The primary purpose of using NBC weapons and
smoke is to produce casualties, destroy or disable equipment,
and generally disrupt operations. NBC weapons and smoke are employed
in coordination with conventional weapons.
FM 3-3,
FM 3-4,
FM 3-5, and
FM 3-50 describe NBC defense and smoke operations. This
appendix addresses the effects of a desert environment on NBC
weapons.
WEATHER AND TERRAIN
Both desert weather and terrain affect the behavior
of NBC and smoke weapons, and to some extent influence their tactical
employment. The following paragraphs describe the effects of the
weather and the terrain on the behavior of NBC weapons.
Weather
The effectiveness of NBC and smoke weapons is
directly proportional to air stability. Air stability is a result
of temperature variations at different levels of the air. The
span of desert day and night temperatures causes extremes of air
stability. At night and early morning the desert air is very stable.
This may be the best time for NBC and smoke employment because
of extensive downwind drift and area coverage. Desert air is very
unstable during the late morning through afternoon. This may be
the worst time for NBC and smoke employment because of quick and
irregular dissipation. This may lead to ineffective target area
coverage and possible danger to friendly troops. Temperature differences
are determined by comparing the air temperature differences every
3.5 meters above the ground. Three types of temperature differences
influence NBC and smoke operations:
- Unstable (lapse). Unstable conditions exist
when air temperature decreases with altitude. In the desert, this
mostly occurs between late morning and early evening.
- Neutral. Neutral conditions exist when air
temperature does not change with altitude, In the desert, this
mostly occurs during early morning and early evening.
- Stable (inversion). Stable (inversion) weather
conditions exist when the air temperature increases with altitude.
In the desert, this mostly occurs between late evening and early
morning.
High desert temperatures in the middle of the
day result in a decrease in air density, so nuclear blast waves
move faster. Some chemical agents that come in contact with the
skin are more effective during high temperatures due to perspiration.
Desert sunlight is lethal to the effectiveness of most biological
agents, but most are unaffected at night.
High winds are common in certain desert seasons
and affect the dissemination of biological, chemical, smoke, and
radioactive clouds. High winds may break up clouds in an odd fashion
and force them in the wrong direction and possibly endanger friend]
y troops.
Terrain
Flat desert terrain lacking vegetation and under
stable air conditions moves NBC and smoke effects evenly and steadily
in all directions. Nuclear induced radiation is greater in sandy
soil due to the high silica content. Desert soil below the surface
crust is a fine powder, so the blast and suction effects of a
nuclear burst will cause considerable dust clouds.
NUCLEAR WEAPONS IN THE
DESERT
Many potential threat nations maintain nuclear
weapons and additional nations continue to obtain nuclear capability.
Nuclear weapons can be delivered by missiles or bombs and can
be exploded in the air, on the ground, or below the ground. Depending
upon the radiation dosage received, lethal effects could be felt
immediately or delayed for days. Detonated nuclear weapons release
energy that affects military troops and equipment in three forms:
blast, nuclear radiation, and thermal radiation (heat and light).
These effects are discussed in the following paragraphs.
Blast
Nuclear blasts, even from an air burst, raise
considerable amounts of desert sand and dirt, which inhibits observation
and maneuver for a long time. Lighter desert air density causes
a drop in static overpressure, but a more rapidly expanding blast
(shock) front. This increases the danger to aircraft and helicopters
flying in the area. The radius of damage is normally smaller in
desert climates so dug-in personnel and equipment are safer. Desert
trafficability is degraded in the immediate area of the strike,
especially for wheeled vehicles, due to the destruction of the
sand crust.
Nuclear Radiation
Immediate nuclear radiation is a function of
weapon yield and changes little with desert temperature. Residual
radiation is high in the case of low air burst or ground burst
weapons. Residual radiation in the desert is affected by the time
of day and the wind. At night, with no wind, residual radiation
may be evenly distributed around the point of burst. At night,
with a steady wind, residual radiation may drift downwind for
many miles. In the late afternoon, residual radiation may drift
in a totally irregular pattern and direction due to desert air
instability. Induced radiation is prevalent in desert sand due
to the amount of silica in the soil. Constant radiation monitoring
and reconnaissance are vital to protect troops, especially from
contaminated water sources.
