IGY IN RETROSPECT—ROBERTS PAW 
time it became possible to compile reasonably detailed pole-to-pole 
cross sections and synoptic charts. This was achieved by the estab- 
lishment of three standard meridians—10° and 140° E, and 70° W— 
along which the participating nations concentrated their observing 
stations; by the opening of Antarctica to observation; and by a gen- 
eral intensification of station layouts everywhere. ‘These improve- 
ments in coverage, and the relentless penetration of the stratosphere 
by soundings to new heights, are rapidly advancing the state of 
scientific meteorology. 
Perhaps the most important IGY contribution to meteorology was 
the weather study of Antarctica. That bleak land has the world’s 
coldest weather—a low temperature of 125.3° F. below zero is on 
record—but not all of Antarctica is that cold. Differences in the 
winter temperatures of portions of the continent equa] those between 
Miami, Fla., and the Arctic. Old incorrect theories of the air circula- 
tion were laid at rest, and fundamental contrasts with northern polar 
weather were found. 
The intensely cold air reaches perhaps only 1 kilometer above the 
ground; at greater heights the readings range 50° and more upward. 
It is accordingly believed that the Antarctic is not the major reason 
for the generally colder climate of the Southern Hemisphere. There 
are marked seasonal fluctuations of the stratosphere within a range 
as great as 150° F., a circumstance of high significance in the study 
of widespread climatic processes. The Antarctic stratospheric cy- 
clone, unlike its mobile Arctic counterpart, tends to linger near the 
South Pole. 
Air circulation is one of the main ingredients of the picture. It is 
now known that the Antarctic Continent presents no barrier to the 
free flow of tropospheric winds clear across the continent, distributing 
heat and moisture and greatly slowing the temperature fall during 
the polar night. In contrast, the stratospheric airmasses appear to 
be sealed off by a strong jet stream encircling the continent; thus its 
temperature drops continuously in the winter. 
Important help in the exploration of upper air movements was 
afforded by modern balloon-borne radiosondes capable of reaching 
great heights. Natural radioactive tracer elements, such as tritium, 
also provided valuable clues. Worldwide circulation patterns exist. 
It was found that multiple jet streams at 9 to 12 kilometers exist even 
in high latitudes. Aside from research value, such information has 
already facilitated high-level jet-aircraft operations. 
A great deal of investigation was carried out to determine atmos- 
pheric temperatures and the content of water and other compounds 
such as carbon dioxide and ozone, which have significant parts in the 
general mechanics of weather. The oceans, source of most of the 
