NO. 5 SOLAR CONSTANT AND TEMPERATURE — ARCTOWSKI 27

9.

THE TWO ^INVERSIONS

For

Sault Ste.

Marie

the lapse rates of temperature per 1,000 m.

are recorded in table 5 for the

months

July 1939 ^to February _1941.

Only

the data

from

5

km. up

have been taken.

The

isallorhythms

show two

interruptionsin the areas of

maximum

decrease of temper- ature of

more

than 7°, the first for

March

1940, the second for

Fig. 13.

—

Temperature diflferences, July- January, 1940.

January

1941.

The

altitudesof the

maxima

of lapse ratesare highest during the

summer and

lowest during thewintermonths, respectively 8-9

and

6-7.

The

altitude of thefirstinversiongoes

from

10

up

to 13

km.

during the

months

Januaryto

May,

1940.

For

_Julyto September, _1939,

and August and

September, 1940,

no

first inversion can be distinguished, differences in plus being observed only

from

16

km.

up.

A

selection of diagrams of lapse rates simplifies comparisons. Figure _{14 gives}

3

28 SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL. lOT

Table 5. Lapse rates of temperature, Saiilt Ste. Marie

r-C ,C_^ ;>_{/ •}

^

_/

ja^ft •**

A\» ^xi" t

^> p

i> >^ ^{:> >>}

^<^^:^^x^^

^{'' ''^ ^'^}

0> J* \ W ^\N\ W ^ >l^ >)\^ _-l\\^ N^ ^ >^ :^'^ ^ ^^

Fig. 14.

—

Lapse rates oftemperature, Sault Ste. Marie.

NO. 5

SOLAR CONSTANT AND TEMPERATURE — ^ARCTOWSKI

29 those for

September

_1939, January, February,

May,

June,

and

August, 1940.

In

May

there are

two

perfectly characteristic inversions^: one at

B

with a

maximum

^of

+1.0

between ₁₃

and

14 km., the other of

+0.7

at

C

^{between i8}

and

19

km.

The

lower inversion has a well-pronounced annual variation of altitude^:

December

to

March

between 11 and 12;April, 12-13;

May,

June, July, 13-14

km.

In

August

nothing

more

than a slightinflexion of the curve of lapse rates remains between 13

and

14

km. On

^the

curve for

September

₁₉₃₉ (fig. 14) ^this inflexionis

more

accentuated (12-13)

and

still

more

(13-14) on the curves for October

and November. The

beginning of the upperinversion, C, is at 14

km.

in

December

1939,^at 17in April

and May,

at 16

June

^to October, 1940,

and

also at 16

km.

July to October, 1939.

A

comparison of the reproduced curves leads to interesting sug- gestions

on

tropospheric changes

from month

to month.

The

curve for

September

is not

what

^it shouldhave been between

4 and

⁸km., the lapseratesbeingnearlyif5 C.lessthan

on

theregular punctuated curve, with a

maximum

for 7-8.

The

curves for

May

and June

are

more

regular.

But

ⁱⁿ

August we

see again a reaction in the values of 6-y to 8-9: a tendency of tropospheric inversion.

Finally, the regular decrease of temperature

from

i

km. up

to

4 km.

on the curve for

February

is in contrast to the curve for

August

of decreasing lapse rates

up

to

4 km.

Comparing

all available data for

February

1940

we

find that the lowerinversion, properly speaking, does notextend southof

Oakland

nor south of the 36thparallel.

With

the exception of

Medford and

Oakland, of higher levels,

and

Spokane, St. Paul,

and

Sault Ste. Marie, of lower levels, all

other stations give 11-12

km.

as their characteristic increase of temperature.

The

lower level of lo-ii

km.

at

Spokane may

also be observed farther north in Fairbanks.

South

of the 36th parallel the lower inversion, properly speaking, does notexist, althoughallthecurves

show

an inflexioncorresponding to the inversion: between 11

and

12

km.

at Albuquerque,

Oklahoma

City,

and

Nashville; at 12 in Atlanta

and

Charleston;

between

12

and

13at

San

Diego, Phoenix, Pensacola,

and

very slightly at

Miami

;

while the curve of

San Antonio

also

shows

an inflexion between ₁₃ and 14

km.

In otherwords,

from

thenorth tothe souththe influence of the lower inflexion is goinghigher up.

Now,

for theuppertropopause, sodistinctly

marked on

the curveof

May

for Sault St.

Marie (C on

fig. 14), the available data suggest

an overlapping,

from

south to north,

and

its final disappearance in higher latitudes.

The

following diagrams (fig. 15) of lapse rates for

May

1940 ^are

good examples showing

the gradual disappearance of the lower in- versiongoingsouth,

from

the

Canadian

bordertotheGulf of Mexico,

or, in the southern States, going west-east

from Arizona

to Florida.

An

overlapping of the

two

tropopauses, with the upper gradually disappearing inthe north, is perfectly demonstrated

by

^this diagram.

To sum

up:

we must make

a distinction

between two

types of stratosphere

—

the stratosphere of tropical regions, above 19

km.

of altitude,

and

the stratosphere of high latitudes, extending

down

to 10 or

9 km.

^{in Alaska.}

They

overlap in the United States

where

a distinction

between

alower

and

an upperstratosphereshould be made.

Fig. 15.

—

^Lapse rates for

May

1940.

In a studyof theannualvariationsof temperature over

Lindenberg

a substratosphere (the pseudo-stratosphere of Jaumotte) has been admitted

by

_J.

Reger

and, before him,

by Schmauss^'

but

nowhere

in

Europe

do the

monthly mean

data give such convincing informa- tion

on

the coexistence of an

upper and

a lower tropopause as

do

those of the

American

^stations.

Then,

for the troposphere, a distinction between high

and

low altitudes should also be

made,

best perhaps for the altitudes above

and

below the levels of the highest lapse rates. Finally, in the lower troposphere the individuality of

an

active bottom zone, of the

most

frequent inversions, should perhaps also be recognized. This active troposphere is continental. It does not extend over the Atlantic.

^^Schmauss, A., Die Substraposphare. Beitr. Phys. Freien Atmosph., vol. 6, p. 153, 1914-