THE REI1A\'U)R DI- I'.A Ro.M I-:'IM<ir PRRSSURE 



DURING AXU A1''1"1:R SOLAR PARTICLE 



INVASIONS AND SOLAR UL'lkAX'lOLET 



LWASIOXS^ 



p.v p>. nrrn.L ani> g. duki.l 



GENERAL CONSIDERATIONS 



A convincing proof that there exists an influence on the large-scale 

 weather course, exerted by certain radiation invasions that are con- 

 nected with increased sun activity, would be of theoretical interest 

 for the geophysicist and also of practical importance for the meteor- 

 ologist who is in charge of the daily weather forecast. In a great 

 innnber of statistical investigations an attemjjt has been made to 

 furnish that proof. In these statistics monthly and annual mean 

 values of single meteorological elements have been correlaterl with 

 corresponding mean values of the relative sunspot numbers and 

 sometimes of the solar constant. Less frequently daily values of the 

 quoted elements have been correlated with each other, e.g., by C. G. 

 Abbot (i), H. Arctowski, (2), H. H. Clayton (3), E. Hunting- 

 ton (4), V. ^L Rubashev (5), and others. Only rarely has an attempt 

 been made to use other character numbers for the kind and intensity 

 of tlie eruptive sun activity, although such data, e.g.. the profile 

 numbers for prominences, details about j)hotospheric faculae, calcium 

 flocculi, bright and dark hydrogen flocculi, bright chromospheric 

 eruptions and characteristic brightenings of the solar corona, have 

 been available for quite a number of years. Also the difTerent kinds 

 of geomagnetic character figures, systematic ob.servations of the au- 

 rora borealis. and certain direct ionospheric multi frequency-recording 

 data, by which difTerent disturbed states of the O-, E-, F,-, and F,- 

 layers are characterized, have been largely disregarded, when the pos- 

 sibility of solar influences on the troposphere was examined statisti- 

 cally. 



' Paper read before a joint meeting of the American Physical Society and the 

 .\mcrican Meteorological Society on May i, 1947. at Washington. D. C. 



SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 110. NO. S 



