Brewer A. W. 
Published: February 2007

AbstractTwo months of European ozone data are analysed in relation to 24‐hr trajectories determined from 100 mb contour charts. Significant correlations are obtained between vertical movements at 100 mb and non‐advective and local changes of ozone, 100 mb temperature and 100 mb vorticity. These confirm the importance of horizontal convergence as a dynamic effect in the lower stratosphere.Further correlations are presented between these changes and the accompanying N‐S displacements in an attempt to relate short‐period phenomena and the observed global distribution of ozone. The results do not conform to the simple models of the atmosphere considered here.
Point‐discharge currents from natural and artificial points
Authors: Maund J. E. , Chalmers J. Alan 
Published: February 2007

AbstractWhen point discharge occurs at an earth‐connected point, ions of one sign travel to earth through the point while ions of opposite sign travel away in the wind. This stream of ions reduces the potential gradient at the ground to leeward of the point below that to windward. Theory shows that, under suitable conditions, this difference in potential gradient is close to that predicted for a line of charge, even though the line is spread into a cone by turbulent diffusion. Measurements with point discharge from a 34 m mast show good agreement with theory, and this makes it possible to use the difference of potential gradient to determine the point‐discharge current through a tree. When applied to a line of trees, seasonal differences are found suggesting smaller currents from trees in leaf than from bare trees. Measurements with a 12 m sycamore tree in full leaf show no point‐discharge current even in potential gradients up to 7,000 v/m.
Interhemispherical features of the general circulation of the atmosphere
Authors: Rao Y. P. 
Published: February 2007

AbstractMean meridional wind components in the troposphere are computed at five stations along the Equator. Their significance is discussed in regard to mass exchange between the hemispheres. The eddy transport of heat across the Equator is found to be negligible. The possibility of seasonal exchange of heat between the hemispheres through meridional circulation across the Equator is discussed.
The statistical variation of wind with distance
Authors: Durst C. S. 
Published: February 2007

AbstractCorrelation coefficients have been formed between the winds at pairs of points, the correlation being made between components along the line joining the points and also between components at right‐angles. The original purpose was the derivation of the effective winds experienced by aircraft. However, certain results are found which appear to throw light on the application of turbulence theory to the large‐scale pattern of winds and hence it is thought that the results may be of more general interest.
A note on the synoptic climatology of Labrador‐Ungava
Authors: Barry R. G. 
Published: February 2007

AbstractAspects of the synoptic climatology of the Labrador‐Ungava peninsula are investigated with reference to a classification of airflow pattern types, formulated on the basis of synoptic weather maps for November 1956 to February 1958. The winters 1956–57 and 1957–58 exhibit, respectively, marked negative and positive temperature departures and the temperature and precipitation characteristics of the airflow types are discussed for these two seasons. The validity of the airflow categories is statistically tested.
Wind, temperature and humidity distribution at some cold fronts over SE. England
Authors: Miles M. K. 
Published: February 2007

AbstractRecent evidence from frequent radar‐sonde soundings at Crawley (Sussex) has been studied along with earlier published evidence to establish that a marked fall in humidity occurs directly above the front in a more or less random sample of cold fronts crossing southern England. This usually happens at levels above 700 mb and without a corresponding fall of temperature or any considerable change in wind direction at these levels.Evidence from trajectories shows that the dry warm air is drawn from a cold source and warmed dynamically before it enters the frontal zone. At this stage it is usually moving faster than, and in the same direction, as the warm moist air and this contributes to the formation of a marked humidity gradient at the junction of the two air masses.The air may sometimes be ascending at this junction, but there is no clear evidence that a wedge of cold air (where it exists) has anything to do with the vertical motion.
The structure of the arctic winter stratosphere over a 10‐yr period
Authors: Wilson Cynthia V. , Godson W. L. 
Published: February 2007

AbstractA series of 100‐mb temperature maps was drawn up for the winters 1949‐1950 to 1958‐1959 using 10‐day mean data. These maps were used to summarize the large‐scale events of each winter and of the ten winters in general. The results suggest the existence of two major patterns, both highly persistent.(i) An asymmetric pattern with a warm ridge over east Siberia‐Alaska and an elliptical cold‐core vortex over Eurasia.(ii) An eccentric bi‐polar distribution, the trough line extending from central Canada to central Siberia.The Aleutian ridge and Eurasian trough are quasi‐stationary features, common to both regimes, while the Canadian and North Atlantic sectors experience the greatest change from one regime to the other ‐ alternating warm ridge and cold trough. Both the regional climatology of the arctic winter stratosphere and the variations in the sequence of events from year to year for the Arctic as a whole, are described in terms of these two features and two alternating patterns.The striking asymmetry of both patterns in the stable stratosphere appears to require an external forcing agent, and this analysis tends to highlight the role of tropospheric activity.
Absorption in the stratosphere by some water‐vapour lines in the v2 band
Authors: Houghton J. T. 
Published: February 2007

