KoeblinQ ipund 



A REMARKABLE REVERSAL IN THE DISTRIBUTION 

 OF STORM FREQUENCY IN THE UNITED STATES 

 IN DOUBLE HALE SOLAR CYCLES, OF INTEREST 

 IN LONG-RANGE FORECASTING 



By C. J. KULLMER i 



We have for the United States the only long fairly uniform series 

 of maps of tracks of barometric depressions. These have been pub- 

 lished in the Monthly Weather Review for each month from 1874 

 to the present. Dunwoody assembled the material for the lo-year 

 international period, 1878-87, in storm-frequency maps for the whole 

 Northern Hemisphere. Dunwoody's method was to divide the maps 

 into 5° squares and record the number of centers of barometric de- 

 pressions that crossed each square. In 191 1 I remade the maps of 

 storm frequency in the United States for 1899-1908 according to 

 Dunwoody's plan of 5° squares.- In the interval of 21 years a sHght 

 but definite southerly and westerly shift had taken place. But 5° in 

 latitude, about 345 miles, is evidently unnecessarily large if we wish 

 to test latitude shifts. I wished to ascertain whether there is any 

 correspondence between the latitude shifts of sunspots and the lati- 

 tude of the vortexes in our own atmosphere. Accordingly, I cut 

 Dunwoody's square in half, making the unit 5° in longitude and 2|° 

 in latitude, and made in 1913 a series of year maps from 1874 to 

 1912, furnishing comparison material for three solar cycles. Since 

 that time three more solar cycles have become available. The 

 results for the five cycles, with a series of year maps, 1883-1930, 

 appeared in 1933 in a Smithsonian publication.^ I shall now present 

 the results for the last solar cycle. 



1 Published posthumously ; Dr. Kullmer, formerly of Syracuse University, 

 died in 1942. 



2 The shift of the storm track. Chap. 16 in Huntington, The climatic factor, 

 Carnegie Inst. Publ. 192, 1914. 



3 Kullmer, C. J., The latitude shift of the storm track in the ii-year solar 

 period, Smithsonian Misc. Coll., vol. 89, No. 2, 1933. Preliminary publication 

 of parts of the study appeared in Huntington, The solar hypothesis of cli- 

 matic changes, Bull. Geol. Soc. Amer., vol. 25, pp. 477-590, 1914. See also 

 Huntington, Earth and Sun, Yale Univ. Press, 1923. 



Smithsonian Miscellaneous Collections, Vol. 103, No. 10 



