NO. 6 



SOLAR RADIATION AND WEATHER CLAYTON 



35 



Figure 29 shows the distribution of pressure in July, 1905, with 

 the mean solar radiation i per cent above normal. The areas of excess 

 pressure are again over the great oceans, and there is a defect of pres- 

 sure over the northern continents and over the tropical parts of 

 Africa and South America. The greatest departures are now found, 

 in general, between the 40th and 50th parallel. In North America and 

 the North Atlantic, this position is some 20° of latitude south of that 

 in 1917. In the equatorial belt the pressure averages below normal, 

 although there is some protrusion of the excess areas of high latitudes 

 into the belt. 



Solar radiation one percent above normal — July 1905, 



Fig. 29. 



Figure 30 shows the departures from normal pressure in July, 1913, 

 with the solar radiation i per cent below normal. Areas of defective 

 pressure now appear over the Pacific and North Atlantic, while there 

 is a belt of excess pressure covering most of the equatorial zone 

 between 40° N. and 30° S. The maximum departures are, in gen- 

 eral, between 20° and 30° North and South, that is, about 20° of 

 latitude south of their position in 1905, while a second series of 

 maxima appear over northern Europe and Asia. The belt of low 

 pressure around the poles in the southern hemisphere is nearer 

 the equator than normal, and it is probable that there was an excess 

 of pressure over the Antarctic. 



Figure 31 shows the departures from normal pressure in July, 

 1910, when the solar radiation was 2 per cent below normal. The 



