110 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1941 



Dr. H. Arctowski continued his meteorological investigations re- 

 lating to the effects of solar variation on atmospheric barometric 

 pressure and temperature. His studies led to researches on the 

 upper air. By courtesy of the Chief of the United States Weather 

 Bureau a long series of daily nocturnal radio-meteorograph records 

 were procured. Dr. Arctowski did very extensive computations and 

 graphical representations with these data. At the end of about 18 

 months of strenuous investigation he prepared a paper illustrated by 

 many plots and much tabular matter which will be found of source 

 value hereafter. This paper will soon issue under a Roebling grant. 

 Dr. Arctowski finds the important influence of solar variation on 

 weather plainly obvious, but the manner of its operation extremely 

 complex. He regards this first paper as merely introductory, and 

 sees a great field for future investigation. 



FIELD STATIONS 



As far as possible daily determinations of the solar constant of 

 radiation were made at three field stations, Montezuma, Chile, 

 Table Mountain, Calif., and Tyrone, N. Mex. A commodious rein- 

 forced concrete dwelling house was erected at Montezuma under 

 H. B. Freeman's direction. 



PERSONNEL 



L. A. Fillmen, for many years instrument maker in the Division 

 of Kadiation and Organisms under private support at the Smith- 

 sonian Institution, was transferred to the Astrophysical Observatory 

 Government roll. 



SUMMARY 



The immense task of preparing the solar-constant work of the 

 past 20 years for final publication was practically finished. A new 

 method of following solar variation was devised and installed at 

 all field stations. An extensive research on the effects of solar vari- 

 ation by Dr. H. Arctowski approached publication. Dr. Abbot pub- 

 lished a paper entitled "An Important Weather Element Hitherto 

 Generally Disregarded," in which many proofs of solar variation 

 were assembled, and the effects of it on weather were shown, to- 

 gether with preliminary attempts at 3- to 5-year weather forecasts 

 and verifications. These ambitious forecasts, while not as success- 

 ful as was hoped, are promising. 



Kespectfully submitted. 



C. G. Abbot, Director. 



The Secretary, 



Smithsonian Institution. 



