摘要:

AbstractThe annual temperature deviations at over 400 meteorological stations are combined on a regional basis to give the integrated fluctuations over large areas and zones. These are shown in graphical form, and it is concluded that a solar or atmospheric dust hypothesis is necessary to explain the world‐wide fluctuations of a few years duration. An important change in the relationships of the zonal fluctuations has occurred since 1920. The overall temperature trends found from the data are considered in relation to the homogeneity of recording, and also to the evidence of glacial recession in different zones. It is concluded that the rising trend, shown by the instruments during recent decades, is significant from the Arctic to about 45°S lat., but quite small in most regions below 35°N. and not yet apparent in some. It is thought that the regional and zonal distribution of recent climatic trends is incompatible with the hypothesis of increased solar heating as the cause. On the other hand, the major features of this distribution are not incompatible with the hypothesis of increased carbon dioxide radiation, if the rate of atmospheric mixing between the hemispheres is a matter of decades rather than ye

ISSN:0035-9009    

DOI:10.1002/qj.49708737102

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49708737103

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

摘要:

AbstractQuasi‐periodic wind variations with height have been commonly observed in the lower stratosphere by means of the radar‐sonde theodolite at Crawley. The atmospheric disturbances which give rise to these wind variations have a vertical dimension of 1 km or so, but their horizontal dimensions must be much greater, perhaps of the order of several hundred kilometers. Perturbation theory is used to show that slow ‘inertia oscillations’ with a period of the order of half a day might have such dim

ISSN:0035-9009    

DOI:10.1002/qj.49708737104

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

摘要:

AbstractThe quality of a series of objective analyses of synoptic charts has been examined and it has been found that statistically the discrepancies from manual analyses are of the same order as the variations which arise amongst conventional analyses by different individuals. A systematic fault in the computed analyses of surface maps (viz. an underestimation of the depth of intense depressions over the ocean) was found to be due to the use of the geostrophic approximation and to other limitations of the interpolation system. Modifications designed to overcome this shortcoming have raised the standard of the analysis of depressions to that of the analyses as a whole.

ISSN:0035-9009    

DOI:10.1002/qj.49708737105

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

摘要:

AbstractIn this paper an estimate is made of the energy absorbed by wave motion at the interface of two superposed fluids when a body passes from one fluid to the other. The fluids are supposed perfect, incompressible, and bounded only by the interface, and axi‐symmetric and symmetrical two‐dimensional cases are considered. The body is supposed to move vertically and approach the interface from a great distance, and after crossing the interface to recede to a great distance, the speed being kept steady throughout. It is assumed that there were no waves originally present at the interface and that no splashing occurs during the crossing. The linear approximation to irrotational waves is used at the interface, and the slender body approximation is used at the boundary of the body. Transform methods are used to solve the Laplace equation for the velocity potential. Expressions are found for the waves set up as the body crosses the interface, and the energy used to generate the waves is found from a calculation of the work done against the wave resistance. The wave energy may be regarded as the sum of the wave energies for two cases : one in which the density difference between the two fluids is small, and another, in which the density of the upper fluid is zero. For the special cases of a spheroid and a spindle‐shaped body, curves are shown of the wave energy against a dimensionless form of the inverse speed. Criteria are given for when maximum wave energy is developed for a thermal, and an estimate of this energy is made. This is done in Sect

ISSN:0035-9009    

DOI:10.1002/qj.49708737106

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

摘要:

AbstractRoutine observations made in transport aircraft in January and July, 1955–57, are analysed to obtain the frequency of ice accretion in relation to air temperature and of turbulence in relation to wind speed and cloud. Comparative freedom from icing in the range 0° to – 3°C is attributed to the effects of kinetic heating. In January the frequency attains a maximum of 43 per cent of occasions in cloud at – 4° to – 7°C; in July 20 per cent at – 4° to – 11°C. There is a secondary maximum in both months near the lowest temperatures at which icing is reported, which is attributed to flight through the upper parts of convection cloud. The frequency of icing in July is generally much less than at the same temperatures in January.Turbulence is reported on about 5 per cent of all occasions in January and on 2 per cent in July; in cloud the frequencies are 18 and 12 per cent respectively. The frequency of turbulence tends to increase wi

ISSN:0035-9009    

DOI:10.1002/qj.49708737107

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

摘要:

Abstract599 morning weather reconnaissance flights from the Royal Aircraft Establishment, Farnborough, over a period of approximately four years have been examined to determine the frequency of occurrence and thickness of layer cloud over Southern England. The chance of encountering 4/8 or more layer cloud in any kilometre height range decreased with height from about 1 in 2 near the surface to about 1 in 50 at a height of 12 km. Cloud layers when encountered were more likely to exceed one or two kilometres depth in the upper troposphere than in the lower but the frequency of encountering a layer more than 1/12 km deep was about 7 to 8 per cent at all heights. About 1 in 9 of all flights encountered cloud above the melting level more than 3 km thick. An examination of clouds in the temperature band 0 to – 15°C suggested that conditions suitable for severe clear ice formation on some aircraft might be encountered on about one per cent of flights. The same examination suggests that seeding of layer clouds by silver‐iodide smokes should produce some detectable modification of the cloud sheet on about 8 days a

ISSN:0035-9009    

DOI:10.1002/qj.49708737108

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

摘要:

AbstractMeasurements have been made of the speeds of ice objects resembling hailstones during free fall, and of the drag coefficients of such objects and of natural hailstones. It has been found that the drag coefficients range from those of spheres (about 0·45) to about 0·8, depending on the shape and surface characteristics of the ston

ISSN:0035-9009    

DOI:10.1002/qj.49708737109

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

摘要:

AbstractIn this paper, the problem of the spatial expansion of a cluster of particles under the action of turbulence is investigated. The basic difficulty, that this form of diffusion depends on the Lagrangian properties of the turbulent field, is met by the assumption that the Lagrangian and Eulerian time‐correlograms are functionally similar. In consequence, it is possible to solve the equation governing the cluster's expansion to give prediction laws expressed only in terms of easily measured parameters of the turbulence. The application of the full solution is lengthy but a simple working approximation follows from the fact that over an important part of the expansion at which the size of the cluster is of the same order of magnitude as the Eulerian length‐scale, the rate of expansion is approximately constant and is proportional to the square of the intensity of turbulence whilst independent of the length scale itself. Experiments to test these formulae have been carried out on the diffusion of clusters of Lycopodium spores over a few hundred metres downwind travel near the ground, and the diffusion of long crosswind clouds of aircraft‐released fluorescent particles, sampled along the vertical, after several kilometres travel in the free atmosphere. Whilst the experiments are few in number and the conditions often did not strictly conform to the conditions of isotropy and homogeneity required by the theory, the results are satisfactorily consistent with the prediction formulae and imply an effectively constant ratio between the scales of the Lagrangian and Eulerian time‐corre

ISSN:0035-9009    

DOI:10.1002/qj.49708737110

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

摘要:

AbstractObservation from outside the atmosphere of the emission from different wavelength regions in the 15μ carbon‐dioxide band, would give information of the vertical temperature distribution between 10 and 50 km altitude. The measurements required are feasible using a Fabry‐Perot interferometer, and sample calculations of the depth in the atmosphere of the origin of this emission are prese

ISSN:0035-9009    

DOI:10.1002/qj.49708737111

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY