Plentywood herald. [volume] (Plentywood, Mont.) 1908-current, 1927-10-07

Pilot balloon observations begun Aug.
/ at Havre by the weather bureau are
working out satisfactorily, according to
Frank A. Math, official in charge. This
work is being done for the first time
In Montana, and in addition to its
value to aviation will be important In
weather f0recasting, as Havre is the
outpost of storms sweeping down from
Canada.
AS the air movements In August were
light most of the time, a determination
of what the velocity is two or three miles
above the surface when the surface all
Is moving fast has not yet been reached
This study will be watched with interest
In the following statement, MIR. Math
explains the work;
fUnder direction Of Prof. c. F.. Marvin
chief of the United States weather bu-
reau, Washington, D. c., pilot balloon
observations we're started about Aug. l
at five regular weather bureau stations
one of which was at Havre.
Atmospheric Survey
pilot balloon observation are the
means of making a survey of the atmos'
phere above the earth's surface relativt
to the direction n velocity Of air
rent. as well as direction, velocity IN
height of clouds. While these surveys
are made for the benefit of aviation, they
are also useful and important to the dis
trict f~orecasters in the United States IL
making the daily surface weather fore
casts; also the collection of a number Of
years OF such data Will be an important
factor in the study and research of the
general circulation of air above the earth
THE balloons used are made OF pure
gum rubber. When inflated with hydro
gen gas the balloons are about 80 inches
In diameter. Uncolored balloons are usec
on clear rays when there is assurance OF
--L T~l~.~ A~l1~~r, ,,x,c1xt ->l
or black, are used when clouds, haze, OF
mist cause a white or grayish appearance
In the sky. The balloon used Is inflated
to nave a free lift OF 10 grams, minus
weight Of balloon, or an ascensional rate
OF 100 meters $500 feet) a minute.
Balloons Course Watched
After being released into the free air
the balloon is observed with an instru-
ment known as q t~heodolite. This instru-
ment consists of a small telescope mount
ed over a horizontal circle in such q
manner that 1T turns on a horizontal axis
through the center of the horizontal cir
Gle. The telescope is bent through al
angle Of 80 degrees. The instrument is
attached to a tripod and n appearance
resembles a surveyors transit.
1.-TWO balloon ascensions are made
daily from the roof of the weather. bu-
reau building at Havre, one at 6 a. m,
and the other at 2 p. m. Through the
eyepiece Of the telescope the skyward
curse Of the balloon is followed for 80
minutes, when that is possible. A read
ing Of the angle of elevation and All
muth are recorded from the ~theodolite
each minute.
THE distance of the balloon from the
starting point is computed from the an
giles as read and distances are plotted on
a plotting board. From those p~lottings
the resulting directions and velocities
of the upper air currents are determined.
The results for the first $50 meters, 500
meters 1,640 feet) and each 500 meters
thereafter are coded In cipher report and
t~elegraphed to the forecast districts at
Denver, Chicago. and New Orleans, all
within one hour after the balloon has
been released.
1.-THE records for the first month, Au-
gust, at Havre, have been very satisfac-
tory. although the wind movement dur
ing the month was mostly light. The
highest altitude observed In a 80 minute
period was 5,490 meters 1873 miles,
The highest velocities recorded were 43
miles IN hour at an altitude 1926 feet
above Havre on Aug. 90 and 40 miles an
hour at an altitude of $500 feet above
Havre On Aug. 81"