evaluates the data received by the radiosonde

recorder for pressure, temperature, and relative

server on Radiosonde Recorder AN/TMQ-5(*)

humidity and records the data on DA Form 4197.

Section Il. METEOROLOGICAL DATA TECHNIQUES

elevation angles from each zone. When

3-4. Use of Visual Observation Data

the pilot balloon is released from an offset

point, more than 50 meters from the ob-

be determined from surface observations of pres-

serving station, enter the data on the

sure, temperature, and wet bulb depression when

zone wind plotting board (fig. 33 ).

the station height is above sea level and the time

Enter the horizontal distance readings in

of sunrise and sunset are known.

column 4 of DA Form 4469.

(1) The surface data initially recorded on

Plotting Board ML-122 is oriented by

DA Form 4524 are used to determine

placing NORTH directly away from the

ballistic density for each line of the

plotter. Rule ML-126-A is then placed so

message.

that the edge which is in line with the

(2) The station pressure is recorded to the

pivot hole passes over the appropriate

nearest millibar.

azimuth on the plotting board (fig. 3-4)

(3) The temperatures from both the wet bulb

for the zone indicated.

and the dry bulb are measured to the

Mark the pilot balloon position on the

nearest 0.1 Celsius with Psychrometer

plotting board with a small capital *T *op-

ML-224.

posite the horizontal distance. The top of

(4) The altitude of the station is determined

the *T *is placed along the edge of the rule,

to the nearest 10 meters above sea level.

and the stem of the *T *is placed at the de-

sired horizontal distance. Each point

surface observation and entered on each line of

plotted is identified by the zone number

the message. Express this value to the nearest 0.1

at which the angular data was read. If

percent of International Civil Aviation Organiza-

the plot is made at other than the normal

tion (ICAO) standard. The temperature change

scale, the factor by which the distance is

with height will be made in accordance with the

expanded or reduced is shown after the

ICAO atmosphere lapse rate. The virtual tem-

zone number by writing a multiplication

perature is determined in percent of ICAO stan-

or division sign and the factor used.

dard and recorded on DA Form 4524 in degrees

The direction and windspeed at the sur-

Celcius.

face level is determined with the hand

c. *Ballistic density is *determined by the use of

anemometer. Convert the azimuth read-

departure tables and entries made in blocks (8),

ing of the compass reading to the nearest

(9) and (10) of DA Form 4524.

100 roils, as described in paragraph *3-3d.*

Read the windspeed directly from the

anemometer to the nearest whole knot

evaluated from artillery tables and blocks (11)

and enter this data in columns 7 and 8 of

and (12) of DA Form 4524.

DA Form 4469.

e. *Departure from mean ballistic density *is de-

termined to the nearest 0.1 percent for each line

number required and entered in block (14) of DA

and higher are read directly from the

Form 4524.

plots; use Scale ML-557/UM. A line is

drawn from the zone entered over and

beyond the next point; then, the direction

entered to the nearest 0.1 percent for each line in

is read on Scale ML-577/UM. The center

block (15) of DA Form 4524.

of the pilot balloon scale is placed over

g. *Determine the zone wind direction and speed*

the point of origin, or the plotted point

by using the information given in columns 1, 2,

where the pilot balloon entered the zone

and 3 of DA Form 4469. The zone windspeeds and

being considered.

directions are plotted as follows:

(1) Compute the horizontal distance in

meters; use the artillery tables and the

NORTH on the plotting board by align-

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