Thermal Radiation
The effective range of thermal radiation (heat
and light) increases in the desert where there is little terrain
masking. This increases the danger of troops receiving severe
burns. Blinding light (dazzle), out to 50 kilometers, must be
considered in the desert when determining the radius of warning
for friendly troops.
BIOLOGICAL WEAPONS IN THE
DESERT
The United States has renounced the use of biological agents, but many potential threat nations maintain biological weapons. Biological agents are living microorganisms that multiply inside the human body and cause disease. Biological agents may be disseminated as a liquid or vapor using rockets, bombs, or aerosol generators.
Depending upon the agent, they can produce lethal
effects in 1-24 days from the time of exposure. High desert temperatures
(120 degrees Fahrenheit and higher) and sunlight may destroy most
biological agents. Cooler nighttime temperatures and the lack
of sunlight provide biological agents a chance to enter the body.
High desert winds will disperse biological agents more rapidly
than low winds. Normally, the most effective wind speeds for
effective target coverage are from 8-18 knots (14-32 kmph). Stable
desert air conditions (night or early morning) provide the greatest
agent concentration and area coverage. Unstable desert air conditions
(late morning and afternoon) promote atmospheric mixing and lower
agent concentration, reducing effective target coverage.
Biological weapons are best suited for strategic
rather than tactical use in the desert. Test water and food sources
frequently to ensure they are not contaminated. Sanitation, personal
hygiene, and immunizations must be instituted to ensure individual
protection.
The United States also renounces the use of toxins
but some potential threat countries continue to develop toxins
for possible military use. Toxins are extracted from natural biological
sources and are not chemicalIy produced. They can be disseminated
as a liquid, vapor, or powder, and delivered by aerosol generators,
artillery, rockets, or bombs. Depending upon the toxin, they can
produce lethal effects in one minute to 12 hours from the time
of exposure. In the desert, toxins can effectively be used as
strategic or tactical weapons.
CHEMICAL WEAPONS IN THE
DESERT
The United States has reserved the right to retaliate
in kind with chemical agents against enemies who use them frost.
There are six major types of chemical agents: nerve, blood, blister,
choking, incapacitating, and tear. They are classified as persistent
and nonpersistent. Chemical agents may be delivered by mines,
rockets, artillery, or bombs. Depending upon the agent type, lethalities
can occur between minutes to an hour from the time of attack.
High daytime temperatures of the desert increase
incapacitating effects of liquid agents, which rely on skin penetration.
Desert air instability (late morning and early afternoon) will
usually cause quick, vertical and irregular dissipation of chemical
agents. This reduces the lethal concentration and target area
coverage. Desert air stability (early morning and evening) will
most likely cause adequate agent dissipation and target area coverage.
High desert temperatures also cause liquid agents to evaporate
more quickly and decrease the time of hazard. If a liquid chemical
agent soaks into the desert sand, it will increase the time of
hazard. Figures D-1 and
D-2 show the evaporation times of chemical
agents (HD, GA, GF, VX) on sand at 104 and 68 degrees Fahrenheit
for negligible risk levels. Negligible risk levels cause mild
incapacitation among no more than 5 percent of unprotected soldiers/marines
crossing a contaminated area.
Strong desert winds also increase the evaporation
rate of liquid agents. They cause chemical clouds to drift downwind
in an irregular direction and concentration. This tends to disperse
target area coverage and lethal concentrations, and may endanger
friendly troops.
SMOKE SYSTEMS IN THE DESERT
The lack of cover and concealment in flat desert
terrain with little vegetation makes the use of smoke more vital
to survival.
