Evening star., 1952-07-04
Man Fog Phenomenon
In Arctic Being Studied
Serious Problem for Aircraft
Operators in Alosko Interior
By Thomas R. Henry
here is a "rnan fog y

There is "man fog"
A curious phenomenon Of the Arctic,
ice fog, now is being investigated by
scientists Of Stanford Research Institute
of Leland Stanford University.
During recent winters it has become a
serious problem for aircraft operations
in the interior of Alaska. Observers de-
scribe the ice fogs as being very dense
far more opaque than ordinary water
fogs-and exhibiting some rather spec
tacular optical properties. A strong beam
of light, for example, will cause the ice
crystals in the fog to scintillate. Lights
seen through the ice fog are circled by a
halo and surmounted by pillars Of light
as result of the refraction and refiec-
ton Of the light by the crystals.
Depend ON Habitation.
As result Of studies now completed it
was found that when the temperature
reached 40 F. serious ice fog would be
expected in certain areas almost half
the time. The occurrence Of serious fog
increased to almost 100 per cent during
temperature lower than So. An
important clue to the nature Of ice fog
appears to be its dependence on the pres
ence of people and their use Of fuel for
heating cooking and transportation.
The fogS are rarely reported from unin-
habited areas.
A cold chamber capable OF maintain-
ing temperature of TO now Is
being built at the institute. At the same
time ice crystals similar to those in
Alaska fogs are being manufactured in a
deep-freeze type Of cabinet. With this
apparatus the circumstances which lead
to fogs will be Investigated.
Artificial spider webs are being used to
collect the ultra minute particles with
which the atmosphere is filled.
These particles are of exceptional sig
nificance in studies of air pollution now
under way at the Stanford Research In.
stitute Of Leland Stanford University.
They also are responsible for some Of the
most important phenomena of nature.
1t is these particles which give the
sunset its brilliant hues. They contrib
ute to the blueness of the summer sky.
They themselves may be black, as in
smoke, or colorleSs as in water droplets,
but they still can produce all the colors
OF the rainbow.
They produce snogs and hazes form
ing the murky atmosphere around some
cities. They also cause disease. Men
and animals have been given protective
screens by nature against inhaling large
particles. They also are endowed with
mechanisms for expelling extremely fine
particles.
Measured In Microns.
Were 1t not for the minute particles it
, Is doubtful If rain would fall-at least
not in the way it now does.
Yet practically nothing Is known as to
which sizes are important to man, or
responsible for various phenomena.
These particles. according to the STAN
ford Research Institute report, are ex-
trenely elusive. Most Of them are SO
small that they are measured in microns.
A micron is 35,000th of an inch. An
eye that could see micron could see q
basketball on q mountaintop 100 miles
away. -.
Because Of this elusiveness the spider
web traps have been devised. They can be
mace Of pocket size. The extremely
minute fibers are electrified. The traps
are based on the physical principle that
small object is required to capture A
minute particle. BY means of the traps
representative sample of the air par
ticles from various localities is being
collected.