Evening star., 1925-07-16
Study
!. OF WEATHER FULL
Reports From Entire North
/; Hemisphere Gave Fly
I: ers Data.
BY PROF. JACOB BJERKNEs.

= BY PROF. JACOB BJERkNES.
Chief Meteorologist of the Amundsen-Er
ID worth Expedition.
.,OSLo, July 16.-The intensive study
sof weather probabilities has been car
Sied to a new stage in polar explora-
Sion by the Amundsen- Ellsworth ex-
Sedition. Our charts of meteorologi-
sal conditions were based on wireless
aAformation received several times
daily from more than 200 points COW
FIRING the entire northern hemisphere
bf the globe. This made it possible
se render polar exploration more
4learly foolproof than ever before in
fAstory, with exact scientific predic,
lions based on accurate worldwide
observations instantaneously received
md Immediately charted.
L have several hundred INQUIRIES
from persons interested in the science
Pf weather prediction asking for de-
dails of our work at Spitzbergen.
Many of these inquiries came from
america, and because it is physically
Impossible to reply to them individual
", L have set down the data which
dhey desire in a form as simple as
she technical nature of the subject
permits, for publication by The Star
and its allied newspapers. The most
favorable conditions for the polar
flight demanded a light breeze, a
Sloudless sky and a probability that
these conditions would continue for a
seriod of several days. In order to
Secure these conditions. we had to
await until a high-pressure atnos-
pheric system extended over the
&vhole area from Spitzbergen to the
Pole.
=. Charts Cover Hemisphere.
The first time this occurred was on
May 4, just as the flying machine had
been put together in readiness for the
Rtart. On the accompanying chart
Gig. u an anti-cyclone will be seen
pyer the polar region, surrounded by
q. fringe of low pressure, with the
chief storm centers over Ireland and
north Norway, besides three in north
Prn Siberia and one over Arctic Can
ada. These charts cover the entire
Northern Hemisphere.
This favorable distribution did not
last, however. The low pressure over
Norway extended rapidly, travelling in
q. northeasterly direction and thrust
ing the polar high pressure aside to-
ward Greenland.
9 sOn May s, when the final prepara-
ions were almost complete, the low
pressure had moved so near the Pole
fhat 1t was deemed inadviSable to at
Sempt the flight. This decision was,
Furthermore, strengthened by local
weather conditions on the north coast
of Spitzbergen. The northeast wind,
Which prevailed from May onward,
AS a fine weather wind both for the
polar ice and for west Spitzbergen, but
not for the north coast, where it
drives the air up the mountain slopes,
blaking the weather cloudy and rem
dering the visibility very poor for
flying.
., Easterly Wind Needed
! In order to secure fine weather on
the west and north coasts simulta-
heously, the wind should be easterly
or northeasterly. But long time
Elapsed before we got this. Westerly
Blinds with overcast weather prevailed
Entil May IS, when a change set in.
A,powerful storm center passing Bear
ISLAND caused the wind to veer to east
IN Spitzbergen, and the storm was fol
lowed by an anti-cyclone from Labra-
ilor which crossed Greenland and
hioved on toward the pole. The wind
Eas still too high and the visibility
Dyer Spitzbergen was not perfect, but
there seemed to be a good prospect of
fne weather for flying in two or three
days time. Consequently the ma
Chimes were made ready to start at a
moments notice.
Three more days elapsed before the
Weather conditions became entirely
Suitable for the flight (see Fig. y
She anti-cyclone had long since spread
OYer the Polar Sea, and the stormy
Steather which had passed Bear Island
had Travelled on the northern Siberia.