20 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 39 



Table 7. — Phase adjustment. The 6-1/15-month period 



Division = Time before and after 1900. 



Category = Records when Wolf sunspot numbers g; 20. 



Phase shifts indicated: ok, ^n, 4^n, drawn dotted below. 



Basis of forecast, over 1,000 monthly records smoothed by 3-month running means. Forecasts employ 27 periods 



all exact submultiples of 273 months. 

 Phases shift with changing atmospheric conditions, but periods remain, and are of the exact lengths found i 



solar variation. It requires 220 tables electronically computed to make a forecast for one station. 



Category 2 Assembly 



Category i Assembly 



MC 



to 



Range 137» of WormalTptkl 



"-^_ Curve. LTi •' 



MEAN 

 CAT.2 



e a oK 



C.T, 



R^NGE 16% OF WoRMAL foTAL 



U.meanCat 



a ok 





Fig. 9. — Phase shifts in sixfold grouping of periods. 



