bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of the 15μ carbon‐dioxide band on the atmospheric infra‐red cooling rate
Authors: Plass G. N. 
Published: February 2007

AbstractThe upward and downward radiation flux and cooling rate are calculated for the 15μ band of carbon dioxide. Results are obtained for three different carbon‐dioxide concentrations from the surface of the earth to 75 km, and for six frequency intervals covering the band. The infra‐red absorption measurements of Cloud (1952) are used for calculations, on a high‐speed electronic computer, by a method which takes account of the pressure and Doppler broadening, the overlapping of the spectral lines, and the variation of the intensity and half‐width of the spectral lines with temperature and pressure. The numerical integration is performed over intervals that are never larger than 1 km and average values over layers are not used. The cooling rate for the present atmospheric carbon‐dioxide concentration is greater than 1°C/day from 24 km to 70 km and is greater than 4°C/day from 38 km to 55 km. The sum of the ozone and carbon‐dioxide cooling rates is greater than 4°C/day from 33 km to 57 km and agrees reasonably well with the heating due to ozone absorption. The results for different carbon‐dioxide concentrations indicate that the average temperature at the surface of the earth would rise by 3.6°C if the carbon‐dioxide concentration were doubled and would fall by 3.8°C if the carbon‐dioxide concentration were halved, on the assumption that nothing else changed to affect the radiation balance.
An inherent precipitation mechanism in cumulus clouds
Authors: East T. W. R. 
Published: February 2007

AbstractIn a fair‐weather cumulus, the largest droplets, which are of 18 microns radius, grow too slowly by differential settling to become precipitation (although the time to reach raindrop size from 50 μ, for instance, would be comparatively short). Even at 18 μ their terminal speed is sufficient for growth, were it not that most of the droplets they encounter are small enough to avoid capture. Using Langmuir's collision efficiencies, the calculated time to grow from 18 to 50 μ radius is 2 hr. This time would be reduced to 12 min if the cloud sample had first ascended until there were 4 g of condensed water per kg of air, as must take place in the updraught of a cumulus congestus.Condensation and coalescence actually occur simultaneously and the first 50 μ droplets appear at about the 6 g/kg level; this is about the level at which the first radar echo should, and does, appear. The apparent descent of the echo can be accounted for by droplet growth at lower levels. The rapid development of precipitation in cumulus can be explained thus without invoking giant nuclei or ice.The intensity required for turbulence to be a potent coalescing agency was found to be greater by a factor ten than the intensity of turbulence deduced from aircraft measurements.
A synoptic study of west african disturbance lines
Authors: Eldridge R. H. 
Published: February 2007

AbstractThe paper gives an account of Disturbance Lines (D/Ls) observed on the charts of the forecasting office of the Ghana Meteorological Department at Accra in 1955. The progress of one of the larger D/Ls is shown to indicate the extensive area affected in some cases. The origins of D/Ls, their movement, distribution, and other characteristics, are described. The importance of the phenomenon in the local weather is shown by the proportion of the monthly rainfall due to D/Ls at four Ghana stations. Emphasis is placed on the nature of the D/L as a disturbance which moves through the atmosphere, transferring convective energy to other forms, notably horizontal kinetic energy, in an ordered manner.
Attenuation of swell in the north atlantic ocean
Authors: Darbyshire J. 
Published: February 2007

AbstractWaves recorded in the decay area by a ship‐borne wave recorder on o.w.s. Weather Explorer are compared with estimates of waves in the generating area. By restricting attention to the wave energy contained within one‐second wave period intervals, it is possible to eliminate the effect of dispersion and to study the decrease in height due to loss of wave energy and the broadening of the wave front. While it is not possible to give an accurate assessment of the relative magnitude of these effects, the formula obtained in the case of calm conditions or following winds in the decay area is HT/H = (300/R)1/2, where R is the distance of the recording point from the centre of the generating area. This formula does not depend on wave period and following wind speed, and suggests that the effect of broadening the wave front is the more important. It has been used successfully in predicting wave heights and periods at Casablanca.
The absorption coefficient of ozone at 3021 å
Authors: Hearn A. G. , Walshaw C. D. , Wormell T. W. 
Published: February 2007

