ISSN:0035-9009    

DOI:10.1002/qj.49707733202

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49707733203

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractAn investigation of a large number of upper‐air soundings over regions of North America shows that the eddy transport of sensible heat is poleward in the mid‐latitude troposphere, reversing and becoming equatorward in the stratosphere. The eddy transport of sensible heat reaches its maximum in middle latitudes, decreasing both poleward and equatorward. It is shown wherein these results differ from those recently presented by Priestley. The transport of sensible heat has a high seasonal variation, being much stronger in winter than in summer. There are indications that at very low latitudes the eddy sensible‐heat transport is directed equatorward.The eddy transport of latent energy is described by means of the same soundings and is found to be poleward throughout middle and high latitudes with a maximum at the ground and decreasing with altitude. The principal seasonal variation in the transport of latent energy appears to be the northward shift of the mid‐latitude maximum from winter to summer. This maximum is not very pronounced, the transport in both seasons being relatively constant through middle la

ISSN:0035-9009    

DOI:10.1002/qj.49707733204

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe poleward transports of momentum and angular momentum, enthalpy, water vapour, and total energy are studied at a number of upper‐air stations in the high‐pressure belt. The results confirm earlier suggestions of a mean meridional circulation across this belt; this circulation is found to contribute about one half the total poleward transport of both energy and angular momentum, and also to make a substantial contribution to the maintenance of the total kinetic energy of the atmosphere. The meridional circulation appears notably stronger in winter than in summer. The poleward transport of angular momentum to the Westerlies reflects this variation, whereas there is relatively little seasonal variation in the contribution from eddy flux (horizontal rotations) or in the total generation of angular momentum in the Easterlies of low latitudes.Variations of eddy flux with height are examined and certain general features (Priestley,Q.J., 1949) confirmed. The lowest 500 mb of atmosphere make no appreciable contribution to the net eddy flow of momentum, the transport occurring mainly at the 300 mb and 200 mb levels.The results also provide a measure of the difference between total annual precipitation and evaporation in the tropical z

ISSN:0035-9009    

DOI:10.1002/qj.49707733205

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractAn attempt is made to determine the meridional eddy transport of angular momentum for the northern hemisphere in the vicinity of 30°N. latitude from upper‐wind observations for a period of six months. Two somewhat different methods of evaluation give essentially comparable results and indicate the presence of eddy transports which are ample to compensate for frictional losses of angular momentum farther north. No indications of the presence of a mean meridional circulation of the strength and character needed to produce a sensible northward transport of angular momentum are fou

ISSN:0035-9009    

DOI:10.1002/qj.49707733206

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractAn idealised advective wave is studied on the assumption of geostrophic advection of temperature. There is a genuine instability of zonal motion due to this factor and the wave form is similar to thermally asymmetrical depressions and anticyclones. The speed of the unstable waves is Ū − Uc/2 rather than the Ū − Ucof barotropic theory (Ū the mean zonal wind, Ucthe Rossby westward component due to variation of Coriolis parameter).Waves become stable when (approximately) the root‐mean‐square zonal thermal wind becomes equal to Uc. This is near the stationary wave length. There are two types of stable waves, the thermally in‐phase and the thermally antiphase waves. The antiphase waves move eastward relative to the surface zonal flow, the in‐phase waves are retrograde.The wave characteristics depend on the thermal‐wind conditions, the surface zonal wind is simply additive to the wave speed.The results support the author's development theory. They do not encourage much optimism in the direct application of barotropic concepts to the baroc

ISSN:0035-9009    

DOI:10.1002/qj.49707733207

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe difficulties of deducing a formula for the dimensions or spacing of cloudlets on the assumption that they are convection cells or unstable waves are discussed. The formula\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm wavelength = 2}{\rm .6938 h} $$\end{document}where h is the depth of the statically unstable layer is then deduced for billow clouds of a particular type, on the assumption that they consist of parallel rows of rotating masses of air moving with the mean wind of a shearing layer and sandwiched between stable wave motions above and below.

ISSN:0035-9009    

DOI:10.1002/qj.49707733208

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe rate of growth of cloud droplets round a salt nucleus is examined and it is shown that, with nuclei of the size quoted in published measurements, the drop radius achieved in the period before the droplet is carried out of the cloud layer by turbulent diffusion is in reasonable accord with published measurements of the mean drop radius. It is also shown that the maximum drop radius reached when the droplet leaves the cloud owing to fall under gravity is of the same order as the largest cloud‐drop measurements. The effect of temperature is considere

ISSN:0035-9009    

DOI:10.1002/qj.49707733209

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe charges on rain, as measured by Simpson and by Hutchinson and Chalmers, during periods when point discharge occurs, can be accounted for quantitatively on reasonable assumptions in terms of the process of ion capture. The results show that the separation of charge must operate at levels down to about 800 m, and the consequences of this are discussed in relation to theories of the process of separation of charge.

ISSN:0035-9009    

DOI:10.1002/qj.49707733210

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe diurnal variation of precipitation is discussed and attention is drawn to the high frequency of night‐time rains over central U.S.A. A new theory for explaining this nocturnal maximum and the relatively low activity of precipitation in daytime is proposed by suggesting that cooling and heating processes during the night and the day set up a large‐scale circulation system east of the Rocky Mountains. The existence of this circulation system is proved by computation of the changes which occur in the convergence‐divergence field at 4,000, 10,000 and 18,000 ft in the free atmos

ISSN:0035-9009    

DOI:10.1002/qj.49707733211

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY