82 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 94

NO. 10 SOLAR RADIATION

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rORECAST- OBSERVLD

Fig. 37.

—

Eleven-year forecastsfor Vienna, Austria, and North Platte, Nebr., withverifications. Forecastsmade stepbystep.

84

SMITHSONIAN MISCELLANEOUS

COLLECTIONS VOL. 94 ofweather. Thesearefoundtooccurat integralmultiples of ii^ years measured

from

January 1819.

These phenomena, ifaccepted asfactsof Nature,propoundedtous several problems

:

A.

Why

should the sun, agaseous body, emitcomplex pulsations of radiationwhichare of thenature of afundamental and 1 1 or

more

overtones?

A

violin string

may

do ^this, but

why

should a gaseous sphere?

B.

Why

should the terrestrial responses to these pulsations

show

changesof phase, form, and amplitudeat intervalsintimately related to thefundamental period of23^years?

C.

Are

the terrestrialresponses of an order of magnitude reason- ably corresponding to the solarimpulses?

For

questionA,IconfessthatIhave nosuggestionto offer. Imust leaveitssolutiontothosetheorists

who may

beconvincedbysectionT ofthispaperthatthereisarealbodyoffactswhich provethe existence of complexsolar variation.

As

for question B, themostnatural hypothesisistoassumethatthe phases and amplitudes of the solar periodicities themselves change

from

time to time at intervals related to 117 ^years. Solar-constant observations are not yet of longenoughstandingtoverifythis. Ihave thereforesoughtto find

some

helping clueina regularity of behavior regarding changes ofphase

among

thedifferent stations. In this in- quiry I have

compared

the changes

shown

by the 8-, 11-, 21-, 25-, and 68-monthperiodicities intemperatureaspresentedbythevarious stations Berlin, Copenhagen, Helsingfors, Greenwich,

Cape Town,

andAdelaide.Itseemedsuperfluoustoexaminethe precipitation which, as meteorologists areaware,is looselydependenton temperature.

Ihavedevised asortof shorthand adaptedtoexhibit theresultsof this comparison. It is

shown

in figure 38.

At

theleft of each sub- figure willbe found theapproximatedates of beginningand end of each ii^-yearintervalforwhichtabularcomputationsofperiodicities were made.

Under

the

names

of the stations appear symbols which are designed to represent the types of curves found during the various intervals of 11^ years. These symbols are five in number, but

may

becombinedto indicate thatthe firsthalf of a curve is of onetype,andthesecondhalfof another.

The

symbolsareas follows:

Numbers

i and 2 are vertical and horizontal lines.

They

represent invertedphasesofcurves ofapproximatelythe

same

form.

Numbers

3and 4^{arelinesinclinedat}45° respectivelytotheleftandtheright.

They

also represent inverted phases of curves of approximatelythe

same

form, but of a

form

essentially differing

from

thatrepresented

NO. 10 SOLAR RADIATION

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85

86 SMITHSONIAN MISCELLANEOUS

COLLECTIONS VOL. 94 by symbols iand2.

Number

5^isa zigzagline. Itrepresentsaninde- terminate

form

of curve not similar tothose representedby i, 2, 3,

and4. Itisnot intendedto implythatcurves i and2 or 3and 4^are alwayssimilarin

form

asbetween representations ofperiodicities of different stationsorperiodicities of different lengths. It is only im- pliedthat allcurves i and 2 within a single vertical column of the

same

subfigure are approximately similar though inverted, and all those represented as 3and 4 within a single vertical column of the

same

subfigure areapproximatelysimilarthough^inverted.

Owing

to local influences, it

was

not tobeexpected thatcomplete

harmony would

prevail throughout all the subfigures.

But

if the changes of phaseand

form

in terrestrial periodicities to which ex- tendedreferences have been made,are dueto radical changes in the solar radiation,it

would

naturallybeexpectedthat similar mutations ofphase and

form

wouldtendto occur inallterrestrial periodicities andallstations at aboutthe

same

time.

Figure 38 seemsto

show

thatonthewholethisexpectationis fairly supportedbythefacts.

Though

exceptions occur, thereisa prevailing tendency for inversions to occur in all periodicities and all stations simultaneously. Thus, for illustration,at the years 1841, 1864, and

1910, reversals or at least majormodifications of

form

occurredin nearlyall cases,and this also frequently happenedat theyear 1887.

Itisbelieved that the exceptions are neither

more numerous

nor

more

radical than might fairly be attributed to local terrestrial influences affecting conditionsdifferently atthese widely separatedstations.

Ifthisconclusionissound, modifications

may

^wellbeexpected

from

theprediction I have venturedof solar variation for the years 1935, 1936. and 1937 ^{as given in figure} 7.

For

on that basis it is very probable that a radical change in the phases or amplitudes of solar variation,or inboth, willhaveoccurred about 1934, being 115 years after 1819,andwillgreatlymodifysolarvariationinsubsequentyears.

Butyetthisresultmightnot occur, foratseveralepochstheterrestrial periodicities appear to havecontinued stability for23 years or even longer,which mightcallfor asimilarlylong-livedstability inthesolar variation,and no mutation ^ofit in1934.

As

forthe third query, C,letusrestrictourinvestigationtothein- terval 1920-

1930, for^it isonly thenthat

we

have actualobservations of the amplitudes of the periodicities, both of thesolarradiationand theterrestrial temperature. Intable 13 I give theamplitudes of the periodicities expressed in percentages of the solar constant (1.94 calories per square centimeter per minute) and in percentages of the absolutetemperatureof theearth,whichItakeas290°Centigrade.

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87

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0\•*ro•*00 -r

2

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