AbstractA new determination of the absolute value of the absorption coefficient of ozone at 3021 Å is described. The value obtained for the decimal absorption coefficient, measured at 20°C, is 3.310 ± 0.009 (cm STP)−1. This figure is in excellent agreement with the value for this wavelength obtained by Vigroux (1953) and may be used with confidence in meteorological applications.
Some measurements on undercutting cold air
Authors: Berson F. A. 
Published: February 2007

AbstractFrom time series of closely‐spaced upper‐wind (pilot‐balloon) measurements in the rear of synoptic lines of wind shift and cooling, the configuration of the elevated wind‐shear layer and the strength of the flow beneath are deduced. The height of the shear layer does not rise uniformly with time, but at one stage remains constant or decreases, before resuming a sustained rise. It is demonstrated by the method of dynamic similarity that this phenomenon is broadly the counterpart of the friction head on density surges in stratified liquids.Cumulative inflow into the advancing wedge of cold air is compared with the total mass in the cold air wedge and found to be generally in excess of this, the exceptions occurring with sea‐breezes or analogous phenomena on a larger scale (coastal fronts). In one case where sufficient observations are available, vertical velocities are computed. The excess inflow is shown to be associated with a vertical circulation involving considerable mass transfer upward across the shear zone.
Sources and sinks of radiative energy from 30 to 90 km
Authors: Murgatroyd R. J. , Goody R. M. 
Published: February 2007

AbstractThe absorption of solar radiation and the exchange of long‐wave terrestrial radiation are computed for the 30 to 90 km region for all latitudes using the climatological mean temperatures given by Murgatroyd (1957). Over most of the earth's surface (approximately 30° in the winter hemisphere to 60° in the summer hemisphere) there is a close approach to radiative equilibrium at all the levels considered. In the polar regions, however, there is a significant departure from radiative equilibrium with excess heating during the summer and excess cooling during the winter.
Ice‐nucleating properties of some natural mineral dusts
Authors: Mason B. J. , Maybank J. 
Published: February 2007

AbstractA fairly wide range of 28 naturally‐occurring mineral dusts has been tested for ability to act as ice nuclei. 19 substances, mainly silicate minerals of the clay and mica groups, are found to be effective at −18°C; seven of these are active above −10°C. The most abundant of these is kaolinite with a threshold temperature of −9°C. 10 of the 28 substances, again mainly silicates, are found to become more efficient ice nuclei having once been involved in ice‐crystal formation, i.e. they can be pre‐activated. Thus, ice crystals grown on kaolinite nuclei, which are initially active at −9°C, when evaporated and warmed to near 0°C in a dry atmosphere, leave behind nuclei which are thereafter effective at −4°C. Particles of montmorillonite, another important constituent of some clays and initially inactive even at −25°C, may be pre‐activated to serve as ice nuclei at temperatures as high as −10°C.It is suggested that although such particles can initially form ice crystals only at cirrus levels, when the ice crystals evaporate they may leave behind some ‘trained’ nuclei which may later seed lower clouds at temperatures only a few degrees below 0°C. On this hypothesis, the fact that efficient nuclei are occasionally more abundant at higher levels would not necessarily imply that they originate from outer space; indeed, in view of the poor nucleating properties of some meteoritic material that was tested, it appears that atmospheric ice nuclei are predominantly of terrestrial origin, with the clay minerals, particularly kaolinite, a major source.
Modification of the structure of a tropical cyclone on traversing a high plateau
Authors: Sellick N. P. 
Published: February 2007

