ATP-5-0-2-1 Staff Reference Guide Volume 1 Download
Page 103 of 440
Planning 07 December 2020 ATP 5-0.2-1 87 Wind 2-260. Wind of sufficient speed from any direction can reduce the combat effectiveness of a force as a result of blowing dust, smoke, sand, or precipitation. Wind direction is the direction from which the wind is blowing. For example, a southerly wind blows from south to north. Strong winds and wind turbulence limit airborne, air assault, and aviation operations. High winds near the ground can lower visibility due to blowing dust; they also can affect movement or stability of some vehicles. Blowing sand, dust, rain, or snow reduces the effectiveness and stability of radars, antennas, communications, and other electronic devices. High winds can also affect persistent friendly and threat detection systems like an aerostat or unmanned aircraft systems (UASs). Evaluation of weather to support operations requires information on the wind at the surface as well as at varying altitudes and elevations. Winds also affects the use of smoke for obscuration and chemical, biological, radiological, and nuclear effects (CBRN). Precipitation 2-261. Precipitation is any moisture falling from a cloud in frozen or liquid form. Rain, snow, hail, drizzle, sleet, and freezing rain are common types. Precipitation affects soil trafficability, visibility, and the functioning of many electro-optical systems needed for IC. Heavy precipitation can have an effect on all types of military operations. Cloud Cover and Ceiling 2-262. Cloud cover and ceiling affects ground operations by limiting illumination and can affect the thermal signature of targets. Heavy cloud cover and ceiling can degrade many intelligence sensors, target acquisition systems, and general aviation operations. Conversely, low cloud cover and ceiling may increase the available level of light where ground-based light exists, such as urban areas. Excessive low cloud cover and ceiling may restrict visibility and limit safe aviation operations. 2-263. Cloud cover and ceiling means the height above the Earth's surface of the lowest layer of clouds or obscuring phenomena that is reported as broken, overcast, or obscured and not classified as thin or partial. A ceiling listed as "unlimited" means that the sky is clear or is free of any substantial cloud cover. Temperature 2-264. Temperature extremes can reduce the effectiveness of troops and equipment capabilities and affect the timing of combat operations and major operations. Extremely high temperatures in a desert environment may require dismounted troops to operate at night. High temperatures can affect the lift capability of medium-rotary-lift assets in high altitudes and elevations. High temperatures can increase fuel consumption in vehicles, cause overheating, and affect the muzzle velocity of both direct and indirect fire weapons (155 millimeter howitzers, sniper rifles, and tanks). 2-265. Thermal crossover is the natural phenomenon that normally occurs twice daily when temperature conditions are such that there is a loss of contrast between two adjacent objects on infrared imagery (JP 3-09.3). Stated another way, thermal crossover is the condition in which the temperature of a ground- based vehicle is close to, if not the same as, the surrounding land. As a result of this condition, thermal optics are unable to detect enemy vehicles until a temperature disparity exists between the land and the vehicles. Using target acquisition weather software, meteorological and oceanographic personnel can forecast for thermal crossover and determine specific times that the phenomenon will occur. Humidity 2-266. Humidity is the water vapor content of the atmosphere, usually expressed as either relative humidity or absolute humidity. High humidity affects the human body's ability to cool off. Troops in tropical areas may become less effective due to higher humidity levels. Atmospheric Pressure (as Required) 2-267. Atmospheric pressure significantly impacts aviation operations. Based on the elevation of the operational area, atmospheric pressure affects the lift capacity of aircraft, especially rotary-wing and