Desert winds, temperature, humidity, and terrain
all affect smoke cloud behavior. The weather condition with the
greatest impact on smoke operations is wind. Low desert winds
al1ow smoke to remain on target areas for a longer period of time
than high winds, In general, if the wind speed is less than 5
knots (9 kmph) or greater than 10 knots (18 kmph), smoke may not
provide good target area coverage.
Temperature
Desert temperature differences have a direct
relationship with making effective smoke. Three types of temperature
differences influence smoke:
- Unstable (lapse). Lapse desert temperatures
tend to break up and dissipate smoke, but are best for producing
smoke curtains.
- Neutral. Neutral desert temperatures have limited
vertical air currents and are good, but not the best, for producing
smoke hazes and blankets.
- Stable. Stable (inversion) desert temperatures
have no vertical air currents, and are the best for producing
smoke hazes and blankets.
Humidity
Practically all smoke particles absorb moisture
from the air. The lack of moisture in the desert air decreases
the particle size and density of smoke making it less effective.
Desert smoke streamers are shorter and less dense than smoke streamers
in humid weather conditions. This increases the time and distance
required to build adequate target area coverage.
TACTICS
The effects of NBC weapons and smoke on tactics
in desert operations are discussed in the following paragraphs.
Nuclear
Nuclear weapons have a major bearing on tactics
because of their ability to contaminate and shape desert terrain
by making it impassable. Nuclear weapons can destroy troop and
equipment concentrations and command and control centers and are
usually considered weapons of mass destruction and combat multipliers;
therefore, a smaller force with nuclear weapons may well defeat
a much larger force without nuclear weapons.
The high maneuverability of tracked vehicles
in the desert produces an endless number of avenues of approach.
This creates difficulties for defense operations in the desert.
Nuclear explosions could be used to shape desert terrain and canalize
an enemy. This would provide profitable targets for other weapon
systems. Equally, an attacking force could employ nuclear weapons
in the desert to cut off enemy reinforcements, isolating them
and making them vulnerable.
Biological Agents/Toxins
High desert temperatures and sunlight prevent
the effective use of most biological agents during the daytime.
An exception is spore-forming (anthrax) biological agents. During
the day, troops crossing or occupying desert terrain face little
danger from long-term biological contamination (except from spore-forming
agents). But, because of favorable night desert conditions, an
aerosol-delivered attack or a liquid biological attack would be
effective. During night desert conditions, biological agents could
effectively cover hundreds of square kilometers with a small amount
of agent. This type of attack could be conducted covertly. These
agents could contaminate vast areas of terrain and create mass
casualties.
Toxins in the desert have nearly the same military
use as chemical agents and are employed in the same manner. However,
toxins are more deadly and require lower concentrations for lethalities.
Toxins are difficult to detect with today's standard detection
equipment.
Chemical Agents
The versatility of chemical agents gives commanders
flexibility in desert operations. Commanders must consider how
the employment of chemical agents affect offensive and defensive
desert operations. Chemical agents can be used to create casualties,
degrade performance, slow maneuver, restrict terrain, and disrupt
logistical support. An assaulting force could use chemical agents
to breach a defense or widen a gap. The best agent to use in this
case would be a nonpersistent agent (one that is fast acting and
leaves the target area quickly). High explosives could be mixed
with the chemical attack to conceal the use of chemicals and complement
their effects.
The threat of a chemical attack forces the use
of protective masks and clothing. Heat, fatigue, and stress seriously
affect the performance of troops. This is especially true with
high desert temperatures. Well-trained soldiers/marines tolerate
wearing protective gear better than those who are not as well
trained. Troops in protective gear fire weapons less accurately,
move more slowly, and must rest more often.
The actual or anticipated use of chemical weapons
slows down a force and forces troops to take precautions. Desert
heat, fatigue, and stress caused by wearing protective equipment
slows down unit movement. Chemical agents can be used to create
contaminated obstacles to desert maneuver. The best agent to use
in this case would be a persistent chemical agent (one that remains
on the target area for a time).