AbstractApparent continuity is established between an Indian Ocean cyclone which reached the coast of southern Africa and a disturbance which traversed the continent from east to west. The surface structure of the disturbance is established from autographic records of its passage over the Rhodesias and Nyasaland. The pressure field is fitted to the ‘normal’ vortex of James (1950) and the upper winds observed are in fair accord. The surface observations indicate the presence of broad belts of northwest and southeast winds with a fairly abrupt transition but there is no evidence of fronts. Precipitation of the order of 50 mm per day is recorded over wide areas on several successive days. From consideration of the observed moisture content of the atmosphere it is inferred that an inflow of the order of 2 m/sec in the lowest layers is required to account for the precipitation. Elementary dynamic theory requires that such an inflow be accompanied by increasing circulation and deepening of the system. The depression, however, weakened and filled up slowly and it is shown that a reasonable allowance for turbulent and frictional losses would account for this.
The relation between Eulerian time and space spectra
Authors: Panofsky H. A. , Cramer H. E. , Rao V. R. K. 
Published: February 2007

AbstractSimultaneous observations of space correlations and time correlations verify that Taylor's hypothesis x = Ut is valid for intervals up to at least 90 m, and for relative intensities of turbulence at least up to 0·26. It is also shown that, when the stratification is stable, the longitudinal scale of turbulence tends to be much larger along the flow than across it. In an unstable layer, the scale is of the same order of magnitude in all directions.
Atmospheric pollution by hydrochloric acid
Authors: Gorham Eville 
Published: February 2007

AbstractPrecipitation samples from urban deposit gauges in Britain exhibit a distinct positive correlation between chloride and acidity in samples of pH < 5·7. The first‐order correlation coefficients for hydrogen ions and chloride in deposits from Sheffield, and from Manchester and Salford, are shown to be highly significant, while those for hydrogen ions and sulphate are not significant. It is therefore suggested that hydrochloric acid should be considered in assessing the causes of rain acidity in urban areas.
The meteorology of North Greenland during the midwinter period
Authors: Hamilton R. A. 
Published: February 2007

AbstractDuring the midwinter months the general airflow over N. Greenland is southwesterly, but near the surface of the ice sheet, which is cooled by radiation in the polar night, katabatic winds flow from the higher parts of the ice sheet towards the coast. At sheltered places on or near the coast pools of cold stagnant air collect in fine weather when the pressure gradient is weak.Analysis of the 700 mb charts for two midwinter seasons shows that breaks in the predominantly fine weather were caused by depressions and their associated fronts which crossed the inland ice. There were about 15 disturbances per month which affected N. Greenland, but only a few of these caused precipitation. Most of the fronts were weak and the snowfall slight. During the first period of two midwinter months under consideration the only considerable fall of snow occurred when a deep depression remained almost stationary over S. Greenland for three days and drew moist air from the N. Atlantic over N. Greenland. The onset of the strong northwesterly wind on the coast after a period of calm is generally associated with the passage of a cold front.There is normally an inversion in the lowest layers above the ice sheet and the air temperature on the inland ice varies with the wind speed and the air mass. It is estimated that the temperature difference between the bottom and top of the inversion varies from around 0°C in overcast conditions with a strong wind to around 25°C in clear and calm conditions. Warm air is sometimes carried in the southwesterly circulation over the inland ice : the highest temperature measured on the ice sheet in the midwinter months was −18°C in a warm sector, and the lowest was −66°C in fine and almost calm weather. On the coast the onset of the northwesterly wind is marked by a sudden rise of temperature and fall of humidity : when the wind falls to calm the temperature falls rapidly at first, but within 24 hours reaches a value from which it differs little during the period of several days before the next onset of the northwesterly wind.There is a fairly close relationship between the height and intensity of drift snow, the wind speed and the visibility. Snow does not begin to drift until the wind speed reaches 10 kt; the snow drift is moderate with a visibility of about 2 km when the wind speed is 17 kt and is heavy with a visibility of about 200 m when the wind speed is 27 kt. After a spell of fine weather over N. Greenland drift snow was absent on the inland ice even with a wind speed of 21 kt. Drift snow was observed in the coastal area only after a fall of snow.A comparison of the mean pressures and precipitation totals for the midwinter months under review with mean charts and mean monthly precipitation totals for other stations in the area for different years suggests that the two Januarys studied were normal months, but the two Decembers were abnormal.
Stratospheric temperatures over the Antarctic
Authors: Bannon J. K. 
Published: February 2007

