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WORLD WEATHER AND SOLAR ACTIVITY 

 By H. helm CLAYTON . 

 INTRODUCTION 



This paper is the sixth of a series by the author giving the results of 

 investigations of the relation of solar activity to atmospheric changes. 

 The earlier ones were published as Smithsonian Miscellaneous Collec- 

 tions, vol. 68, no. 3 ; vol. 71, no. 3 ; vol. yj, no. 6; vol. 78, no. 4 ; and 

 vol. 82, no. 7. The author w^ishes to express his appreciation for the 

 continuance of the encouragement in these researches by Dr. C. G. 

 Abbot and Mr. John A. Roebling. He also wishes to acknowledge the 

 help of Miss M. L Robinson in the protracted statistical work that 

 has been necessary. 



The features especially stressed in this paper are : 



1. The world-wide correlations of atmospheric changes, as indi- 

 cated by a similarity in these changes in both the Northern and 

 Southern Hemispheres and in widely separated continents and oceans. 

 In some cases the changes are directly similar, and in others the 

 changes are directly opposite— that is, when one increases the other 

 decreases. 



2. A relationship is found between atmospheric changes and sun- 

 spot activity, and an even closer relationship with changes in solar 

 radiation. 



3. Centers of action in the atmosphere are found to shift position 

 under the influence of changes in the intensity of solar activity. This 

 is a fact of great importance to be considered in correlating the 

 weather between distant places, in studying the question of periodicity 

 in the weather, and in tracing atmospheric movements of a wavelike 

 nature. 



WORLD-WIDE CORRELATION OF WEATHER CHANGES 

 In figure i a comparison is made between the mean annual rainfall 

 in the interior of the United States and the height of the Parana River 

 at Rosario, Argentina. By rainfall is meant the actual rainfall plus its 

 equivalent in other forms of precipitation. The area used is the in- 

 terior basin of the United States between the Allegheny and Rocky 

 Mountains. The data were obtained from the Monthly Weather Re- 

 view, and the mean annual values of the rainfall were computed for 



Smithsonian Miscellaneous Collections, Vol. 89, No. 15 



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