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A REVISED ANALYSIS OF SOLAR-CONSTANT VALUES 



By C. G. abbot 



Research Associate, Smithsonian Institution 



In volume 6, Annals of the Smithsonian Astrophysical Observatory, 

 revised lo-day and monthly mean values of the solar constant of radia- 

 tion, August 1920 to September 1939, were given in table 27. From 

 these data 14 regular periodic variations of the sun's output of radia- 

 tion were discovered as stated on page 181. These periodic varia- 

 tions are set down in table 2)-, as they progressed from 1920 to 1939. 

 They were synthesized to give the curve marked B in figure 14. This 

 synthetic curve was produced forward, through 1945, as a prophecy. 

 There was satisfactory verification until late in 1944. Great interest 

 was taken in the march of the prophetic curve in the years 1944 and 

 1945, for it indicated a considerable depression, somewhat like that 

 observed in 1922 and 1923, as shown in greater detail in figure 12 

 of the Annals. 



L. B. Aldrich, Director of the Observatory, having now kindly 

 given me the solar-constant observations up to the end of 1945 in final 

 form, I wished to see if the great depression occurred in 1945 as 

 expected, and whether the prophecy was generally fulfilled within ex- 

 perimental error. 



It is to be regretted that the long series of solar-constant values, 

 1920 to 1945, has several less satisfactory intervals. First, as stated 

 on page 168 of the Annals, volume 6, was the critical interval 1921 

 and 1922. At Montezuma (our best station), as may be seen by refer- 

 ring to volume 5 of the Annals, pages 195 to 199, on the average only 

 3.4 days per decade were observed there from December 21, 1920, 

 to February 28, 1923. 



The excellent station on Mount Saint Katherine, in Egypt, where 

 observations were made from January 1934 to November 1937, had to 

 be abandoned because of wars. Hence no support to Montezuma work 

 came from there from 1938 to 1945. 



The station at Tyrone, in New Mexico, from which observations 

 came after February 1939, fell more and more behind our hopes as 

 time went on. One disturbing factor was variable smoke arising from 



SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 107, NO. 10 



