NO. 6 



MAGNETIC STORMS — ABBOT 



relatively minor effects of the invasion of ions, at times of magnetic 

 storms, are superposed on large variations of sky brightness due to 

 other causes. 



120 



no 



100 



Fig. 3. — Increased skj- brightness after severe magnetic storms. Abscissae, 

 days before and after height of storm; ordinates, pyranometcr observations of 

 sky brightness. 



Table 2. — Effect of mognctic storms on sky bright>ucss. Pyranometcr observations 



Days from lero day — 10 — 9 — 8 — 7 — 6 —5 — 4 —3 —2 — i 0123456789 10 



Vo. of observations 19 19 19 21 24 21 19 24 23 23 23 22 19 24 22 23 23 19 19 21 19 



klean pyranometcr 102 104 124 loi 112 115 106 105 no loS 118 127 119 114 112 127 120 118 107 121 134 



Mean of first 10 = 109 Mean of last 10 = 119 



MAGNETIC STORMS AND WASHINGTON TEMPERATURE 



It remains to trace the effects of ionic bombardment on temperature 

 at the earth's surface. The departures from normal temperatures at 

 Washington from 9 days before zeroth day to 9 days after have been 

 tabulated for 73 severe magnetic storms occurring from 1923 to 1946. 

 In this tabulation no vacancies occurred in the sequences. Hence I 

 give only the mean results in table 3 and figure 4. 



Washington temperature fell sharply, beginning i day before the 

 magnetic storm, and reaching a level on storm day 3° below that of 

 the mean of temperatures from 9 to 2 days before the storm. After 

 the storm the temj^erature rose sharply, but averaged 0.8° lower from 

 tiie second to the ninth day after the stonn than the mean value 

 before it. 



