NO. 6 



SOLAR RADIATION AND WEATHER CLAYTON 



7 



marked "A" shows the day of the high values, and " B," " C," etc., 

 show succeeding" maxima of solar radiation disclosed by the mean 

 results. It is seen that the succeeding maxima are reflected in the 

 mean observed temperatures at Buenos Aires for the same days and 

 probably cause them, since, omitting the solar maximum "A," the 

 succeeding solar changes and the following temperature changes at 

 Buenos Aires show a minus correlation of 0.66 for the 30 days. 

 In the plot in figure 4 the temperature is inverted, that is, high 

 values are plotted downward and displaced 3 days to allow for lag 

 in temperature changes. 



5 DAYS 10 15 20 25 50 



Fig. 4.- — Mean values of solar radiation and of temperature at Buenos 

 Aires preceding and following maxima of solar radiation, 1909-1918. 

 (i) Mean values of solar radiation preceding and following maxima above 

 1.990 calories. (2) Mean temperatures in Buenos Aires 3 days later 

 (inverted). 



The contrast between the mean pressures foimd with low values 

 of solar radiation and with high values is shown in figures 5 to 7. 

 The mean difference between the pressure accompanying low solar 

 values and that accompanying high values on the day of observation is 

 shown by the upper chart in figure 5 to exceed .08 of an inch with the 

 high pressure central near the middle of the North American con- 

 tinent on the eastern Rocky Mountain slope. This high pressure area 

 on succeeding days drifts eastward as shown by the lower charts in 

 figure 5 and the charts in figure 6. Three days after the day of the 

 solar observation it passes ofif the east coast of the United States. It is 

 followed by a low pressure which forms at a lower latitude and in 

 turn drifts eastward to the Atlantic coast. This change of latitude 

 with decreasing radiation has significance as will be seen later. 



