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METEOROLOGY 



Possibly the most important IGY contribution to meteorology was 

 the study of Antarctic weather. Old theories of air circulation were 

 disproved, and fundamental contrasts with northern polar weather 

 were made possible. In particular, it was found that the Antarctic 

 continent did not, as previously thought, impede the free flow of 

 tropospheric winds across it, distributing heat and moisture and 

 greatly slowing temperature drops during the polar night. Rather, 

 stratospheric air masses were found to be contained by a strong jet 

 stream which encircles the continent and Causes continuously dropping 

 temperatures in the winter. Much of what was learned during tnese 

 IGY studies should assist in developing better weather prediction 

 capabilities, as well as contributing to long-range efforts to exercise 

 some degree of control over the earth's weather. 



NUCLEAR RADIATION 



IGY experiments confirmed the fact that atomic bursts in iono- 

 spheric regions can produce artificial radiation and other widespread 

 effects similar to those produced by nature. By exploding small 

 nuclear devices between tne Van Allen radiation belts, the scientists 

 injected a known quantity of electrons of known energies into the 

 earth's magnetic field at known times and places, thus producing 

 artificial auroral luminescence. These experiments represented the 

 first time in history that worldwide synoptical measurements were 

 made on a completely controlled geophysical phenomenon. 



OCEANOGRAPHY 



Studies of ocean currents demonstrated that the ocean depths are 

 very much in motion. The discovery that movements were much 

 greater than those necessary to compensate for windblown currents on 

 the surface led to the conclusion that thermal forces are primarily 

 responsible for the massive circulation of ocean water. Three major 

 countercurrents — one in the Atlantic flowing deep beneath the Gulf 

 Stream, and two in the Pacific — were located, clocked, and measured. 

 Studies of the deep ocean trenches of the Pacific showed that life, 

 including fish, crustaceans, and fauna, exists even under conditions 

 almost 40,000 feet below the surface. Also, it was shown that, contrary 

 to previous belief, the water of deep ocean trenches is not stagnant, 

 and hence it was demonstrated that such trenches are unsuitable for 

 dumping of radioactive wastes. 



SEISMOLOGY 



The IGY afforded unique opportunities to place seismographic 

 recorders in remote parts of tne world, particularly in the polar 

 regions. Antarctic observations were especially useful in obtaining 

 valuable readings on a broad range of far-southern quakes covering a 

 vast area, and for helping to determine propagation velocities through 

 ocean crustal formations. Reflected waves from small surface explo- 

 sions were used to determine subsurface structure, disclosing the ice 



