air defense visual and radar target acquisition and tracking systems, and the
accuracy of air defense weapons to varying degrees.
Heavy, moist air during rainstorms will affect airborne operations, causing
parachutists and air-dropped equipment to remain airborne longer and to descend
slower. While heavy air drops can result in fewer personnel injuries and less
equipment damage, personnel are exposed to enemy fire for much longer periods.
Cloud cover and ceiling impose severe restrictions on aircraft operations. The
existing cloud cover limits or enhances aerial visibility, and concealment
restricts CAS and airborne or air resupply operations and establishes the maximum
altitude of air avenues of approach for non-all-weather capable aircraft. Aviators
avoid thunderstorms and snow clouds because of their potential to generate winds
and turbulence beyond aircraft stress limits, hail, and icing conditions. Certain
types of cloud cover are associated with violent updrafts and downdrafts which
radically affect aircraft altitude and air defense weapon accuracy. Clouds trap
heat from the earth and sun raising temperatures near the ground, causing a
reduction in aircraft lift rates and rotary-wing hover capabilities.
Heavy cloud cover often canalizes aircraft within air avenues of approach and
during the final approach to the target, and may decrease the effectiveness of
aircraft camouflage. Knowledge of such canalization will assist the analyst in
determining where friendly and enemy air defense weapons and radars should be
emplaced. Certain types of clouds, especially clouds associated with
thunderstorms, will reduce the effectiveness of air defense radars. Power surges
associated with thunderstorms can damage unprotected air defense and aircraft
electrical and communications systems. Figure 1-10 shows an example of the effects
of cloud cover on air avenues of approach.