SOLAR VARIATION AND WEATHER 



Bv C. G. ABBOT 



Research Associate, Smithsonian Institution 



From 1920 to 1955, with the aid of John A. Roebling, the Smith- 

 sonian Astrophysical Observatory under my direction, and later 

 under that of L. B. Aldrich, made "solar-constant" observations from 

 mountain tops in cloudless deserts in Africa, Asia, South America, 

 and the United States. Although all the results were highly accurate, 

 they were especially so from 1924 to 1944, for it was not till 1924 

 that the "short method" was fully perfected, and after 1944 the 

 transparency of the atmosphere was less perfect than before. 



From 1935 to the present I have sought to correlate the solar- 

 constant measures with weather phenomena. I have published in 

 Smithsonian Miscellaneous Collections ^ more than a score of papers 

 on this subject. These papers and the volumes of the Annals of the 

 Astrophysical Observatory, as well as several papers in outside jour- 

 nals, are referred to in the Appendix. They give in detail the evi- 

 dence I shall rely upon in what follows. 



I have been led to conclude firmly that variations of the sun's emis- 

 sion of radiation are associated intimately with weather changes. 

 Since the death of H. H. Qayton I know of no professional meteorolo- 

 gists in the world, with the exception of Dr. Irving P. Krick, who 

 have acknowledged support of my main conclusion. They all, indeed, 

 credit us with highly accurate solar measurements, but in the absence 

 as yet of connecting theory they distrust my proofs that solar varia- 

 tion has any considerable influence on ground weather. 



Being now past 91 years of age, and firmly convinced that the 

 sacrificing years of residence of my colleagues on high desert moun- 

 tains have given to astrophysics and meteorology a long series of 

 measurements of great practical importance, I feel compelled in jus- 



1 In the Appendix I give full references to all sources I refer to here. Nearly 

 all are from Smithsonian Miscellaneous Collections. For brevity in the text 

 I shall cite the Smithsonian publication number as "P." so and so. 



SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 146, NO. 3 



