摘要:

AbstractThe transfer of heat and momentum by motion on the scale of cyclone waves and long waves is deduced from a knowledge of their mechanics. The law of horizontal transfer of entropy is independent of notions of mixing but is similar to that for non‐isotropic diffusion. The law accurately represents the annual variation of heat‐flux in the Northern Hemisphere. Perturbation theory suggests realistic spatial variations for the transfer and provides a rational basis for calculating transfer coefficients which can then be used to find the flux of other conservative quantities. Most importantly the Equatorward flux of potential vorticity is well defined and is shown to determine the horizontal flux of momentum uv. The mean surface winds, and the mean meridional circulation (which is seen to be frictionally driven) are then determined. A model of the general circulation is defined by these properties, and this is integrated analytically for a simplified case and compared with motion observed in the Gulf Stream, the mesosphere, and dishpan experiments as well as the troposph

ISSN:0035-9009    

DOI:10.1002/qj.49709640802

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractMonthly‐mean zonal wind data from approximately 200 rawin stations have been filtered to remove the annual and shorter period variations. Data from 1950–1964 for levels from 700 to 7 mb were analysed. The primary variation is the quasi‐biennial oscillation of the equatorial stratosphere and its extension to higher latitudes. There is much greater variability with longitude and time of the weak quasi‐biennial oscillation at higher latitudes than observed in the equatorial stratosphere. However, as the vertical and meridional phase progression patterns of the oscillations in both troposphere and stratosphere are systematic, these properties are probably real. The main fluctuations can frequently be traced from the surface to at least 35 km except in the middle latitudes of the Northern Hemisphere where the stratospheric variations often do not appear related to those of the troposphere. The most organized phase progressions with latitude are the apparent opposite ones observed in the stratosphere and troposphere of the Northern Hemisphere. Prior to 1960, well‐defined poleward progression is observed in the troposphere (300 mb), while weaker Equatorward progression is evident in the stratosphere (30 mb). In 1961 the pattern reverses, with poleward progression at 30 mb and Equatorward progression at 300 mb. In the tropical stratosphere during the years 1960–1961, the quasi‐biennial oscillation was characterized by unusually low amplitude, short‐peri

ISSN:0035-9009    

DOI:10.1002/qj.49709640803

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractAn account is given of the development and application of a system for the study of high altitude winds using the radio meteor method. Three main subjects have been investigated : atmospheric tides and short term wind oscillations possibly resulting from internal atmospheric gravity waves, wind shears in the meteor zone and finally the nature of drifts obtained with the spaced receiver ionosonde technique. The Sheffield system has been steadily expanding and current developments as well as other projects linked with the Sheffield experiment are described.

ISSN:0035-9009    

DOI:10.1002/qj.49709640804

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractLarge changes in the temperature and ozone content of the stratosphere at Aspendale (38 S, 145 E), Hobart (43 S, 148 E) and Macquarie Island (54 S, 160 E) are associated with the passage of planetary waves in the Antarctic polar vortex. Application of the conservation equation to an elliptical model of the polar vortex, using both ozone and potential temperature as tracers, leads to order of magnitude estimates of the vertical and horizontal motions and transports involved. Estimated vertical motions are of the order of 1 cm s−1.At the 30‐mb level there is significant horizontal advection of ozone into the vortex in the vicinity of the cold troughs and out of the vortex near the ridges, but horizontal advection of heat appears to be negligi

ISSN:0035-9009    

DOI:10.1002/qj.49709640805

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractA feed‐back relationship, at least in the statistical mean, between Atlantic sea surface temperatures on the one hand and monthly atmospheric circulation anomalies on the other hand, is demonstrated for the north‐east Atlantic and western Europe. The key area in the Atlantic is a wide area south of Newfoundland; colder than usual ocean surfaces in this area are shown to be associated with blocked atmospheric patterns the following month over northern and western Europe while a warmer than usual ocean in the same general area favours more progressive synoptic types to follow. Month to month changes in this general relationship are described in some detail and the application to long‐range forecasting in the British Isles is discussed. One other pattern of Atlantic sea surface temperature anomaly is also described and associated with atmospheric circulation patterns to follow.Possible inter‐relationship between the Atlantic and Pacific Oceans in respect of the effects of ocean surface temperatures on circulation patterns is also briefly con

ISSN:0035-9009    

DOI:10.1002/qj.49709640806

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe internal circulation and the shape of water drops falling at terminal velocity in air of 20°C at sea level pressure, and nearly water saturated, were studied by means of a wind tunnel. Drops with an equivalent radius a0smaller than 140 üm had within the experimental error no detectable deformation from spherical shape. Drops of sizes 140 μm ≤ a0≤ 500 μm were slightly deformed into an oblate spheroid. The deviation of these drops from spherical shape was found to be in fair agreement with that theoretically predicted by Imai (1950) and others. The deformation of drops of sizes 0.5 mm

ISSN:0035-9009    

DOI:10.1002/qj.49709640807

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractExperimental studies have been made of the aggregation of ice crystals of mean diameter about 5 μm upon an ice sphere of diameter 0.2 cm at the same temperature. The growth rate was found to be roughly independent of temperature over the range − 7°C to − 27°C and increased with electric field strength E to exceed the field‐free value by about 15 per cent, 40 per cent and 80 per cent in fields of 500, 1,000 and 1,500 V cm−1respectively. At higher values of E the growth‐rate was reduced because of the ejection of clusters of ice crystals from the aggregate, probably under the influence of the intense electric forces. An appreciable amount of aggregation was observed at temperatures as low as − 37°C, in the presence or in the absence of electric fields.Absolute values of collection efficiencies at a velocity of 3 m s−1were determined at the temperatures − 7°C, − 11°C, − 17°C and − 27°C. In the absence of an electric field collection efficiencies of about 0.3 were determined at all temperatures studied. Experiments with charged ice crystals indicated that electric fields increase the growth rate by increasing the adhesion efficiency and

ISSN:0035-9009    

DOI:10.1002/qj.49709640808

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractMeasurements have been made, using a precision balance, of the electrostatic forces exerted on scaled‐up metallic models of cloud droplets and, particularly, ice crystals, as a function of their charges, configurations and proximity to a second model, together with the strength of the electric field E in which they were situated and the angle θ between the direction of the field and the line of centres of the models.It was found that the electrostatic forces on metallic spheres agreed closely with those calculated from the equation of Davis (1964). The forces on irregularly shaped uncharged metallic models of ice crystals were generally larger than those on spheres of equivalent volume to the crystals by a factor γ which was shown to be independent of E and θ and, in general, extremely insensitive to the separation over the range of conditions studied.The measured values of γ, together with the values of the equivalent radius Reof a crystal, deduced directly from its volume, were incorporated into a modified form of Davis' equations which should be useful in computations of the collision efficiencies of uncharged ice cry

ISSN:0035-9009    

DOI:10.1002/qj.49709640809

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractDuring a routine instrumentation flight check in the lower stratosphere periodic variations of temperature and winds were observed. It is deduced that these variations are gravity waves which appear to be associated with a narrow frontal zone separating regions with different potential temperatures. Vertical and horizontal wind changes of ± 1 m s−1and potential temperature variations of up to ± 2°C are measured with a wavelength of 2.3 km. The breakdown of waves such as these may be associated with observations of clear air turbulence in the stratosphere along shear layers separating weak flows of different or

ISSN:0035-9009    

DOI:10.1002/qj.49709640810

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe predicted air motion and precipitation patterns obtained from a 10‐level primitive equation model of the atmosphere are presented for comparison with the observed patterns analysed by isentropic and Doppler radar techniques for the same occasion by Browning and Harrold (1969). There is considerable agreement over the scales of motion which it is possible to predict using the model though it is possible that further refinement in the handling of friction and topography and of the cloud physics can improve the predicted overall large‐scale distribution of rainf

ISSN:0035-9009    

DOI:10.1002/qj.49709640811

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY