Evening star., 1932-04-27
CLIMATIC CYCLES
DEBATED At FINAL
SCIENCE SESSION
Experts Ponder Whether
Ages, Like Years, Have
Recurring Seasons.
SYMPOSIUM CONDUCTED
BY DR.. JOHN c. MERRIAM
DR.. Abbott Describes 40 Study
of Variation in Daily Amount
of Radiation.
BY THOMAS r. HENRY.

BY THOMAS R. HENRY.
Whether ages, like years, have their
recurring seasons was debated at the
closing session of the National Acad-
emy of Sciences yesterday.
DR.. John c. Merriam, president OF
the Carnegie Institution of washington,
conducted a symposium on climatic
cycles. Because of the great cbmplexity
of factors involved, it was explained,
this is one of the most intricate prob
lens now before the world of science.
Dr. A. E. Douglass of the University
of Arizona told of an investigation now
under way to determine the existence
of regularly recurring periods in the
growth Of the giant sequoias of Cali
fornia. Each year Of trees life a
ring is formed in the wood. The width
of this ring indicates the amount of
growth during the year in which it was
formed. Other things being equal, it
depends on the amount of rainfall.
Old Records Traced.
said, go back without break for 5000
years. The width of the rings. he
finds, does vary in a periodic fash
ion, although it is very complicated.
The progression is roughly in accord
with the sun-Spot cycle of about IL
years-that is, the tree growth cycles
are fraction of small multiples" of
this period. The disturbances on the
face of the sun known as sun spots
pass through maximum and minimum
phase during the 11-year cycle and
in some intricate way this seems to be
reflected in the temperature and rain
fall on earth.
DR.. Charles G. Abbott, secretary of
tho CroithcOpioY1 TnctitIrti0r told of ~
40-year study of variations in the daily
amount of radiation received by the
earth from the sun-upon which all
life on earth depends. He has found
partly through use of a new mathe-
mtical machine of his own invention
which was exhibited at the academy
meeting-seven periodicities in this
solar radiation. These in turn are
closely related to the sun-spot period.
After establishing these periodicities,
Dr. Abbot said, he analyzed in the
same way the temperature records over
a number of years for Washington
and for stations in North Dakota and
Alabama.
PrOgressions Regular.
He found that at all three places
tha temperatur, variations followed
fairly regular progressions and that the
CulbCo OUidSllSQ 4OI tllc pdII WCLC
very close to the solar radiation curve.
This, he said, was evidence that solar
radiation variations constituted the
chief factor in temperature variations
when the annual seasonal effect was
eliminated. But, while pronounced, the
effect was sometimes opposite for diff
ferent places and seasons.
Through the establishment of such
relationships, DR.. Abbot said, the pos
Ill, Is 49, -
forecasttng has become better estab-
hshed. AS test DR.. Abbot reversed
the ordinary procedure and made
long-range forecast backward from
1928 to 1916. The trouble with
long-range forecast into the future is
that the world must wait for its veri-
fication
Using only his solar radiation curves,
DR.. Abbot predicted what the weather
had been and then checked up with
the actual climatic records for the
while not altogether accurate, was
much better than could have been
obtained from chance and actually was
better than he expected.
The sun spots themselves, said Dr. W.
8. Adams, director of the Mount Wilson
Observatory, are the result Of some
thing deep-Seated in the sun itself.
Spectrum studies Of the regions on the
suns surface near these spots, recently
conducted at Mount Wilson, show that
they are radiating abnormally. There
Is a fairly close relationship, he said.
between the appearance of bomblike
projections from the face Of the sun
and magnetic storms in the earth's
atmosphere. There is also a relation
ship between the sun spots and the
amount Of ultraviolet radiation re-
ceived on earth.
Vary During Cycle.
ut seems probable" DR.. Adams said,
shat both the quantity and quality of
solar radiation vary during the sun
spot cycle and definite correlations have
been found with the variations of ter
restrial magnetism and its related phe-
nomena. There is evidence of a slight
correlation between sun spots and
atmospheric temperature in certain
regions of the earth and with other
factors Of weather and climate for lin
tied regions and for limited time
intervals. These correlations are so
uncertain that, in the majority of cases
at least, predictions based en- them have
very little weight"
1t may be possible to check the tree
ring record by study of the lake-f1oor
deposits of the Great Basin region, said
DR.. Isaiah Bowman of the American
Geographical Society. The sediment
deposited on lake floor in Summer is
different In color from that deposited
IN Winter. so that banded effect re-
suits.
The amount of sediment is Influenced
by the relative wetneSs of the season.
Thus record dating back for many
years can be obtained. In this case it
would be especially valuable as a check
on DR.. Douglass sequoia records, OBJ
tanned from the same locality. 1t may
also prove possible he said, to correlate
the expansion and contraction of the