FM 6-16
10 MAY 1979
By Order of the Secretary of the Army:
BERNARD W. ROGERS
General, United States Army
Chief of Staff
Official:
J. C. PENNINGTON
Major General, United States Army
The Adjutant General
DISTRIBUTION:
Active Army, USAR and ARNG: To be distributed in accordance with DA Form 12-11A,
Requirements for Tables for Artillery Meteorology (Qty rqr block no. 38).
Additional copies can be requisitioned from the US Army Adjutant General Publications Center,
2800 Eastern Boulevard, Baltimore, MD, 21220.
✰ U.S. GOVERNMENT PRINTING OFFICE: 1994 - 342-421/81400
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HEADQUARTERS
DEPARTMENT OF THE ARMY
Washington, DC, 1 March 1982
CHANGE
NO 1
TABLES FOR ARTILLERY METEOROLOGY
(ELECTRONIC) BALLISTIC TYPE 3
AND COMPUTER MESSAGES
FM 6-16, 10 May 1979, is changed as follows:
1. New or changed material is indicated by a star(*).
2. Remove old pages and insert new pages as indicated below:
REMOVE
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INSERT
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3. File this change in the front of the publication for reference.
By Order of the Secretary of the Army:
E. C. MEYER
General, United States Army
Chief of Staff
Official:
ROBERT M. JOYCE
Brigadier General, United States Army
The Adjutant General
DISTRIBUTION:
Active Army, ARNG, and USAR: To be distributed in accordance with DA Form 12-11 A, Requirements for Tables for Artillery Meteorology (Qty rqr block no. 38).
Additional copies may be requisitioned from the US Army Adjutant General Publications Center,
2800 Eastern Boulevard, Baltimore, MD 21220.
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CHAPTER 1
INTRODUCTION
1-1. PURPOSE AND SCOPE
a. This manual is a compilation of tables
and charts designed for use in computing
meteorological messages for the artillery,
including ballistic and computer messages,
radiological fallout prediction, and messages
for transmitting data to Air Weather Service
units. These tables and charts apply to all
types of ballistic meteorological observations
by electronic met sections using radiosondes.
Use of this manual in the computation of
messages is described in FM 6-15, Artillery
Meteorology.
b. Users of this manual are encouraged to
submit recommended changes or comments
to improve the manual. Comments should be
keyed to the specific page, paragraph, and
line of the text in which the change is
recommended. Reasons should be provided
for each comment to insure understanding
and complete evaluation. Comments should
be prepared using DA Form 2028
(Recommended Changes to Publications)
and forwarded direct to Commandant,
United States Army Field Artillery
School, ATTN: ATSF-CF-R, Fort Sill,
Oklahoma 73503.
★ c. FM 6-16, Tables for Artillery
Meteorology, has been revised into a set of
four field manuals. The set includes:
❑ FM 6-16
Tables for Artillery Meteorology (Electronic) Ballistic
Type 3 and Computer
Messages.
❑ FM 6-16-1
Tables for Artillery Meteorology (Sound Ranging)
Messages.
❑ FM 6-16-2
Tables for Artillery Meteorology (Visual) Ballistic
Type 3 and Computer
Messages and Limited
Surface Observations.
❑ FM 6-16-3
Tables for Artillery Meteorology (Electronic and
Visual) Type 2 Messages.
1-2. DESCRIPTION OF TABLES
AND CHARTS
The tables and charts contained in this
chapter are presented in sections I and II as
follows:
a. Section I, General Tables and Charts for
Meteorological Messages. These tables and
charts are used in computing data for both
electronic ballistic and computer
meteorological messages.
b. Section II, Tables for Type 3 Messages,
Ballistic Messages for Surface-to-Surface
Trajectories. These tables include the
weighting factors and the weighted
quantities for density, winds, and
temperatures pertaining to all artillery
weapons firing at terrestrial targets and
tables for standard conditions at ballistic and
computer zone midpoints.
1-3. TIME ZONES, GLOBAL
OCTANTS, AND CLIMATIC
REGIONS
Figure 1-1 divides the world into time zones,
global octants, and climatic regions, used in
the heading of meteorological messages.
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CHAPTER 2
METEOROLOGICAL TABLES AND CHARTS
SECTION I.
GENERAL TABLES AND CHARTS
FOR METEOROLOGICAL MESSAGES
2-1. GENERAL
The tables and charts included in this
chapter are used for computing general
meteorological data for all types of
meteorological messages.
2-2. ZONE STRUCTURE OF
ATMOSPHERE
For convenience in computing, reporting,
and applying corrections, the standard
atmosphere is further identified by dividing
it into zones for standard heights. The
zones for the various meteorological
messages are illustrated in figure 2-1.
