Smithsonian miscellaneous collections

SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOLUME

95 NUMBERIS

Hrtbur ^unb

FURTHER EVIDENCE ON

THE DEPENDENCE OF TERRESTRIAL TEMPERATURES ON THE ^VARIATIONS

OF SOLAR RADIATION

BY G. G.

ABBOT

Secretary, SmithsonianInstitution

(Publication 3397)

CITY

OF WASHINGTON

PUBLISHED BY

THE

SMITHSONIAN INSTITUTION

AUGUST

12,1936

I

SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOLUME

95,NUMBER15

Hrtbur jfunb

FURTHER EVIDENCE ON

THE DEPENDENCE OF TERRESTRIAL TEMPERATURES ON THE VARIATIONS

OF SOLAR RADIATION

BY G. G.

ABBOT

Secretary,SmithsonianInstitution

(Publication 3397)

GUY

OF

WASHINGTON

PUBLISHED BY

THE

SMITHSONIAN INSTITUTION

AUGUST

12,1936

BALTIMORE,MD., U.8.A.

Hrtbur jfun^

FURTHER EVIDENCE ON THE DEPENDENCE OF TERRESTRIAL TEMPERATURES ON THE

VARIATIONS OF SOLAR RADIATION

By

C. G.

abbot

Secretary, SmitJisonianInstitution

A

former paper onthis subject'

showed how

the temperatures of Washington, St. Louis,

and

Helena seem to depend on therise and

fall of solar radiation. Table i of that publication gave a series of datesinall monthsof theyear

from

theyear 1924to 1935 on which the solar radiation apparently began either to rise or to fall for a succession of several days. Infigure2 (herereproducedas figurei)

was shown

the oppositeaverage marches of temperature at

Wash-

ington for 16 days after such opposite changes of solar radiation began.

On

the basis of the evidence contained in this paper, Dr. R. A.

Millikan composed,andothers, includingDr. K.T. Compton, Dr.I.

Bowman,

andthe Chief of theUnitedStates

Weather

Bureau,signed with him, the following

memorandum

:

The workon^solarradiationthathas been carriedonfor a considerablenumber ofyearsunderthe leadershipofDoctorCharles G.Abbothas apparentlybrought to lightgoodevidence,

First,thatthe rateatwhich radiant energy comes toearthfrom the sunis notentirely constant butsometimesrisesandother times fallsthroughperiods ofanumberof days;and

Second, thatthese rising orfalling periods of solar radiation arefollowed through as muchas sixteen days by measurable temperature variations inthe atmosphereasdeterminedbyordinarythermometerreadings.

These^effectsareofsomuchscientificandpracticalinterest for theproblem ofpredictingat least someelementsof the"weather^" asmuch astwo weeks aheadthatitisourunanimous judgmentthat there should be not only a continua- tionofthisresearch but considerable enlargementandrefinementof theprogram, soasto subject these preliminaryfindings toexceedinglycarefulanddependable verificationandextension.

The Smithsonian Institution has been for atleast half a century the agent whichhasspecializedmostsuccessfully onsolar radiation problems.

No

other institutionisinasgoodapositionas isittocontinuetolead in thisfield. The

'Smithsonian Misc.Coll.,vol.95,no.12,

May

1936.

Smithsonian MiscellaneousCollections, Vol.95, No. 15 I

SMITHSONIAN MISCELLANEOUS

COLLECTIONS VOL. 95

undersignedtherefore, afteramostcarefulstudyofDr.Abbot'sprogram,endorse

itunreservedlyandexpress the earnesthopethathemayreceivetheappropria- tionsthathe needstomakeitefifective.

An

attempt

was made

toobtain aFederalappropriation of$200,000 toestablishseven additional solar-radiationstations and toundertake

MEANRESULTS1924-1935

TEMPERATURE CHANCES FOLLOAINCRISINGSOLARRADIATION

OAYSAFTERSOLAR CHANGE BEGINS SHOWN BY FULL CURVES, FALLIN6 Bv DOTTED CURVES.

NO. 15

TEMPERATURES AND

SOLAR RADIATION ABBOT

who

with the cooperation of the University of Rochester, the

Eastman Kodak

Co., and other friends will undertake tests of the automatic measurementofultravioletsolarraysathighaltitudes.

In order to

more

thoroughly buttress the proposition that solar variationisamajor factor in thetemperature changesof terrestrial

DAYS

4 SMITHSONIAN MISCELLANEOUS

COLLECTIONS VOL. 95

but allOther datesfound in Table i of

my

former publicationwere usedasdates ofincipient solarchanges.

To

obtain departures

from

approximatedailynormalsat Potsdam, the values of the daily

means

of temperature at y^, 14*', 21^ were employed.

Monthly means

of these daily

means

were available for the years 1921to 1934,inclusive.^

Average

monthlyvalueswerecom- puted for this interval and plotted on a sufficient scale.

A

smooth curve

was drawn from

these monthly averages, and the dififerences between it and the observed daily

mean

temperatures were used as temperaturedepartures.

Itisrecognizedthatthenormalsthus obtained are onlyapproximate.

But

this will not impair the value of the departures for the purpose proposed.

For

instance, if the normals thus obtained were a little

lowfor a givenmonth,the departures forallyearsduringthat

month would

be prevailinglypositive, but thecurve oftheir fhictuationover an intervalof 16days would l)e almost precisely the

same

as if the normalshad beenperfect.

Proceedingtheninexactly the

same way

asdescribedin

my

former publication, cited above,

we

arrive at the results

shown

in figure 2.

Except for the

months

of

May

and June,^ the results seemto beas emphatically favorable for

Potsdam

as for

Washington

tothe former conclusions, as follows^: Opposite changesof solarradiation are asso- ciated for at least 2 weeks after their

commencement

with opposite marchesoftemperaturedeparturesinweather.

These

averageeffects are of the order of several degrees Centigrade, although the solar changeson whichtheydependareonly of theaverage rangeofabout 0.7 percent. Ifdailyexcellent values of thesolarconstant ofradiation, trustworthy to 0.2 percent, were available, certain weather features might probablybe predicted for 2weeksor

more

inadvance. Since theoryandobservation indicate that thesolarradiation changes frac- tionallyperhapstentimes as

much

near3.too angstromsasinthesolar constant, thereisgreathopethat automatic records ofultraviolet solar radiationatgreataltitudes

may

be offirstrateimportanceforweather forecasting.

'Beob. Obs.Potsdam,Deutsch. Meteorol.Jahrb.,Teil4,Hefti.

'In thesetwo monthsconsiderabletemperaturechanges are foundat Potsdam, but theyrunparallel foropposite variationsofthesun.