The news scimitar. (Memphis, Tenn.) 1907-1926, 1919-04-21
SOLAR RADIATION
IS VERY VARIABLE.
Weather, With It's Changes, Is
Dependent Upon These
Diminitions of Energy

WASHINGTON, d. c.. April 81. tSpl)
The heat upon which all life on the
earth depends is radiated from the sun
through 3d. 600, 900 miles OF space. 1t
can readily be understood how changes
In the amount Of this radiation might
materially affect our weather. The
Smithsonian astrophysical observatory,
which has observing stations for study
ing the radiation from the sun in Gala
ma, Chile, and on Mount Wilson, Cali
foTnia, as well as In Washington, has
for a number of years been watching
the variations Of the solar constant"
OF radiation. Definite periods of high
and low mount OF radiation have
been found and the relation of these
periods to our temperature and wealth
er on the earth is being studied. A
sufficient number OF observations are
now available to enable tests to be
made on their value for weather pre-
diction.
Down in Bright Chile.
At Calama, Chile, in one of the most
arid regions of the globe, where the
sun shines forth from an almost cloud
less sky day after day and week after
week, and rainfall Is almost unknown,
two Smithsonian observers are record
Ing every day by mean Of delicate,
specially constructed instruments, the
amount of radiation from the sun, and
these results are te~legraphed daily to
the government Of Argentina where
they are made the basis OF tempera-
ture forecasts for several days In ad-
vance. So far the predictions have
been very promising, and when a suf-
ficiNnt length Of time has elapsed to
prove beyond a doubt the truthworthl-
ness of the method, 1t is confidently
nODe0 tina a grant rOnFnNan1nFo NJ In
torecasting weather will result. Our
own and the Brazilian weather bureaus
receive the results from Calama, but
have not yet established a Geographic
service.
Relation Varies.
These solar radiation measurements,
which are under the direction of DR..
G. G; Abbot, Of the Smithsonian In
stitution, have been made for the last
IA years at the Smithsonian observing
station on Mount Wilson, Cal, at an
altitude OF $500 feet. From these daily
observations 1t appeared that the
amount Of radiation from the sun varied
from day to day as we'll as from year
to year, showing that the sun is a
variable star having a two-fold varia-
ton: first, a long period variation due
70 sun spots and similar phenomena.
When the sun is undergoing a period
OF great activity as shown by sun spots,
prominences and similar signs, 1t is Ike
poking a fire and bringing fresh Goals
to the surface. Thus this Is produced
a hotter sun and consequently a greater
amount OF radiation. Second, there is
a short period variation which Is ex-
planned by changes in the transparency
or the outer solar envelope.
II the correlations between these vari-
atoms In the radiation from the sun
and our temperatures here on the earth
continue to prove as satisfactory as
they have up to the present in Argen-
tina, 1t will be desirable to establish
three or four additional observing sta
lions In widely separated, most cloud
less regions Of the earth, as for ex-
ample, in Australia, South Africa, In
dla and Egypt, While 1t would be de-
sirable to have these stations all under
one management, as for instance the
Smithsonian institution, the means are
not at present available, and 1t will
probably be necessary to ask the gov
ernments OF the regions noted to estab-
llsh and support their own observing
stations.