launching reel is not available, as fol-
sighting on the pilot balloon, and at the
end of the warning period (5 seconds)
(a) Observer No. 1 holds the sounding bal-
the operator will read the elevation and
loon neck. Observer No. 2 holds the
azimuth angles, as described in (4)
radiosonde set upright, by the bottom
of the case, and assumes a position the
(7) Continue the procedure given in (1)
full length of the cord, downwind from
through (6) above until the mission is
the sounding balloon.
completed, or the pilot balloon dis-
(b) Observer No. 1 releases the sounding
balloon at a given signal.
(8) Use DA Form 3675 for the transfer of
(c) As the sounding balloon ascends, ob-
ballistic data to a Ballistic MET Mes-
server No. 2 maintains a position be-
neath the drifting sounding balloon,
and holds the radiosonde set until it
f. Release of Sounding Balloons (Electronic
is lifted from the hands by the rising
Observations). Two methods are used to release
sounding balloons; mechanically with Balloon
(4) Release the spherical-type sounding bal-
Launcher ML-594/U, as described in TM 11-
loon (ML-537/UM) during high surface
6660-238-15, or manually with one or two ob-
winds, with two observers, by using a
servers. The proper procedure for release of the
running release as follows:
sounding balloon manually varies with the wind
(a) Shorten the train line by using a
conditions at the time of release. One observer
is required for release of spherical-type balloon
(ML537/UM) in calm or very light winds. The
(b) Observer No. 2 carries the radiosonde
release procedures for sounding balloons are as
set downwind until the train is taut,
while observer No. 1 carries the bal-
(1) Release the spherical-type sounding bal-
loon (ML-537/UM) in calm winds, with
(c) At a signal to release, observer No. 2
one observer, as follows:
runs with the sounding balloon until
the train line is taut, and then releases
(a) With one hand, hold the sounding bal-
the radiosonde set.
loon by the cord attached to the sound-
ing balloon neck and gradually pay
out the cord until the radiosonde set is
g. Plotting Section for Upper Air Wind Direc-
reached. With the other hand, hold the
tion and Speed Electronic Observation).
bottom of the radiosonde set case.
(1) Track and sounding balloon with the
(b) Lift the radiosonde set and allow the
rawin set as indicated in TM 116660
sounding balloon to carry it aloft.
(2) Reel, Launching ML-367/UM is used
(2) Obtain the information from the rawin
when the sounding balloon is to be re-
set control recorder printed chart (azi-
leased by one observer. Release the
muth and elevation readings) and ex-
spherical-type sounding balloon (ML-
tract the data for the required computa-
537/UM) in light winds, with one ob-
tions on the forms given below.
server, as follows:
(a) DA Form 4197 for computation of
(a) Hold the launching reel with one hand
and the radiosonde set with the other
(b) DA Form 4450 for computation of
ballistic temperatures and densities for
(b) Release the launching reel and permit
all types of meteorological messages.
the sounding balloon to rise without
(c) DA Form 4469 for computation of zone
restraint. Observer should keep di-
windspeeds and directions.
rectly beneath the balloon as it drifts
(d) DA Form 3959 for evaluation of pres-
until the sounding balloon lifts the
sure versus time.
radiosonde set from the hand.
(3) Release the spherical-type sounding bal-
(e) Chart ML-574A/UM for the determi-
loon ( ML-537/UM ) in light to moderate
nation of mean zone densities and tem-
winds, with two observers, when a
perature from radiosonde data.