Chemical agents could be used to support offensive
desert operations. Chemical agents could be used to protect flanks
along an axis of advance to slow enemy counterattacks and to slow
enemy fire and movement. In defensive desert operations, chemical
agents could be used against second echelon forces to separate,
slow down, and isolate them.
Chemical agents could be used to supplement conventional
obstacles, or they could be used alone to restrict desert terrain.
They may slow maneuver and channel attackers into engagement areas.
A commander could contaminate a narrow desert mountain pass or
bridge with a chemical agent and force the enemy to use an alternate
route.
Logistical centers are lucrative targets for
desert chemical attacks. Contaminating logistical supplies and
equipment reduces the mobility of reinforcements and slows the
delivery of supplies and equipment.
Smoke
Smoke is a combat multiplier that enhances the
commander's ability to concentrate combat power at the critical
time and place. Smoke is a far more significant battlefield factor
than ever on flat desert terrain with little cover and concealment.
Smoke can defeat enemy binoculars, weapon sites, and laser range
finders in the desert. Smoke placed on the enemy at night interferes
with enemy operations and observation by defeating enemy night
sights and infrared sights.
In the desert offense, smoke can be used to deny
the enemy information about the size, composition, and location
of friendly maneuver forces. A smoke screen can be placed either
to the front or to the flank. When the enemy cannot be screened
effectively, obscuring smoke may be required. We must keep the
enemy in doubt about the attacking unit's strength, position,
activities, and movement. The longer the enemy is in doubt during
an operation, the greater the chances are for mission success.
Also, smoke can conceal desert breaching operations and river
or gap crossings. It can also be used in deception operations.
In the desert defense, smoke is used to deny
the enemy information about the size, location, and composition
of friendly defensive positions. We must deny the enemy information
by concealing the preparation and location of battle positions,
artillery units, and reserves. Smoke can be used to support desert
defensive positions by slowing enemy maneuver, disrupting command
and control, isolating attacking echelons, silhouetting targets,
and concealing obstacles.
PROTECTION
The commander of troops in desert operations
must choose between the two following options when there is the
threat of NBC warfare:
- Troops remain unprotected, with a high-chemical
casualty risk, but a lower chance of heat fatigue.
- Troops are fully or partially protected, with
a low-chemical casualty risk, but a higher chance of heat fatigue.
A decision on the level of protection is made
according to the circumstances. If partial protection is ordered,
the pace of physical work will be slower and proficiency reduced.
The bulk of strenuous physical activity must be done at night
or during the coolest part of the desert day.
In the desert, heat casualties (5 percent minimal)
can be expected to occur in 30 minutes while performing heavy
work in 90-degree-Fahrenheit temperatures when dressed in MOPP
4. Work/rest periods must be utilized to reduce the chances of
heat fatigue. When protective clothing is worn, at least 10 degrees
should be added to the WBGT index. Because of higher body temperatures,
soldiers/marines in MOPP equipment perspire more than usual. Water
must be consumed (2 quarts per hour) during continuous moderate
work periods (and in MOPP equipment) when temperatures reach 80
degrees Fahrenheit and above to replace lost fluids or dehydration
will follow.
DECONTAMINATION
The main problem of decontamination in the desert
is lack of water, Although decontamination takes place as far
forward as possible, the lack of water may burden the logistical
system. Weathering may be a viable option for chemical contamination.
The persistency of nerve agents (GA, GF, VX, GD) and mustard (HD)
on chemical agent resistant coating (CARC) painted vehicles is
between 4-24 hours at 104 degrees Fahrenheit. Sea water may be
used as a substitute for fresh water during normal decontamination
operations, but all equipment must eventually be flushed with
fresh water to prevent corrosion.
Desert sand can be used for chemical decontamination, but it increases soldier/marine fatigue during its application. Sand removes most, but not all, liquid contamination, and saves valuable water supplies; however, the absorption capacity of desert sand is exhausted in 30-60 seconds after application. Remove the sand by sweeping or brushing the contaminated surface. Chemical agent detection should be conducted to ensure the agent is adequately removed.
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