bluuebunny/crossref_metadata_2025_split huggingface dataset:
Jet stream and long waves in a steady rotating‐dishpan experiment: Structure of the circulation
Authors: Riehl Herbert , Fultz Dave 
Published: February 2007

AbstractThe three‐dimensional structure of the flow of water in a steady rotating three‐wave dishpan experiment is computed and compared with the atmosphere.At first the experiment and methods of comparison between dishpan and atmosphere are described. Then motion and vorticity at the top surface are shown; trajectories leading from equatorial to polar rim of the pan are found. Next the three‐dimensional temperature field is determined, and from this the geostrophic motion at all depths.The flow pattern resembles the basic features of the middle‐latitude atmosphere in a remarkable way. Mobile long waves in a jet stream near the top overlie cyclonic and anticyclonic vortices farther down. There is, however, neither the counterpart of tropopause nor stratosphere in the temperature field, indicating that these features are not necessary for development of the basic flow pattern. Further, the distribution of momentum sources and sinks differs from that of the atmosphere, as momentum is given off to the inner (and possibly to the outer) cylinder, while most of the bottom acts as source. This throws doubt on the importance of momentum balance considerations for explanation of the principal flow features.Vertical motions are calculated in the interior of the fluid with the adiabatic assumption. Values again compare well with those of the atmosphere as does the distribution of centres of ascent and descent relative to long waves and cyclones. A positive correlation between temperature and vertical motion exists along the jet axis, hence there is release of potential energy. If averaging is performed along the jet‐stream axis, one finds that the centre of ascent lies equatorward, and the centre of descent poleward of the axis. Ifzonalaveraging is performed, however, the centre of ascent appears north of the zonal wind maximum, and the centre of descent on its equatorward side. This calculation uncovers a weakness of zonal averaging as a tool in studying the general circulation.Absolute vorticity is calculated on constant temperature surfaces in the interior of the liquid. It is found that the theorem of conservation of absolute vorticity is nearly fulfilled in the jet‐stream layer with wave motion; in the lower layer with vortices, validity of the theorem of conservation of potential vorticity is indicated qualitatively. The regions of convergence and divergence, as inferred from the vorticity changes along the relative stream‐lines, agree qualitatively with the vertical motion distribution.
Objective analysis in numerical forecasting
Authors: Bushby F. H. , Huckle Vera M. 
Published: February 2007

AbstractThis paper describes an objective technique for analysing sets of upper‐air data. The analyses resulting from the application of this technique to four sets of data for the NE Atlantic and Europe were compared with those produced subjectively by an analyst, and no marked differences were apparent.Numerical forecasts for twenty‐four hours ahead based on both subjective and objective analyses were computed for these four situations and the results compared with the actual developments. Only slight differences were noticed between the forecasts based on the subjective analyses and those based on the objective analyses in three of the four situations, but in the fourth situation the numerical forecast based on the objective analysis was much the better.
Evidence of a mean meridional circulation in the atmosphere from surface wind observations
Authors: Tucker G. B. 
Published: February 2007

AbstractSurface‐wind observations in the Northern Hemisphere are analysed and fields of mean meridional and zonal motion obtained. From these, profiles of mean meridional motion as a function of latitude are deduced. The results are consistent with a direct meridional circulation in low latitudes and an indirect circulation in mid‐latitudes, both attaining speeds of 1 to 2 m/sec at the surface. This scheme is found to be consistent with a decrease of upward flux of westerly momentum with height (convergence) in the surface layers in low latitudes and a decrease of downward flux in mid‐latitudes.
A preliminary investigation of long waves at Newlyn
Authors: Darbyshire J. 
Published: February 2007

