NO. 5 



SOLAR VARIATION AND FORECASTING — ABBOT 



were a meteorologist, I would not care whether the correlation was 

 through our air, through the sun, or through the star Arcturus ; I 

 would try to see whether so fair an opportunity to predict weather 

 10 days in advance could be reduced to a working basis, not only 

 in Buenos Aires but elsewhere. 



Mr. Clayton's paper describes the wealth of interesting results 

 for North America which he has lately obtained in this way. I shall 

 only give two or three examples of Argentine results. Figure 2* 

 shows the solar variation of April, 1920, observed at Calama, Chile, 



Calories 

 1.970 



1.950 



1017.3 

 1013.5 

 1009.3 



APRIL 1920 



SOLAR RADIATION Calama, Chile 



Fig. 2. — Solar variation and atmospheric pressure. Solar-constant values 

 obtained in Calama, Chile, in 1920 are compared with the atmospheric pressure 

 at three Arg-entine stations. 



and compared to the barometric pressure at Sarmiento, Patagonia. 

 Figure 3 ^ shows 3 consecutive weeks of Argentine official forecasts 

 by Mr. Clayton. Figure 4 shows 12 consecutive weeks of Argentine 

 official forecasts by Mr. Hoxmark, Mr. Clayton's successor. All of 

 these forecasts, based on solar variation, are exactly stated numerical 

 predictions of the temperature of Buenos Aires, and are compared 

 to the temperatures afterwards actually observed. The Argentine 

 official forecast is prepared each Wednesday to cover the week 

 beginning Thursday morning. Mr. Hoxmark writes that this solar 

 forecasting is based on our daily observations at Montezuma supple- 



^From Clayton's "World Weather," Macmillan Co., New York, 1923. 



