White Bluffs spokesman. [volume] (White Bluffs, Wash.) 1907-1938, 1925-04-10
HEATING and COOLING
OF The ATMOSPHERE

A crowd of between IS and 20
growers were out at the high school
auditorium Tuesday evening to listen
to a very interesting discussion on
orchard thermometers, orchard heat
ing and heaters, atmospheric and
climatic conditions conductive to
frost damage and kindred subjects
relating to orchard heating, by AL
bert w. Cook, assistant observer,
U. S. Weather Bureau, located at
Kennewick. Mr.. Cook spoke for
about two hours and the close at
tention and frequent questions of
his hearers indicated the interest
with which his talk was being re-
ceived. Percy Combelic, a grower
at Kennewick also spoke briefly on
some of his experiences in orchard
heating.
The following article on the heat
ing and cooling of the atmosphere
prepared by DR.. Cook was handed
by him to the Spokesman for pub
LEGATION this week.
All frost protection methods, from
the simplest to the most complicated,
can be carried on more successfully
if the processes by which the earth
surface cools at night and the fac
tors which influence the rate Of
cooling are well understood.
There are three processes of heat
transfer, namely, convection, con-
duction and radiation. In the study
of the cooling of the atmosphere at
night and the resulting low teinpera-
lures which cause frost only the last
two processes will be considered.
However, convection is the chief
factor in the heating of the air by
day.
1t is matter of everyday ex-
perience that if one end of a bar
of metal is placed in fire the other
end becomes hot. This interchange
of heat from one portion of body
to another, or between two separate
bodies in actual contact is called
conduction. The rapidity with which
the heat is transferred from one part
of the substance to the other in
dicates whether the substance is
good or poor conductor. Iron is an
excellent conductor while wood is
very poor conductor of heat. The
earth and the atmosphere surround
ing it are very poor conductors of
heat.
Radiant energy is minute wave
disturbance. The sun is constantly
radiating energy about one two-b.l-
lionth of which is received by the
earth. The radiant energy striking
the earth makes itself manifest in
one of four different ways. It may
heat the object upon which it strikes.
If the waves enter the eye they
will produce vision. 1t is only the
waves of intermediate wave length
that causes vision, however. 1t may
produce chemical change. An ex-
ample is the exposure Of a photo
graphic film. Only very small part
is used up in the causing of chemi-
cal changes. The fourth effect is the
changing of state. A large amount of
the radiant energy which falls upon
bodies OF water is expended in evap-
Grating part of the water and 'caus-
ing 1t to pass into the atmosphere
as vapor. We are concerned only
with the first process here.
The energy radiated from the sun
passes to the earth thru the oO0CO.-
600 miles OF intervening space at the
enormous rate Of 186,330 miles per
second. Because of the dust particles,
water vapor. etc. in the air CON
siderable resistance is offered to the
passage Of the radiant energy thru
it with a resulting heating of the
air in immediate contact with the
Garth. All substances radate energy
at all times. II the outgoing radia
ton exceeds the incoming the SUBJ
stance cools. The converse is also
true. The earth is constantly radiat-
ing heat to the upper limits of the
atmosphere, region Of intense cold.
During the day the heat received
from the sun is far in excess of the
amount given off by the earth and
the temperature of the earth rises.
After the sun sets there is no heat
received to counterbalance that given
of and the Garth cooIs.
During clear, calm days the tenn
perature of the earth is raised by
the radiant energy received from the
sun and the air in immediate contact
is warmed by conduction. Since the
air is poor conductor only the air
IN immediate contact with the Garth
is warmed at first. But as the air
becomes lighter and the cold air
around and above it forces 1t to rise
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