AbstractLong waves of period greater than 1/2 min are recorded at Newlyn, Cornwall. There are two predominant types; one with a period of approximately 12 min and another with a period of 30 to 40 min. This investigation deals only with the longer‐period type and is concerned with the eight instances during the period Mar. 1956 to Mar. 1957 where these longer waves exceeded 7 in. in amplitude.The occurrence of these waves appears to be associated with the passage of meteorological fronts and a reasonable correlation is found between the amplitude and the northward component of the frontal velocity whilst the duration of the wave activity appears to decrease as the easterly component of the frontal velocity increases.Various suggestions regarding the nature of these waves are considered. The evidence that they are edge waves is not very convincing and the most likely explanation appears to be that the waves are due to the oscillation of Mounts Bay as a whole, or of the north‐western part of it.
The determination of tropospheric ozone from infra‐red emission spectra
Authors: Goody R. M. , Roach W. T. 
Published: February 2007

AbstractThe emission spectrum of the sky has been measured on 127 occasions at Ascot in a period of 12 months in 1956 and 1957, and the observations have been interpreted in terms of the total amount of ozone between 1,000 and 300 mb. The ozone amount in this layer varies about a mean value of 13 × 10−3 cm STP and an individual determination is accurate to about ± 3 × 10−3 cm STP.The results suggest that fluctuations in the total ozone amount are controlled by different mechanisms in spring and the rest of the year, and that during this period advection may be the dominating effect. There is evidence that some of the tropospheric ozone has come from the upper stratosphere, but it also seems probable that much has been advected into these latitudes.Our results show very little relation to ground‐level chemical measurements made just after mid‐day. This disagreement might possibly be due to secondary sources of ozone near ground‐level.
The decay of the ice‐nucleating properties of silver iodide released from an aircraft
Authors: Smith E. J. , Heffernan K. J. , Thompson W. J. 
Published: February 2007

AbstractSilver‐iodide smoke was released from an aircraft, together with a tracer of zinc sulphide, and both aerosols were detected in another aircraft. About 2 × 1014 freezing nuclei were emitted per gram of silver iodide burnt. The number of effective nuclei decreased on exposure to the air in the daytime by a factor of 1,000 in two hours. At night there was no detectable decay.
An essay on low‐latitude wind analysis
Authors: Scott J. R. 
Published: February 2007

AbstractA method of wind analysis widely used in low latitudes is shown to be basically unsound, using the results of another method of analysis. It is shown that analogy may usefully be drawn between middle‐latitude and equatorial airflow. A suggestion for the use of pressure data near the equator and brief comments on well‐known types of wind analysis are made. The emphasis is on equatorial conditions.
Dust concentrations in the Harmattan
Authors: McKeown H. D. J. 
Published: February 2007

AbstractA method of counting the very fine dust particles of the Harmattan and of determining their approximate size range is described, and some of the counts obtained at Ibadan, Nigeria, during the 1955–56 season are presented. It is suggested that the large dust concentrations may have a blanketing effect on terrestrial radiation.
The role of water particles in the atmospheric transmission of infra‐red radiation
Authors: Deirmendjian D. 
Published: February 2007

AbstractThe attenuation of infra‐red radiation by scattering on atmospheric haze particles, in the form of water droplets, is discussed in some detail. The spectrum is divided into two regions, the near infra‐red to λ 2·25 μ, where the refractive index of water may be assumed constant and real, and the region 2·25 to 12μ, where the index is complex and varies with the wavelength. This paper is concerned with the first region. It is shown that certain haze models, involving a continuous drop‐size distribution and previously used in explaining the attenuation of visible wavelengths and the aureole around the sun, adequately explain the window transmission measured by Gebbie and co‐authors (1951) along a horizontal path. The observed optical thickness of the whole atmosphere with respect to near infra‐red sunlight is also explained by means of these models.The infra‐red attenuation spectrum appears as a logical extension of the visible one and represents the continuous background upon which gas line and wing absorptions must be superposed. The magnitude of the latter can thus be assessed with more confidence.
A theory of fronts in relation to surface stress
Authors: Ball F. K. 
Published: February 2007

