24 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IIO 



The Average Behaviour of the Absolute Topography of the 

 500 mb - Surface as related to all (51 ) very Intense Ultraviolet 



Radiation - Invasions (between 0900 and I500 GMT ) which were not preceded on 

 the previous 5 Days by equolly strong Invasions. 



Average Change in dl<m from the 

 Preceding Day to the InvOSJOn - Day 







Summer 



(April - Sapl.l 



fee -194 



AIM Seasons 



- 194 



Winter 



(Oct- Morch) 



- 194 



Average Change in dkm from the Preceding Day 



to the Day vtfhich follows the Invasior 



Fig. 19. 



