NO. 15 



WEATHER AND SOLAR ACTIVITY CLAYTON 



activity, in so far as observations permit, and are compared with the 

 values observed simultaneously at New York and Marseille. The 

 plots show that in 1883 with moderate solar activity the pressure 

 was low at Upernivik and high at New York and Marseille. In 1893 

 with increased solar activity the pressure was high at Upernivik and 

 low at New York and Marseille. In 1905 with moderate solar activity 

 the pressure was low at Upernivik and also at Yakutsk and high at 

 New York and Marseille. With greatly increased solar activity in 



CAPB Tovra 



34»S 18'a 



HIGH SOLAR ACTI7ITY 



UODBRATE SOLAR ACTIVITY 



SPOT MAX. 

 1870 



CAPE TOW^ 



\^y 



1893 



I I I 



./ 



Inch 

 ^- .004- 



- .002- 



j . 000 c: 



- -.002- 



- -.004- 



•^vSPOT MAX. 



lass 



CAPS TOOT 



^- 



•\. / 



y 



-f^t , I 



1906 

 Li_i_ 



\ 



-_UdLi4._ 



LAURIE ISL.. 



CAPE TOWM /1917\ 



I I 'i 



- ^' y '^ 



LAURIE I3'l. "^ 

 61»3x44<:« 



LAURIE ISL. 



-0.4- 



FiG. 9.— Smoothed annual means of pressure during the sun-spot 

 period, Southern Hemisphere. 



191 7 the pressure was very high at Upernivik and low at New York 

 and Marseille. These diagrams indicate that with high solar activity 

 the centers of increased atmospheric pressure move northward to 

 near 70° latitude, whereas with moderate solar activity they are found 

 near 40° latitude. The same poleward oscillation of a center of in- 

 creased pressure in the Southern Hemisphere with increased solar 

 activity is indicated in figure 9. In this diagram the smoothed annual 

 means of pressure at Cape Town are shown with high solar activity 

 on one side of the diagram and with moderate solar activity on the 