AbstractSurface‐stress terms are introduced into the equations governing the motion of the cold air ahead of a warm front or behind a cold front. Solutions for the steady state indicate that a katafront inversion tends to become horizontal at increasing distances from the front whereas an anafront inversion may continue to slope upwards indefinitely. The depth of cold air will, when the upper flow is curved cyclonically, actually decrease with increasing distance from a cold katafront. It is also shown that the existence of a sharp surface warm front depends on the sudden breakdown of a trailing layer of cold air. The thickness of this layer increases with decrease in latitude and as a result, sharp warm fronts are unlikely to occur at low latitudes. The conclusions concerning cold fronts are in broad agreement with Sansom's (1951) observations.
Measurements of space charge in the lower atmosphere using double field mills
Authors: Smiddy M. , Chalmers J. Alan 
Published: February 2007

AbstractTwo double field mills (Smiddy and Chalmers 1958) have been used to study space charge in the lowest 5 m of the atmosphere.Results in fair weather show small values, often negative, which can be explained in terms of radioactivity of the ground. Comparison with results from filtration apparatus suggest that the latter may be in error when small ions are present in large numbers.Results in light or moderate rain show small space charges, but in heavy rain, negative space charges of the order of – 1,000 μμc m−3 are found, probably formed by splashing. In snowfall, there are charges of both signs of about ± 500 μμc m−3.
The performance of a Gunn‐Bellani radiation integrator
Authors: Monteith J. L. , Szeicz G. 
Published: February 2007

AbstractAn alcohol‐filled Gunn‐Bellani radiation integrator, exposed at Rothamsted from June to December 1958, gave weekly distillation totals that were a linear function of short‐wave radiation on a horizontal surface above a limit of 500 cal cm−2 week−1. Laboratory experiments with both alcohol‐ and water‐filled models reveal a threshold radiation intensity which can be estimated from the properties of the distilling fluid and the partial pressure of air within the instruments. Distillation is negligible below the threshold, but above, it is proportional to the excess radiation. Because the relation between absorbed heat and radiation incident on a horizontal surface depends on solar altitude and on the proportions of direct and diffuse radiation, it is difficult to predict field response from laboratory data.
Some long‐term means from The Phenological Reports (1891–1948) of the Royal Meteorological Society
Authors: Jeffree E. P. 
Published: February 2007

AbstractThe Phenological Reports 1891–1948 of the Royal Meteorological Society are discussed; interpolated values in floral records have been re‐calculated, and 58‐yr district and British Isles weighted means, and annual differences from these, have been calculated for 11 flowering events. 20‐yr means and differences have been similarly calculated for a further 14 events, and the former approximately corrected to the 58‐yr means. For 11 main flowers in The Phenological Reports, the mean difference in flowering dates between south and north Britain was 21 days later for a distance of some 400 mi farther north. Extremes of earliness and lateness have been tabulated for the British Isles weighted means for these 11 flowers over the years 1891‐1948. Extreme earliness averaged 17‐7 days and extreme lateness 17‐1 days, but while extremes of earliness were fairly constant throughout the year or possibly became a little greater for summer than for spring flowers, extremes of lateness were much greater for spring than for late summer flowers. These differences are directionally in keeping with the finding of Hawke (1941) that in the winter months abnormally low temperatures are much more extreme than abnormally high values, while in summer the abnormally high values are more extreme than the exceptionally low. The standard deviations for the annual values of the British Isles weighted means are also given, and averaged 7‐0 days for the 11 main flowers.
Determination of the straight line of best fit to observational data of two related variates when both sets of values are subject to error
Authors: Morgan W. A. 
Published: February 2007

AbstractThe general equation to a straight line of best fit to observational data of two related variates x and y is obtained by minimizing the general expression \documentclass{article}\pagestyle{empty}\begin{document}$ \sum\limits_{i = 1}^n {(y_i - ax_i - b)^2 } $\end{document} ϕ(a) involving the departures of both variates from the time. It is shown that the only expression for ϕ (a) which produces consistent results with change of unit is ϕ (a) = constant. ak, where k depends on the relative errors (ex, ey) in measurements of the two variates.The line of best fit is shown to be

where c is obtained from the equation (k + 2) c2 – 2 (k + 1) rc + k = 0, in which r is the coefficient of correlation between x and y, and k is a given function of ex and ey. The usual regression lines and line with a slope equal to the geometric mean of the slopes of the two regression lines, arise as special cases of the general equation. Examples are given to show general application.
A direct measurement of the humidity in the stratosphere using a cooled‐vapour trap
Authors: Barclay F. R. , Elliott M. J. W. , Goldsmith P. , Jelley J. V. 
Published: February 2007

