ISSN:0035-9009    

DOI:10.1002/qj.49706628302

出版商:John Wiley&Sons, Ltd    

年代:1940

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49706628303

出版商:John Wiley&Sons, Ltd    

年代:1940

数据来源: WILEY

摘要:

AbstractObservations have been made with vacuum sodium and with rectifier selenium photo‐electric cells, under opal flashed glass diffusing plates. The former may remain constant save when exposed to intense tropical desert heat and full sunshine for a long period. The latter are far less constant, and in time the curvature of the light‐current relation may increase; this is accompanied by a decrease in blue and green sensitivity so that the response at the long wave end of the spectrum becomes relatively greater. No serious temperature error is introduced when the current from a Ixeston selenium cell is measured with a 10 ohm galvanometer amid snowy surroundings.Sodium cell measurements at about 0.41 μ give the reflection from the snow as being from 0.74 to 1.19 times the vertical component of mixed daylight. With a selenium cell, sensitive throughout the spectrum, observations ranged from 0.68–0.88. Calculated on the maximum values for mixed daylight the snow reflections were from 0.38–0.74 and from 0.28–0.38 respectively for the sodium and selenium cells.Under Alpine conditions there is relatively less scattered light from the sky, consequently the sun/sky ratio is greater, in the violet, than in England or Ceylon for the same solar altitude; with the selenium cell the sun/sky ratio is even greater, with a maximum of 9.70, as against 3.55 for the violet, both determinations being made at Scheidegg (2,064 m.) with an absolutely cloudless very dark blue sky, solar altitude 48.1°.The vertical component of daylight is higher in the violet, under Alpine conditions, than in Ceylon, for low or moderate solar altitudes, but the difference is less at higher solar altitudes. For measurements covering the whole spectrum the Alpine values are also noticeably higher. The physiological effects of Alpine sunlight are due partly to the intensity of the refl

ISSN:0035-9009    

DOI:10.1002/qj.49706628304

出版商:John Wiley&Sons, Ltd    

年代:1940

数据来源: WILEY

摘要:

AbstractAn account is given of investigations on the location of sources of atmospherics in South Africa with visually‐operated cathode‐ray direction‐finders, extending over a period of fifteen months and employing stations in Johannesburg, Durban and Bulawayo.The accuracy with which a thunderstorm source can be located by this method was found to be ±50 km. for storms at distances less than 750 km. At greater distances the accuracy decreases but is usually less than ±100 km. at 1,500 km.Of the land sources 76 per cent. were identified with thunder‐clouds and 18 per cent. with nimbus cloud.Sources over the oceans were found t o be closely associated with areas of low pressure, 89 per cent of such lows having associated sources. The progress of the lows could be followed by this method for several days. Their associated sources in the majority of cases lay in the warm sector from NNE. to ESE. of the centre of the low.The monthly and seasonal distributions of sources over the land agree with the distributions found by Brooks from thunderstorm data, except that over the Indian Ocean the number of atmospherics sources reaches a maximum in the winter.A discussion is given of the possibilities of the device in meteorology in Southern Africa and of difficulties encountered in the practical day‐by‐day use of the system. A commentary follows by three officers of the Rhodesia Meteorolo

ISSN:0035-9009    

DOI:10.1002/qj.49706628305

出版商:John Wiley&Sons, Ltd    

年代:1940

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49706628306

出版商:John Wiley&Sons, Ltd    

年代:1940

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49706628307

出版商:John Wiley&Sons, Ltd    

年代:1940

数据来源: WILEY

摘要:

AbstractA belief exists in Nottingham that there is some relation between the paths of thunderstorms and the valley of the River Trent. This investigation was made with a view to testing this speculation and to discovering whether any tendency did exist in the local distribution of thunder rains round Nottingham. Information was obtained from 34 rain gauges for thunder days over a period of ten years, and the data charted and analysed.It is found that there are areas which appear to be more subject to heavy thunder rains, and also areas having a comparative immunity. There seems to be some basis for the belief that these rains do tend to be heavier near the River Trent, but this tendency is more marked for the stretch of valley between the confluences of the rivers Erewash and Leen with the Trent. Eastwards of the Leen the river valley appears to be less subject to the heaviest falls.

ISSN:0035-9009    

DOI:10.1002/qj.49706628308

出版商:John Wiley&Sons, Ltd    

年代:1940

数据来源: WILEY

摘要:

AbstractTo confirm the variation of atmospheric opacity with relative humidity, inferred in a previous paper from theoretical considerations, observations of visibility at Valentia are utilised to deduce values of atmospheric opacity. These values are grouped according to the relative humidity and the direction of the wind. Examination of the results shows beyond doubt that, in air free from smoke, opacity varies with relative humidity in a manner which corresponds very closely with that indicated by the theoretical equations, provided that in these equations suitable values are inserted for the number of nuclei and for a quantity depending on the mass of salt in each nucleus and its hygroscopic properties.

ISSN:0035-9009    

DOI:10.1002/qj.49706628309

出版商:John Wiley&Sons, Ltd    

年代:1940

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49706628310

出版商:John Wiley&Sons, Ltd    

年代:1940

数据来源: WILEY

ISSN:0035-9009    

DOI:10.1002/qj.49706628311

出版商:John Wiley&Sons, Ltd    

年代:1940

数据来源: WILEY