摘要:

AbstractProvisional figures can now be given for the ratio of momentum in the southern circumpolar westerlies to the momentum of the better known northern system. This ratio appears to be 1·5, or rather more, over the year as a whole and rises to over 4 in the northern summer‐southern winter.The preponderance of the southern system is such that it may be regarded as the ‘flywheel’ of the general atmospheric circulation and there are indications that changes in the southern westerlies entail world‐wide adjustments.Preliminary survey at the 500 mb level shows the main trough south of 40°S centred about 100°–110°E at most seasons of the year and the principal ridge in the neighbourhood of the outer reaches of the Ross Sea. The mean troughs and ridges have notably smaller amplitude than in the northern hemisphere. Control of trough and ridge positions appears to be thermal rather than orographic, associated with the position of the broadest part of the Antarctic cooling surface. Little seasonal movement of the troughs and ridges in longitude is discerned and no very great change of circulation intensity, but there is an intensification of flow and increase of amplitude in the Indian Ocean trough from summer to late winter.The pattern of glaciation, as well as available data on depression tracks and anticyclone distribution over the Southern Ocean, support the pattern of ridges and troughs at 500 mb here described and throw light upon the occurrence of blocking in various sectors of the southern hemisphere.This study suggests that it may be the momentum and energy of the southern westerlies which are ultimately responsible for maintaining the meteorological equator on average north of the geographical equator, at least over the oceans.In any climatic epoch when the southern westerlies were (i) farther south than now, and/or (ii) weaker than now, the meteorological equator should under this proposition have been nearer the true equator than is now the case. The work of other investigators has suggested that the equatorial low‐pressure belt should also be wider at times when the circumpolar westerlies weaken in either hemisphere. The changes here postulated appear to fit in with what is known of conditions around, and since, the culminating phase of the ‘Little Ice Age’ in the northern hemisphere about a cen

ISSN:0035-9009    

DOI:10.1002/qj.49708536302

出版商:John Wiley&Sons, Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractIt is shown that the equation determining the streamlines of large‐scale atmospheric motions (jet streams and long waves) is similar to the equation determining the streamlines of small‐scale gravitational motions of a stratified liquid. Both motions are characterized by the occurrence of jets, the number of jets being determined by the value of a dimensionless parameter. Atmospheric flow at 500 mb is compared with theoretical solutions (derived by Long 1955) of the non‐linear equations for the flow of a stratified liquid. Linearization of the equation for large‐scale atmospheric motions leads to the Rossby wave equation, whereas linearization of the equation for the motion of a stratified liquid leads to Scorer's lee‐wave

ISSN:0035-9009    

DOI:10.1002/qj.49708536303

出版商:John Wiley&Sons, Ltd    

年代:1959

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49708536304

出版商:John Wiley&Sons, Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractThe forces on two moving spheres are found from the Stokes equations of motion, full allowance being made for the mutual interference of the flows round the spheres, and the relative trajectories when they are falling under gravity are calculated so that the collision efficiencyEcan be found. The values ofEare determined for drops of radius up to 30 μ colliding with droplets of any smaller size. The results differ widely from those found by Pearcey and Hill (1957) and it is suggested that the reason for the discrepancy is that the motion of the spheres when they are close together is of great importance in determiningE. The results also differ from those found by Schotland and Kaplin (1956). Their experiments did not model the ratio of the density of the spheres to that of the medium through which they are falling and since it is shown that this factor is of importance, their results are not considered applicable to water drops falling in air

ISSN:0035-9009    

DOI:10.1002/qj.49708536305

出版商:John Wiley&Sons, Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractContinuous records of soil temperature at Muguga, Kenya, (1° 13'S, 36° 38′E) under bare soil at nominal depths of one, three and six inches and one, two and three feet were taken for the period 1954–1955.The form of the temperature wave proved remarkably constant from day to day and the diurnal variation was measurable down to about one foot. The mean of maximum and minimum temperature is a good approximation to the daily mean temperature, as obtained by numerical integration, at depths of 6 in. and over. Nearer the surface, however, the mean of maximum and minimum gives an overestimate of the daily mean temperature. The annual soil temperature wave was not sufficiently marked to justify a mathematical analysis, but the mean diurnal wave for selected ten‐day periods was analysed and values of thermal diffusivity were computed for the depth ranges 1‐6 in. and 6‐14 in. Despite seasonal changes in soil moisture content, diffusivity values proved remarkably constant with mean values of 0·0020 and 0·0015 cm2sec−1respectively for the two depth ranges. There was no obvious correlation with soi

ISSN:0035-9009    

DOI:10.1002/qj.49708536306

出版商:John Wiley&Sons, Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractThe measurement of evapotranspiration from large land areas is, like the measurement of evaporation from large areas of water, a formidable problem and not often accurately accomplished. Nevertheless, it is essential for an engineer to try to check the results of theoretical or empirical analyses, or small‐scale experiments, against nature where natural phenomena are concerned and the results of an analysis of the hydrology of the Thames are presented herein. Conclusions favouring the Thornthwaite method are reache

ISSN:0035-9009    

DOI:10.1002/qj.49708536307

出版商:John Wiley&Sons, Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractMeasurements of the atmospheric potential gradient made on a glacier at an altitude of 1,700 m showed a behaviour considerably simpler than is normally found near the ground. The nearness of the cloud, and the absence of point discharge for some kilometres gave a clear‐cut distinction between snow and rain, these almost always being associated with positive and negative fields respectively. The results suggest that the electrification processes are associated with the precipitation in both cases, and that marked electrical effects accompany the melting of sno

ISSN:0035-9009    

DOI:10.1002/qj.49708536308

出版商:John Wiley&Sons, Ltd    

年代:1959

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49708536309

出版商:John Wiley&Sons, Ltd    

年代:1959

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49708536310

出版商:John Wiley&Sons, Ltd    

年代:1959

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49708536311

出版商:John Wiley&Sons, Ltd    

年代:1959

数据来源: WILEY