AbstractA vapour trap designed for sampling the water vapour and carbon dioxide of the stratosphere is described. The results of one flight at about 27 km over south‐east England are given and discussed.
Control of inversion height by surface heating
Authors: Ball F. K. 
Published: February 2007

AbstractViscous dissipation is inadequate to account for the destruction of all the thermal turbulence generated by upward transfer of heat in a deep convection layer. It is suggested that the surplus turbulent kinetic energy is destroyed by buoyancy forces in a region of downward transfer of heat in the upper part of the convection layer. This process is associated with mass transfer downwards through the convection (or subsidence) inversion and also with an upward movement of the inversion, though the latter may be overcome by sufficiently strong subsidence. A simple theory of the process is developed and the results deduced thereby agree well with observations of the diurnal variation of inversion height in Central Australia.
Fog‐droplet sampling using a modified impactor technique
Authors: May K. R. 
Published: February 2007

AbstractPossible errors in sampling fog droplets with the cascade impactor are discussed and data are presented which were obtained from 25 fogs by the use of a specially modified impactor in a small portable wind‐tunnel. A very wide range of drop diameter (< 1 to > 100 μ) was found, with great numbers of very small drops and great variability in size‐distribution. Agreement between the visual range as calculated from the drop measurements and the actual visual range was usually closer than a factor of two, though in some cases there was no such agreement.
The penetration of interfaces by cylindrical thermals
Authors: Richards J. M. 
Published: February 2007

AbstractA theory is presented which connects the proportion of a cylindrical thermal which indefinitely penetrates any specified interfacial discontinuity of density with the distribution of density excess or deficit within similar thermals moving through unstratified surroundings. The relation between the proportion of the thermal which so penetrates and the strength of the inversion has been determined experimentally; the results are expressed by the empirical formula Y = (0·93 S + 1) exp (‐ 0·93 S), where Y is the fraction of the mass of the substance released which penetrates, and S = Δp1 A1/M, where Δp1 is the change of density across the interface in the direction of motion of the thermal, A1 is the measured cross‐sectional area of the thermal when its widest part is at the initial level of the interface, and M is the initial mass excess of the thermal per unit length. The theory then predicts that, in cylindrical thermals moving through unstratified surroundings, T/A = exp (‐ Δp A/M), where A is the average cross‐sectional area of the thermal, M is its mass excess or deficit per unit length, and T is the total average cross‐sectional area of all regions within which the density excess or deficit, respectively, is greater than or equal to Δp.Mean cross‐sectional distributions of a passive pollutant have been determined experimentally in three thermals moving through unstratified surroundings. The results were roughly consistent with the expression α/A = exp (‐ $C/$C), where A has the previous meaning, $C is the average concentration of the pollutant over the whole thermal, and α is the mean total cross‐sectional area of all regions within which the concentration of pollutant, averaged over the length of the thermal, is everywhere greater than or equal to ΔC.These and other observations seem to show that cylindrical thermals are usually appreciably non‐uniform along their lengths.
The formation of ammonium sulphate in water droplets exposed to gaseous sulphur dioxide and ammonia
Authors: Van Den Heuvel A. P. , Mason B. J. 
Published: February 2007

AbstractThe rate of formation of ammonium sulphate in water drops exposed to air containing known concentrations of gaseous sulphur dioxide and ammonia has been measured. The mass of sulphate formed is proportional to the product of the surface area of the drops and the time of exposure. Extrapolation of the laboratory results to the atmosphere suggests that the large condensation nuclei 0·2 μ < r < 1 μ of ammonium sulphate, found by Junge to be abundant in industrially polluted air, are formed by the absorption of SO2 and NH3 in cloud and fog droplets.
The absorption of solar infra‐red radiation by the lower stratosphere
Authors: Houghton J. T. 
Published: February 2007

AbstractAircraft observations of the absorption of solar infra‐red radiation by the atmosphere are compared with values of integrated absorption predicted from laboratory measurements on water vapour and carbon dioxide. Aircraft observations of bands due to O2, CO, CH4 and N2O are also considered. A scheme is derived for computing, for different latitudes and seasons, the heating‐rate due to the absorption of solar infra‐red radiation at altitudes between 10 km and 40 km. The results of such computations are presented.
A note on the frictional boundary condition at the earth's surface in relation to a model of the general atmospheric circulation
Authors: Oakes M. B. 
Published: February 2007

AbstractIn a paper by Davies and Oakes (1962) concerning the problem of formulating a model of the general atmospheric circulation, the boundary condition used at the surface of the earth involved the assumption that the surface meridional, zonal, and vertical velocities are zero. In this note the effect on the model is evaluated by using as boundary condition at the earth's surface the more realistic assumption that the Reynolds stress is proportional to the first power of the surface wind speed.
The motion and structure of stellar shadow‐band patterns
Authors: Protheroe W. M. 
Published: February 2007

AbstractThe structure of stellar shadow bands has been measured on eighteen nights using an optical Fourier analyser technique. The mean size of the pattern elements was found to be 15.6 cm. The measured pattern speed and direction of motion agreed reasonably well with the upper‐air winds in the neighbourhood of 30,000 ft. The lifetime of the shadow‐pattern elements was found to be of the order of tens of milliseconds.
Factors affecting the heat transfer from hailstones
Authors: Macklin W. C. 
Published: February 2007

AbstractThe rate of heat transfer by forced convection from rotating and oscillating spheroids of ice has been investigated and it is shown that these factors are unlikely to influence the rate of heat transfer from hailstones. Turbulence, however, does affect the rate of heat transfer and it is suggested that some of the transitions from clear to opaque ice observed in hailstones could be caused by the influence of the turbulent wake of one hailstone on another.The effect of prolonged melting on shape is also discussed.
An index of clear air turbulence
Authors: Colson D. , Panofsky H. A. 
Published: February 2007

AbstractAn index is derived for the intensity of turbulence in a sloping baroclinic layer. Preliminary estimates of this index from ordinary meteorological information suggest that the index is proportional to turbulent energy and that it discriminates better between regions of varying intensity than vertical wind shear or Richardson number. An exact test, however, would require more detailed synoptic information than is usually available.
Radiation balance of natural and agricultural vegetation
Authors: Stanhill G. , Hofstede G. J. , Kalma J. D. 
Published: February 2007

AbstractThe three constants of a radiation‐balance equation ‐ albedo, heating coefficient and long‐wave radiation balance at zero insolation ‐ have been derived from linear regression equations relating measurements of incident and reflected short‐wave radiation to measurements of radiation balance (all wave‐lengths) made over nine different associations of natural vegetation and two agricultural surfaces. Albedo was found to be the most important discriminant in the relationship, varying from 0.12 for a pine forest to 0.37 for vegetation in a desert wadi. The diurnal and seasonal variations were small and of limited significance. The heating coefficient varied considerably, both with date of measurement and with vegetation, but no consistent differences could be seen. The values found were very low, even negative on a number of occasions. These were associated with a mid‐day decrease in the long‐wave balance attributed to a marked increase in the long‐wave flux from the sky. The long‐wave balance at zero insolation also varied considerably with date of measurement and type of surface but showed only small differences in long‐term mean values.Daily totals of net radiation balance expressed as percentages of total incoming short‐wave radiation varied from a maximum of 58 per cent for the open water surface of a fish pond to a minimum of 25 per cent for a desert association. The ratio for most vegetation was close to 50 per cent.