AbstractSome recent observations together with data from earlier expeditions (Court 1942, Schumacher 1955 and others) suggest that the annual variation of temperature in the stratosphere over the Antarctic is characteristically asymmetric with a steep rise of temperature in the spring. This is probably not general over the Arctic. The tropopause over the Antarctic is significantly higher than over the Arctic in their respective winters and the variability of temperature in the lower stratosphere appears to be considerably less in the same season over the Antarctic than over the Arctic.
On the influence of thickness and temperature on the ‘cut‐off’ characteristics of glass filters
Authors: Ångström A. K. , Drummond A. J. 
Published: February 2007

AbstractSchott glass filters OG1, RG2 and RG8 are investigated with respect to the dependence of the lower sharp wavelength ‘cut‐off’ on filter thickness and temperature. Typical values of the main cut‐off characteristics are presented conveniently in tabular form.
The spectrum of vertical velocity near the surface
Authors: Panofsky H. A. , McCormick R. A. 
Published: February 2007

AbstractObservations of a considerable number of vertical‐velocity spectra are combined to show that under near‐neutral and unstable conditions, the shape of the spectrum is essentially invariant up to heights of order 100 m, and the ‘scale’ of turbulence is proportional to height within this régime.A semi‐empirical working hypothesis is suggested which relates the spectrum to wind speed, lapse rate, height and roughness.
The vertical distribution of atmospheric ozone over Canadian stations from umkehr observations
Authors: Mateer C. L. , Godson W. L. 
Published: February 2007

AbstractThe vertical distribution of ozone is estimated from umkehr observations at the Canadian ozone stations at Edmonton, Moosonee and Resolute. Average seasonal vertical distributions are presented and compared with European and Indian results. The Canadian results indicate the existence of two levels of maximum ozone density, one at about 27 km and a lower one at about 15 km. During the spring, summer and autumn seasons the higher‐level maximum is slightly more predominant than the lower. However, during the winter months, the lower‐level maximum becomes much more pronounced. As a result, there is an extremely good correlation between ozone amount between 12 and 24 km and total ozone, three‐quarters of the seasonal changes in total ozone being attributable to changes in this layer.
Thermal structure in the lower layers of anticyclones
Authors: Findlater J. 
Published: February 2007

AbstractThe amount of stratocumulus cloud in easterly anticyclonic airstreams over the British Isles is shown to be related to the pressure and temperature at the base of anticyclonic inversions. These two parameters are not conservative. Fluctuations occur, often in a periodic manner, as shallow but distinct cold and warm areas circulate in the lower layers of anticyclones. These cold and warm areas originate from successive pulses of cold and warm air on the flanks of anticyclones but retain their identity after the fronts separating them have decayed and been omitted from routine analyses. Approximate dimensions and forms of significant temperature patterns are deduced.
Large‐amplitude periodic lee waves in stratified fluids Pt. (1) – Non‐linear solution
Authors: Sen‐Gupta B. K. 
Published: February 2007

AbstractThis paper deals with a two‐dimensional train of free, internal gravity standing waves in an inviscid, incompressible, stably‐stratified fluid bounded by a rigid base and free surface. The waves are similar to those studied by R. R. Long, and are assumed to be periodic in the horizontal direction, and independent of time. The classical linearized theory has been extended by examining the wave equation with a variableL02parameter. The equation has been solved numerically, and the method of approach has been to regard the non‐linear terms as ‘perturbations’ on the main wave term which is treated in the classical linearized theory. Deviations from the linearized theory are shown to become more pronounced the larger the amplitude of the wave, as the streamlines become displaced by presence of the non‐linear terms, and the relative magnitudes of non‐linear coefficients are compared with the main terms for the cases computed. The undisturbed fluid stream is the same for all the computed wave profiles, and the amplitude has been varied from small to large to show the development of rotor regions.
Aircraft observations of the horizontal distribution of chloride particles and their relation to drop‐growth processes in clouds
Authors: Singleton F. , Durbin W. G. 
Published: February 2007

