NO. 2 LATITUDE SHIFT OF STORM TRACK KULLMER 3 



It also allows shifts in longitude to appear; in fact, the longitude 

 shifts are almost as significant as the latitude shifts. 



The most striking feature of the resulting maps is that all five maps 

 present the same pattern: i, a curved area of excess during solar 

 maximum, with a southerly projection (I have drawn a dotted line 

 through this area and its southerly extension) ; 2, south of this, and 

 on both sides of the southerly projection, areas of deficiency during 

 solar maximum ; 3, more variable areas of excess adjacent to the areas 

 of deficiency. 



The areas of deficiency are separated from the main area of excess 

 by about 6°-8° of latitude. But the location of the main area of excess 

 is subject to a displacement in both longitude and latitude. In Figure i 

 I have assembled the dotted lines drawn through this area of excess 

 and its southerly projection. In the eastern extremity they follow 

 almost a common path. After watching the eastward advance of the 

 southerly projection in periods II, III, and IV, it came as a distinct 

 surprise to find that in period V the whole system had gone back to a 

 position even farther west and south than in period II, and that the 

 large excess in Western Canada had given place to a relatively large 

 deficiency. There seems to be an indication of a cycle of three solar 

 periods : period I has almost the same position as period IV ; the 

 periods II, III, and IV seem to show an orderly progression. If these 

 represent a cycle, then period \^ is the first of the next cycle, and, 

 to make my meaning clear, the coming solar period should occupy 

 the position VI, given by the dotted line. 



It should be noted that the maxima are in each case compared with 

 a preceding minimum ; the approaching solar minimum will give an 

 opportunity to remake these maps for five solar periods to bring 

 out the comparison of maximum with follozmig minimum, which is, 

 of course, the true period. 



SUMMARY 



A latitude shift of the storm track in the United States, correspond- 

 ing to Spoerer's latitude shift of sun spots, is demonstrated for five 

 solar periods by a comparison of three year maps of storm frequency 

 at solar maximum with three year maps at solar minimum. A uniform 

 pattern of distribution is shown with marked variation in latitude and 

 longitude in the five solar periods. 



