Evening star., 1951-02-07
Jet Stream Wind Found
World Weather Factor
Funtostic Stories Of Pilots
Hiqh Over Guam Verified
By Thomos r. Henry

Discovery of phenomenon which may
be an important factor in the worlds
weather has been announced by Univer-
sity of Chicago n1eteorologists. This Is
the Jet stream, wind Of $50 miles an
hour or more, blowing at high attitudes.
The existence of these jet streams was
discovered during the closing months Of
World War II when bomber pilots out
of Guam and Saipan reported their
planes bucking fantastic west winds at
high-level fight. Their stories were
received with considerable doubt, espe-
cially when they reported one burst Of
wind strong enough to blow the plane
backward while over target.
After the war the reports were taken
up by three University of Chicago SCI
entists. The group, headed by DR.. Carl
Gustaf Rossby. found the stories almost
entirely confirmed.
Concentrated Current.
A jet stream is a concentrated wind
current existing between 10000 and
10000 feet above ground level It gets
its name because the wind does not
prevail in broad belt but rather is con-
centrated like jet of air. The streams
are most prominent in middle latitudes,
such as over the United States.
A Jet stream affects ground weather
because it changes the pattern of lower
air movements. Especially, 1t can cause
lower air to rise. As this air rises 1t
expands, cools: and its moisture con-
denses in the form of rainfall. Vertical
air movements also result in horizontal
air displacements on the earth's surface
which can manifest themselves in low
pressure areas, storms and cyclones.
The behavior of such jet stream is
recorded by special balloons which rise
to the appropriate heights and auto
matically radio" their observations back
to earth. Already Sweden and Canada
are taking this data into consideration
in weather forecasts and the United
States Weather Bureau is using, it as
one element in fiye-day forecasts.
Fitting of more than 100 prehistoric
dates-ranging from those of the tombs
of Egyptian kings to those Of some Of
the earliest human occupation sites in
the New World-into the new radio
carbon calendar Of history during the
past 18 months has been reported to the
American Association for the Advance
ment of Science.
The work reported was done by J. r.
Arnold and w. F. Libby Of the Univer-
sity Of Chicago's Institute for Nuclear
Studies and represents the most striking
advance yet reported in this method Of
checking on pre-history.
Nitrogen bombarded by cosmic rays In
the upper atmosphere Is transmitted into
form of exploding carbon. This mixes
with the air and is Incorporated in the
bodies Of all living things. It disappears
through dlsintegration, half of any
amount originally present being lost In
approximately $50 years. The amount
present is fair measure of the age Of
remains of any living thing.
Some Of the most important time
determinations now reported are Of
Egyptian antiquities, the date of some
of which were known from history with
fair accuracy. In nearly every case the
radiocarbon clock checked very well.
Example Cited. sasa
3 For example, it is known from fairly
good records that the funeral Of Phar-
aoh Sesostris III took place $3.50 years
ago. The new determinations place IL
at approximately 3.621 years ago, with
possible error of 180 years In either
direction. This was calculated from
the radiocarbon content in the wood Of
the emperor's funeral ship.
Barley seeds from predynastic Egyp-
tian house proved to be approximately
5000 years old.
Many Of the dates of New World
material measured by the radiocarbon
disintegration method concern the time
of the last ice advance over the con-
tinent. This appears to have been ap-
proximately $4,000 years ago. It is
deduced from the remains of trees obvi-
ously pushed over by the advancing ice.
The oldest New World human artifacts
measured date back about 5000 years.