Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-09-07

the degree to which his prediction is verified"
heard that it might be done through study of
ocean temperature" I suggested
mo one has been able to do it yet" answer
ed Prof Marvin. THE conditions prevailing in
or on an ocean adjoining q continent affect the.
land weather If the atmosphere moves from the
ocean over the land. Cur prevailing winds
move eastward and the Atlantic does not
seriously influence our weather. The Pacific
does influence the weather of the West Coast
States and our forecasters make considerable
use OF ocean temperatures. reported by wireless
from ships at sea, i'm making their forecasts
for the far-weStern country. But we find
scientific basis in this for attempting yearly
seasonal forecasts"
Sun spots and variations in the solar constant
have been proposed as bases for l0ng-range
weather forecaSting. What does the weather
chief think OF them?
"Of course. the power behind all our
weather is the sum-" he answered. '"The solar
radiation Is the energy that drives the gigantic
atmospheric engine which grinds out our
weather. But precisely what the intricate rela-
tiOnships are between the central power house
90. 100000 miles away and this whirling, eddy
ing, ever-changing ocean Of air, at the bottom OF
which we set UP our measuring instruments,
is still much of q mystery.
THE difflculty in trying to trace q connec-
ton between sun spots and terrestrial weather is
ennpnaSlzeu Dy the lack Oh uHuUfHuLby IA cuSCto.
It will be raining in one region, unusually dry
in another, colder than average somewhere else
and normal over other regions simultaneously,
while sun spots are passing across the solar
fIce. II they were the key to our weather,
surely sun spots would affect the whole earth
in a consistent way
quite a. different thing from the sun-spOt
cycle is the variation in solar constant Of radia-
ton reported by the Smithsonian Institution,
and some have attempted to. forecast the
weather for weeks and even months in advance
on the strength of it. But the changes re-
ported are very slight-only one-fourth Of
per cent,-and the effect that this variation
9SOO0OO0 miles away may have ON the move
ments of air currents. down at the bottom OF
our atmosphere is surely SO slight as 10 be
negligible:
ut is the 90aE per cent OF sunlight that foods
interplanetary space unchanged; IL Is this
gross energy, and not the deduction or addi-
ton of the minute one-fonrth of per cent
that counts. 1 do not know of any predictions
based on variations Of the solar constant or ON
sun-spot cycles which qualify verified"
It is true, however, pointed out Prof. Marvin.
that slow progressive changes are under way
in the solar system which affect the earth. Be-
cause our path around the sun is not circular
but oval, the distance between the earth and
the sun varies from day to day. Astronomical
measurements show that we are closest to the
Sun-that Is, at perihelion-around january 1.
We are 3,l07000 miles nearer the sun then
than we are in July, when. the earth is faEthest
from its star.
CERTAIN complications in the motion OF the.
earth with respect to the sun are causing
the date, for this position to advance in time