摘要:

AbstractA 10‐level primitive equation model suitable for studying the dynamics of fronts and frontal rainfall is described. The atmosphere is assumed to be hydrostatic and inviscid and the effects of friction and topography are ignored. Latent heat due to evaporation and condensation is incorporated in the thermodynamic equation. No distinction is made between the ice and water stage and the atmosphere is assumed to be dry above 300 mb. The horizontal grid length is 40 km. The results of one 24‐hr integration are described in det

ISSN:0035-9009    

DOI:10.1002/qj.49709339502

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractThe theory for the diurnal tide in the atmosphere is reviewed and the appropriate Hough Functions (including those with negative equivalent depths) are described. The main thermal drives for the diurnal tide — insolation absorption by O3and H2O — are described. The theory is then used to compute the atmosphere's response to the thermal drives. It is shown that the small amplitude of the diurnal surface pressure oscillation results from most of the thermal drive being used to activate trapped modes. The calculated winds are in reasonable agreement with observations of the diurnal wind oscillation from the troposphere to the upper mesosphere. In addition the tidal wind agrees strikingly with single time observations of the total wind in the upper‐air. The temperature and vertical wind distributions and the upward flux of energy due to the diurnal tide are also calculated. The last item amounts to 6·8 ergs cm−2sec−1at the Equator which is about 2·5 times the downward solar flux in bands absorbable in the thermosphere. The average tidal flux over all latitudes is, however, considera

ISSN:0035-9009    

DOI:10.1002/qj.49709339503

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractThe use of emissivity for calculating atmospheric radiation fluxes due to water vapour is investigated with a view to finding the most accurate way of using the approximation. It is shown that with care it is possible to adjust the emissivity so that errors in fluxes of less than 0·05 mW cm−2are incurred, when compared with calculations using more accurate methods. This can be attained with the aid of a least squares fit of emissivity on calculated flux. ‘Laboratory’ type emissivities give errors of up to 1·3

ISSN:0035-9009    

DOI:10.1002/qj.49709339504

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractArtificial snowstorms were created inside a large cold room by blowing snow crystals over a snow surface. The charges acquired by the visible blown particles and the residual snow surface and the electric fields and concentrations of positive and negative ions produced in the air above the snow surface were measured as a function of the wind velocity,U, the relative humidity, the amount of snow introduced into the air jet, and the temperature of the jet and the snow surface,TjandTsrespectively; all of these variables were monitored and recorded continuously. In a typical experiment withTj= − 20°C,Ts= −40°C,U= 430 cm sec−1, and snow crystals introduced into the air jet at a rate of 1 g sec−1the snow surface acquired a charge of 5 × 103e.s.u. in 10 sec, the charge residing on the visible blown particles was approximately equal and opposite to this amount, and the concentrations of positive and negative ions created in the air were 4,600 and 4,800 cm−3respectively, corresponding to a net charge carried on the air within the cold room of less than 1 e.s.u. The charging was found to be a sensitive function of (Tj—Ts) over a very wide range but was independent ofTsexcept at high temperatures when large‐scale melting and erratic charging were observed. The charging was found to increase rapidly asUwas increased from 1 to 5 m sec−1, and was slightly reduced as the relative humidity was raised.The measured electrification at temperatures below 0°C is shown to be entirely explicable, quantitatively and qualitatively, in terms of the temperature‐gradient effect. The charge acquired by the snow surface and the blown particles is a result of fragmentation of snow crystals which have temperature differences across them, asymmetric rubbing between snow particles and transient contact between crystals of different temperatures, all of which processes are manifestations of the temperature‐gradient effect. The primary source of the charge carried by the air is shown to be point discharge between highly charged particles.The contributions to the measured electrification of the Workman‐Reynolds effect, the Dinger‐Gunn effect and the evaporation of

ISSN:0035-9009    

DOI:10.1002/qj.49709339505

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractSpectroscopic studies of the airglow indicate that electronically excited molecular oxygen in the1Δgand1Σg+states is produced in the atmosphere. The way in which the excited states are formed in the atmosphere has been the subject of much speculation, and the present paper attempts to evaluate some of the mechanisms proposed in the light of laboratory experiments.The most probable excitation mechanism for O2(1Δg) appears to be the primary step in the photolysis of atmospheric ozone:O3+ hν (λ<3,100 Å) → O2(1Δg) + (1D).O2(1Δg+) may then be formed in the energy‐pooling process:O2(1Δg) + O2(1Δg) → O2(1

ISSN:0035-9009    

DOI:10.1002/qj.49709339506

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractA method of generating a shear flow in a wind tunnel is described. A grid of flat plates with added turbulence generators is used in conjunction with an artificially roughened floor. The velocity profile and turbulence profile produced by the grid are matched to the floor roughness so that a virtually non‐developing flow is achieve

ISSN:0035-9009    

DOI:10.1002/qj.49709339507

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractSwinbank's observations at Kerang (February 1962) are used to estimate the variation with the stability parameter ζ(≡z/L) of the Monin‐Obukhov universal function φM(≡u,∗︁−1kzδu/δz).A plot of Ri against ζ is used to derive the approximate variation of α (≡

ISSN:0035-9009    

DOI:10.1002/qj.49709339508

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractA method suggested earlier by the author to determine turbulent fluxes of heat and momentum from a measured wind profile is tested by using Swinbank's observational data.

ISSN:0035-9009    

DOI:10.1002/qj.49709339509

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractSpectral and cross‐spectral analyses applied to ageostrophic winds derived from transosonde trajectories provide some evidence for the existence of inertial oscillations in the atmosphere, with the evidence considerably stronger in the stratosphere than in the tropospher

ISSN:0035-9009    

DOI:10.1002/qj.49709339510

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY

摘要:

AbstractLinear relationships between daytime net radiation (Rn) and solar radiation (Q) have been determined for West Africa and for selected stations throughout the world. For three West African stations.Rn= 0·612Q−28And for fourteen stations throughout the worldRn= 0·617Q−24WhereRnandQare in g cal cm−2day−1.The surfaces represented have albedos ranging from 0·20 to 0·30. On average, net radiation is 55 per cent of the solar radiation. Values for a heating coefficient β, inferred from the relationships, lie between 0·14 and 0·30. The results are not consistent with some previous work. The application of the relationship to estimating evaporation and potential evapotranspiratio

ISSN:0035-9009    

DOI:10.1002/qj.49709339511

出版商:John Wiley&Sons, Ltd    

年代:1967

数据来源: WILEY