NO. 3 SIXTY-YEAR WEATHER FORECASTS — ABBOT 3 



vapor and dust, profoundly modify weather. He cites the first four 

 cases in the following list, and I add several more. 



Approximate 



dates Eruptions 



1856 Cotopaxi and others. 



1883-1890 Krakatoa and others. 



1901-1904 Pele, Santa Maria, Colima, and others. 



1912 Katmai. 



1924 and 1928 Many great eruptions. 



1930 Great eruptions. 



1947 Niuafoo Island. 



10. Of 30 unsatisfactory years, in lOO years of synthesis of St. Louis 

 precipitation, these lie in groups as follows: 1854 first half; 1856 to 

 i860; 1887 to 1889; 1900; 1901; 1905 to 1907; 1912 last half, 1913 

 first half; 191 5 to 191 7; 1920; 1923 to 1926; 1930; 1940 to 1950. It 

 will be seen that almost all these unsatisfactory intervals fall either 

 when tremendous volcanic eruptions occurred or when there was tre- 

 mendous use of explosives in war or explosions of atomic bombs. As 

 will be pointed out in Part 2, atmospheric changes alter the lags in 

 the weather effects of all solar impulses, and of course unequal periods 

 have unequal lags. These unusual atmospheric disturbances may very 

 well have mixed up the terrestrial responses to the 23 periods so as 

 to cause the events to differ from the predictions. 



With these propositions stated, I go on to present evidences justify- 

 ing my claims. 



Figure i is a reproduction of an actual synthesis, made to deter- 

 mine the march of precipitation at St. Louis, Mo., over the five years 

 1875 to 1879 inclusive. Its 22 columns of precipitation departures are 

 in percentages of normal, expressed in tenths of a percent, and are 

 mean values of the periodic percentage departures derived from 1,032 

 months and meticulously arranged with regard to phases. The 22 

 periods used in St. Louis precipitation are shown in table i. 



Table i. — Periods used in St. Louis syntheses, in months 



No I 2 3 4 s 6 7 8 9 10 II 



Period 4-1/3 5-1/8 6-1/15 7 8-i/8 9-1/6 9-3/4 lo-i/io 10-6/10 11-1/5 13-1/10 



No 12 13 14 15 -16 17 18 19 20 21 22 



Period 13-6/10 15-1/6 22-4/5 24-4/s 30-1/3 34-i/5 38-8/10 45-1/2 27-1/48 68-1/2 91 



In some other syntheses a period of 19^ months was found to be 

 overriding the period of 38?io months. In some, the period of 54^ 

 months was strong, and its half, 27^ months, unimportant. 



3 It was found that 542 months gave no appreciable departures when relieved 

 of the overriding period of ^-^^=27^ months. 



