ATP-5-0-2-1 Staff Reference Guide Volume 1 Download
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Chapter 2 88 ATP 5-0.2-1 07 December 2020 tiltrotor aircraft in mountainous terrain. When combined with extreme temperatures, atmospheric pressure increases the amount of runway an aircraft requires for takeoff (see FM 3-04 for information on aircraft operations). Sea State 2-268. Sea state is a scale that categorizes the force of progressively higher seas by wave height (JP 4-01.6). Stated another way, sea state is the general condition of the surface on a large body of water with respect to wind waves and swell at a certain location and moment. The sea state— Is characterized by statistics, including the wave height, period, and power spectrum. Varies with time, as the wind conditions or swell conditions change. Can either be assessed by an experienced observer, like a trained mariner, or through instruments such as weather buoys, wave radar, or remote sensing satellites. See table 2-23 for sea state data. Table 2-23. Douglas sea state scale World Meteorological Organization Douglas sea scale degree Height (m) Description Douglas sea scale degree Height (m) Description 0 No wave Calm (glassy) 5 2.5–4 Rough 1 0–0.1 Calm (rippled) 6 4–6 Very Rough 2 0.5 Smooth 7 6–9 High 3 0.5–1.25 Slight 8 9–14 Very High 4 1.25–2.5 Moderate 9 14+ Phenomenal Evaluate the Effects of Weather on Military Operations 2-269. Weather and climate have direct and indirect effects on military operations. The following are examples of direct and indirect effects on military operations: Temperature inversions might cause some battle positions to be more at risk to the effects of chemical agents as a result of atmospheric ducting, a process that occurs when strong high pressure influences an area and prevents particulates from dispersing into the upper atmosphere. Local visibility restrictions, such as fog, can have an effect on observation for both friendly and threat forces. Severe restrictions to visibility often restrict aviation operations. Hot, dry weather might force friendly and threat forces to consider water sources as key terrain. Wind determines all CBRNE planning for avoiding dirty sites and establishing clean sites. Dense, humid air limits the range of loudspeaker broadcasts affecting sonic deception, surrender appeals to enemy forces, and the ability to provide instruction to friendly or neutral audiences. Sandstorms with high silica content may decrease the strength and clarity of radio and television signals. Altitude and high heat can affect the ability of military equipment to operate at maximum (or optimal) capacity. For example, in some locations during the summer months of Operation Enduring Freedom in Afghanistan, the UH-60 helicopter was unable to carry its full complement of passengers. See appendix N for more discussion on environmental considerations. 2-270. Weather effects matrices and operational impacts charts are guides for determining weather effects on personnel, weapons, and equipment needed for planning and operations (figure 2-21 is an example of a weather forecast and impacts chart).