AbstractA study has been made of some lines in the solar spectrum, as observed from an aircraft, due to absorption by atmospheric H2O16 and H2O18. The integrated absorptances for these lines, calculated using theoretical line strengths and various water‐vapour distributions, are compared with observed values. The water‐vapour distribution which gives the best fit is one which is very dry (mixing ratio 1·5 × 10−6) in the lower stratosphere, but considerably wetter (up to 5 × 10−5) above 25 mb.
The space‐filtering of monthly surface temperature anomaly data in terms of pattern, using empirical orthogonal functions
Authors: Grimmer M. 
Published: February 2007

AbstractIn statistical long‐range forecasting the large volume of data makes some form of filtering imperative both to reduce the data‐handling problem and to exclude random elements which do not contribute to understanding or prediction. In this study, which is an exercise in the statistical technique of factor analysis, fields of 30‐day surface temperature anomaly for the years 1881–1960 are filtered in terms of sets of patterns specific to each calendar month. These are derived empirically, and so truly reflect the characteristics of the original fields. In the resulting representation, the volume of data may be reduced to one quarter while retaining 80 per cent of the original variance, and a study of seasonal variation shows that continentality and zonal thermal advection are at all times of year the most important factors in shaping the 30‐day anomaly fields.
Polynomial approximations to radiative functions
Authors: Rodgers C. D. , Walshaw C. D. 
Published: February 2007

AbstractThe following polynomial approximations to functions often needed in radiative transfer calculations were derived by standard Chebyschev methods after an initial transformation of the independent variable. They form a convenient method of computing these functions on an electronic computer, and were used by Dave, Sheppard and Walshaw (1963), with the exception of No. 1, which has been modified to cover the whole range of the variable.
An analysis of the fluctuations in the tropical stratospheric wind
Authors: Probert‐Jones J. R. 
Published: February 2007

AbstractNumerical analysis of the zonal component of the wind at levels in the lower stratosphere at three tropical stations has enabled the period, amplitude and phase of the so‐called biennial oscillation to be found. There are two preferred periods, 27 and 22 1/2 months; the amplitude increases upwards from zero at the tropopause and is still increasing at the 30‐mb level; while the phase propagates downwards at a rate of about 1/3 radian/km.An harmonic, whose period is exactly half the fundamental, is found whose phase propagates downwards at the same rate. From estimates of the time of arrival in the lower stratosphere of the 22 1/2‐month oscillation in the fundamental and harmonic, the level of origin can be put between 32 and 80 km. By assuming coincidence of the nodes before the westerly maximum of the fundamental and the harmonic at the level of origin, the three possible heights within these limits are found to be 43, 61 or 79 1/2 km.The oscillation and its harmonic can account for over 90 per cent of the total variance in the monthly mean equatorial zonal wind.
Heating rates due to ozone computed by the curtis‐godson approximation
Authors: Clark John , Hitschfeld Walter 
Published: February 2007

AbstractThe heating produced by atmospheric ozone is calculated with the use of the Curtis‐Godson approximation, and the results are compared with rigorous computations performed on the same data by Hitschfeld and Houghton (1961). Agreement is good near the top and bottom of the ozone layer, while at intermediate heights, where the heating rates are particularly important, the approximation is not so successful. This pattern is confirmed by the use of the strong‐ and weak‐line criteria of Plass (1960). Although the applicability of the Curtis‐Godson approximation is thus found to be limited, there can be no question as to its convenience, and a simple radiation diagram for ozone, which makes use of this approximation, is prepared.
Waves in stratified media ‐ pt. iii
Authors: Sen‐Gupta B. K. 
Published: February 2007

AbstractA previous paper (Sen‐Gupta 1962, Pt. II) dealt with exact solutions of lee‐wave terms in the most general case for large displacement waves in stratified media. the present paper deals with a case less general, but involving simpler solutions, which may have wide application if one of the constants of the general case is made zero. Formal solutions are also given for generalized solutions to equations exploited in the previous paper, and these may have application if flow near the disturbing influence is to be studied.
Dynamical aspects of the bi‐polar stratospheric circulation
Authors: Sawyer J. S. 
Published: February 2007

AbstractThe wind and temperature distributions in a ridge over Alaska and a trough over eastern America are examined during periods of steady circulation in the stratosphere with dominant wave‐number two. Comparison of vorticity near the ridge and trough suggests that flow at about 30 mb is approximately non‐divergent. the distribution of convergence and divergence at other levels is not simple, but as air passes from ridge to trough subsidence is probably dominant poleward of the wind maximum and ascent on the equatorward side. Changes in wind shear and wind speed are as important as changes in curvature in determining the vorticity changes.
The objective analysis of horizontal wind divergence fields
Authors: Eddy A. 
Published: February 2007

AbstractStatistical evidence is adduced to support the contention that significant patterns are discernible in fields of divergence values computed from the horizontal winds using the Bellamy triangle technique.An objective method is presented for determining:
the percentage of the variance of a given data field which is explainable using a statistical objective analysis technique on a specified observational network,
the principal wavelengths present in the data field,
statistically determined weight curves for the objective analysis of the field.
Space autocorrelation shows a 1,700 nautical mile wavelength to be dominant in the tropospheric divergence fields and the noise level to be about 10−5 sec−1. the case history of a developing storm is presented and the divergence patterns associated with various aspects of the development are shown to be in agreement with synoptic experience.