AbstractSeven flights have been made measuring horizontal variations of chloride particles (masses > 10−13 g) in the neighbourhood of the British Isles. From these it is concluded that concentrations can vary from about 1,500 l−1 in unstable north‐westerly airstreams to 300 l−1 in anticyclonic air over the U.K., and 50 l−1 over the Continent in air of continental origin. Some evidence is found that concentrations can increase near windward coasts, and can, on occasion, increase with height in the lower levels of the atmosphere.From a theoretical examination of the droplet spectra at cloud base which, on certain plausible assumptions, would result from the observed chloride particle distributions, it is concluded that these nucleus concentrations could account for the large (> 100 μ diameter) drops commonly found in cumulus and layer clouds over the United Kingdom.
Large‐amplitude periodic lee waves in stratified fluids Pt. II – Linear solution
Authors: Sen‐Gupta B. K. 
Published: February 2007

AbstractBy means of a transformation originally proposed by Long (1953) we obtain exact solutions for periodic wave flow of a stratified shearing fluid between rigid plane boundaries. The examples worked out are less particular than any previously published, and show a substantial decrease in wavelength when the amplitude increases once rotors have been formed even though the equations are linear.
Radiative temperature in the heat balance of natural surfaces
Authors: Monteith J. L. , Szeicz G. 
Published: February 2007

AbstractA Linke‐Feussner radiometer was used to measure the radiative temperature of natural surfaces, with small errors caused by the divergence of radiative flux and by its angular variation. On typical cloudless summer days, the maximum temperature of tall crops and of open water was close to maximum air temperature; a bare soil surface exceeded air temperature by 20°C; short grass was the coldest surface at night. A linear variation of net (total) radiation with net short‐wave radiation was established for several tall crops, and the increase in long‐wave loss per unit increase of net radiation (heating coefficient) was 0·08. Daily totals of net radiation as a percentage of solar radiation income were: 37 per cent (bare soil), 41 per cent (short grass), 46 per cent (tall crop), and 53 per cent (water).When the aerodynamic character of a crop is known, the effective resistance of the stomata to water‐vapour diffusion can be related theoretically to the difference between surface and air temperature. For rough vegetation, estimated stomatal resistance is 0·4 to 0·8 sec cm−1 and the estimated heating coefficient is almost independent of wind speed at about 0·1.
Gusts over hills (in relation to wind‐power utilization)
Authors: Frenkiel J. 
Published: February 2007

AbstractMeasurements of gusts over the peaks of two hills are described, and results in the form of gust variation with height and gust amplitudes are tabulated. The difference in the ratio of gust variation with height to mean velocity variation with height for the two hills may be linked with differences in the wind ratio/temperature gradient curve.
Ozone distribution and the continuum from observations in the region of the 1,043 cm−1 band
Authors: Dave J. V. , Sheppard P. A. , Walshaw C. D. 
Published: February 2007

AbstractAn extended series of high‐resolution observations of atmospheric emission at five frequencies in the region of the 1,043 cm−1 ozone band has been made in order to infer the vertical distribution of ozone and the behaviour of the atmospheric continuum. The latter is found to vary from day to day and seasonally, probably because of changes in the nature, amount or vertical distribution of aerosol. This variability makes it difficult to exploit, in moist, hazy atmospheres, the inherent potential of the variation of line intensity across the ozone band in the derivation of the vertical distribution of ozone. The ozone contents of three layers, surface‐600 mb, 600–300 mb, 300–100 mb are obtained from the emission at 1,053·2 cm−1 only; they are found to be generally high, probably because the ozone transmission function used was not matched to the resolution of the observations. Relative variations in the lowest layer are probably realistic.