Evening star., 1932-06-02
8 WEATHER CYCLES
DISCOVERED HERE
Dr.. Charles G. Abbot An
nounces Findings in Tenn
perature Changes.

Discovery of eight cycles in the
climate of Washington was announced
today by DR.. Charles G. Abbot, Secre-
tary of the Smithsonian Institution.
These cycles are mutually independ-
ent periodicities in monthly tempera-
ture departures from 12-year means
found in the U. S. Weather Bureau rec
ords between 1918 and 1880. The dis
covery was made possible by the
periodometer, mathematical machine
recently perfected by DR.. Abbot. Ex-
ceptional skill in the manipulation of
this machine has been acquired in a
few months by DR.. Abbot's assistant,
Mrs. A. M Bond. making possible the
rapid analysis of the enormous amount
Of data involved.
Cycle Explained.
The meaning of a climatic cycle, it
is explained in a Smithsonian report OF
the discovery, can be made clear from
a comparison with the l2-month calen-
dar year The year, as it is manifested
climatically, can be described as a l2-
month periodicity of departures from
the mean. Considering this mean
the average of all the temperatures for
the 365 days-aS straight line, Sum-
mer and Winter would be indicated by
departures above and below the line.
Dr. Abbott first removed from the
data this well known yearly range OF
temperatures and then found the ad-
ditional hidden periodicities in the re-
sidual monthly temperature departures
for the IL years. He analyZed the
records for the District of Columbia
Clanton, Ala, and Williston, N. Oak
The eight hidden cycles found in the
Washington temperatures consisted re
spectively of 8, 912, 1872, ID, 25, 40, %
and 135 months. They ran consist
emily through the IA months analysed
by the machine.
Comparison of Records.
Ten such periodicities ran through
the Alabama records. The 1872 period
found in Washington was not found in
the Southern station. The records die
show cyclic departures of 2l, "a and SO
months which could not be detected
in the climate of the National Capital
The North Dakota station showed ii OF
the hidden cycles. 1t dropped out the
9 month period common to Alabama
and Washington and the "a and 80
month periods of the southern sta
ton. 1t kept all the others and added
Z and % month periodicities not shown
at Clanton or Washington.
For all three stations a total OF IA
cycles was found. These temperature
departure periodicities, DR.. Abbot ex-
plains, fall into two classes. Eight, out
of the total of IA, correspond ex-
actly to periodicities in the radiation
output of the sun. The relationship,
both as to time interval and amount
of departure is so close as to indicate
tI1t fio1 nh
non is directly dependent on the solar
change.
Measurement Perfected.
The measurement of solar radiation
upon which all life on earth depends,
has been a major line of research OF
DR.. Abbot and the Smithsonian Insti-
tuition for years. With observatories in
widely separated parts of the earth, the
technique of this difficult measurement
has been perfected so that the probable
error is less than one-tenth of l per
cent.
The solar radiation is expressed in
terms of the solar constant, or the
average amount of heat that would be
absorbed in minute by cubic cent?
meter of some perfect absorbing me-
dium placed at the outer limit Of the
earth's atmosphere. This amounts to
1.e4 calories. The periodicities are
manifested by regularly recurring Sc
quences of departure from this stand
ard solar constant.
The 8, Is, As. 63 and 1876 month
weather cycles in the District OF Co.
lumbia, DR.. Abbot's data show, are
closely tied up with almost identical
solar radiation cycles. The 91,. 13k
and 18 month cycles in the District
records 90 not appear to be related tc
anything happening on the sun. They
apparently are due to some periodic
terrestrial phenomenon, and at present
no explanation can be offered for them
Some of the sun cycles appear tt
drop out altogether in the Washington
variations. There Is one, for example