2-3. HORIZONTAL DISTANCE
TABLES
a. Horizontal distance tables are
computed for the standard heights of the
zone structure as shown in figure 2-1 and for
a curved Earth surface according to the
following formula:
b. In this formula, D is the arc distance
of the Earth’s surface in meters and is the
elevation angle to a balloon at standard
height H. R is the average radius of the
Earth, 6,367,650 meters.
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2-4. CONVERSION OF WIND SPEED
Figure 2-2 is used to convert wind speed in knots and miles per hour.
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2-5. PRESSURE CONVERSION
The millibars of pressure for a certain number of inches of mercury maybe determined
from figure 2-3.
Formula: 1,000 Millibars = 29.53 inches of Mercury.
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2-6. CONVERSION OF PRESSURE TO PERCENT OF STANDARD
The conversionof surface pressure in millibars to percent of the standard mean sea level
(MSL) pressure is accomplished by use of the chart in figure 2-4.
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2-7. PRESSURE TO CONTACT CONVERSION
The conversion of pressure in millibars to contact value in tenths, or vice versa, is
accomplished by use of the chart in figure 2-5.
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2-8. RELATIVE HUMIDITY
Relative humidity may be determined by use of a psychrometer and psychrometer
tables or by use of the chart in figure 2-6.
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2-9. TABLE OF CORRECTIONS USED TO DETERMINE VIRTUAL
TEMPERATURE FOR PLOTTING CHART ML-574( )
a. Table 2-4 provides temperature multipliers which, when multiplied by relative
humidity values (i.e., 45% = 0.45, etc.) and added to the observed temperature values,
yield virtual temperatures.
b. Enter the table with the observed air temperature rounded off to the nearest
whole degree Celsius and the observed pressure rounded off to the nearest 50 millibars.
If the observed pressure value ends with 25 of 75 (e.g., 925 or 775), round off to the lower
50-millibar value. Do not interpolate.
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SECTION II.
TABLES FOR TYPE 3 MESSAGE, BALLISTIC MESSAGE
FOR SURFACE-TO-SURFACE TRAJECTORIES
grams per cubic meter to zone densities in
2-10. GENERAL
percent of standard for that zone and to
Tables 2-5 through 2-10 contain the
weighting factors used in obtaining a
type 3 meteorological message. Some of
the tables present the weighting factors
directly; in others, the weighting factors
are used to determine the effect of the
various zone values on the line values of
the meteorological message. The
weighting factors used are those
approved, on an interim basis, by the
fifth meeting of the NATO Group on
External Ballistics, November 1960.
2-11. WEIGHTED DENSITY
TABLES (TYPE 3 MESSAGE)
a. The weighted density tables give
the weighted densities for the type 3
message (surface-to-surface firing). They
may be used to convert zone densities in
convert zone densities to the weighted
effect of these zone densities on the
various line values of the meteorological
message.
b. The values in the Density %
column were
computed by dividing the
3
GM/M value by the zone midpoint
standard density.
c. The Line-zone No. values were
computed by multiplying the Density %
values by the weighting factors shown in
table 2-5. Line-zone No. 21 is the product
of the weighting factor (.43), line 2 of zone
number 1, table 2-5, and the Density %
value. Line-zone No. 32 is the product of
the weighting factor (.31), line 3 of zone
number 2, table 2-5, and the Density %
value.
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2-12. SURFACE DENSITY, PERCENT OF STANDARD
The surface density, in grams per cubic meter and expressed as a standard surface
density, may be determined from the chart in figure 2-7.
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2-13. SURFACE TEMPERATURE, PERCENT OF STANDARD
The conversion of surface temperature to percent of standard surface temperature is
accomplished by use of the chart in figure 2-8.
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2-14. WEIGHTED TEMPERATURE TABLES (TYPE 3 MESSAGE)
a. The weighted temperature tables (table 2-8) may be used to convert zone
temperatures in degrees Celsius to zone temperatures in percent of standard for each
zone. They may also be used to convert zone temperatures to the weighted effect of
temperature on the various line values of the meteorological message.
b. The Zone temperature % column is the quotient of the zone temperature divided
by the standard zone temperature.
c. The Line-zone No. values are the product of the weighting factors in table 2-7 and
the Zone temperature % values. The Line-zone No. values of column 21 are the product of
the weighting factor (.27), line 2 of zone number 1, table 2-7, and the Zone temperature %
values.
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2-15. Weighted Wind Speed Tables (Type 3 Message)
a. The weighted wind speed tables (table 2-10) may be used to convert zone winds to
the weighted effect of these winds on the various line values of the meteorological
message.
b. The Line-zone No. values are the product of zone wind values and the weighting
factor values shown in table 2-9. The values of Line-zone No. 21 are the product of zone
wind speeds and the weighting factor (.20), line 2 of Zone No. 1, table 2-9.
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