Evening star., 1940-07-13
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Field, Laboratory
And Study
BIZ Thomas r. Henri.

ana Stuoy
By Thomas r. Henry.
"Hitler weather" is a peculiar pattern
of the upper atmosphere over Central
Europe which permits German forecast
ers to make almost perfect predictions
for week or more in advance.
This is explained by meteorologists OF
the United States Weather Bureau now
studying the dynamics of the movements
of air masses at attitudes of from 10 to
20 miles above the surface of the earth.
Such forecasts are possible, they point
out, only when special conditions obtain.
When these are found. the German
weatherman can bet his life, as he
probably actually does, that for several
days conditions will be ideal for an Of
fensive.
Perfect weather has accompanied each
of the four major German moves-Po-
land, the Low Countries, Norway and
France This has been described as
"Hitler luck" Quite to the contrary. the
meteorologists say, each move seems to
have been perfectly timed by the German
weather service. The observers wait
patiently for the development of warm
anticyclone," titanic mass Of heavy air
moving in clockwise direction. For
the first or 10 miles Of altitude the air
is heavy and relatively warm. 1t grows
warmer from day to day. This condi-
ton obtains up to the troposphere. where
temperature ceases to decline with alti-
tude. Here the atmosphere is heavy and
cold. These terms are relative. Air, of
course, is actually very light 10 miles
high and temperature is calculated by
an involved method which takes into
account what the temperature of that
air would be if it were subjected to the
pressure which obtains at the surface of
the earth.
Cold air at the surface comes from the
north. In the stratosphere, however, 1t
comes from the south, the neighborhood
Of the Equator which actually, at all
times of the year, is the coldest spot on
the planet. This seems paradoxical, but
has been generally recognized since the
start Of stratosphere observations. This
is because the stratosphere is higher in
that region. Consequently the atmos-
phere has greater distance in which to
cool off before it reaches the point where
there Is no further change with altitude.
Once this flow of air from the south Is
established at high attitudes it is almost
certain to persist for several days and
the whole pattern moves slowly west
ward. When the German meteorologists,
aided by airplane and pilot balloon OBJ
Servations, see such a condition building
up over Poland they know there will be
fair weather over France for a week,
starting a few days hence. The condi-
ton Is bound to occur several times each
year-especially in the spring, fall and
summer.
1t would be very bad luck indeed-and
almost impossible-for anything to hap
pen 10 break up such a pattern uneX-
pectedly. The condition is almost pecu-
liar to Europe. During the summer such
warm anticyclones" do build up over the
Middle West and persist for weeks at
time, but they usually are bad news"
fer they mean continued drought. In
Europe they mean the finest sort of
weather with almost cloudless skies for
the benefit of aviators and dry roads for
tanks.
Detection of such a condition in the
process of building up requires observing
stations at key points Narvik is an i'm
portant point. This was at least one rea-
son for the German eagerness to hold
this Norwegian port, American meteorol-
ogists believa Weather is as important
to Hitler as iron.
The continental warm anticyclone
pattern, however, does not obtain for
the British Isles. They are on the west
ern edge of the area affected where all
sorts of breaks in the pattern are to be
expected. They, however, have served
their purpose and fair, cloudess weather
probably would not be desirable in
launching an attack on England.
The existence of these persistent spells
of fair weather was recognized by Ger
man meteorologists in the first World
War and there was some effort at timing
offensives. But, prediction was almost
pure guesswork. There was no under
standing of the mechanics of the
stratosphere and no means of observing
conditions there. The new science, espe-
cially as it applies to Europe, originated
in Norway and has been developed large
ly by Germans and Russians.