Manual of Aerography for the United States Navy, 1918U.S. Government Printing Office, 1918 - 165 pages |
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Aerography aeroplane altitude anemoscope anticyclone atmosphere average aviator balloons barograph barometer calories cent centimeter Chapter cirrus clouds coast column cubic Cumulo-nimbus cumulus cumulus clouds currents cyclonic danger decrease density depression direction drum earth east easterly electricity Equator fall flow flying force Forecasting gale gases gradient grams halo heat height horizon humidity hyperbar inches increase instrument isobars kilobars Kilograms Kilome kilometers latitude layer light line squall maximum McAdie mean Meteorological meters per second miles per hour Monthly Weather Review motion movement moving Naval Aerographic Stations nimbus northeast Northern Hemisphere northwest observations occur parallel pilot Principles of Aerography radiation rain record sheet region rise Royal Meteorological Society saturation solar southeast southwest square storm summer surface TABLE temperature thermometer thunderstorm unit upper velocity vertical warm water vapor wet bulb wind winter
Popular passages
Page 46 - Isolated hills, especially short or conical ones, should be avoided during warm still days, for on such occasions their sides are certain to be warmer than the adjacent atmosphere at the same level, and hence to act like so many chimneys in producing updrafts. Rising air columns occur less frequently and are less vigorous over water, and over level green vegetation, than elsewhere. They are also less frequent during the early forenoon than in the hotter portion of the day, and practically absent...
Page 90 - CUMULO-NIMBUS (Cu. N.). Thunder cloud ; shower cloud. Heavy masses of clouds, rising like mountains, towers, or anvils, generally surrounded at the top by a veil or screen of fibrous texture (" false cirrus ") and below by nimbus-like masses of cloud.
Page 45 - On grazing the column, with one wing of the machine in the rising and the other in the stationary air; a condition that interferes with lateral stability and produces a sudden shock both on entering the column and on leaving it. 2. On plunging squarely into the column; thus suddenly increasing the angle of attack, the pressure on the wings, and the angle of ascent. 3. On abruptly emerging from the column; thereby causing a sudden decrease in the angle of attack and also abruptly losing the supporting...
Page 90 - ... of the sailors. 8. Cumulus (Cu.). — Wool pack clouds. Thick clouds whose summits are domes with protuberances but whose bases are flat. These • clouds appear to form in a diurnal ascensional movement, which is almost always apparent. When the cloud is opposite the sun the surfaces which are usually seen by the observer are more brilliant than the edges of the protuberances. When the illumination x-omes from the side this cloud shows a strong actual shadow; on the sunny side of the sky, however,...
Page 101 - ... again in longer periods, and ranging over irregular fluctuations of from 2 to 10 per cent of the total. It has also been shown by Abbot, Fowle, Kimball, and others that great volcanic eruptions materially decrease the apparent solar radiation, or rather that atmospheric transmissibility undergoes marked changes with consequent diminution of temperature. Marked changes occurred in 1884-1886 (probably connected with Krakatau) and again in 1903-4.
Page 49 - It is also well to avoid making great changes in altitude, since wind sheets, of whatever intensity, remain roughly parallel to the surface of the earth, and the greater the change in altitude the greater the risk of running into a treacherous "hole." Also, lest there might be a wind sheet near the surface, and for other good reasons, landings should be made, if possible, squarely in the face of the surface wind. WIND BILLOWS. It was stated above that when one layer of air runs over another of different...
Page 47 - Ordinarily, it does not come very near the ground, where indeed there frequently is a countercurrent, but remains at a considerable elevation. Other things being equal. it is always most pronounced when the wind is at right angles to the direction of the ridge and when the mountain is rather high and steep. The swift downward sweep of the air when the wind is strong may carry...
Page 90 - Alto-stratus (AS). Thick veil of a gray or bluish color, exhibiting in the vicinity of the sun and moon a brighter portion, which, without causing halos, may produce coronas.
Page 45 - ... smoke occasionally seen to rise from chimneys. The -velocity of ascent of such fountains of air is, at times, surprisingly great. Measurements on pilot balloons, and measurements taken in manned balloons, have shown vertical velocities, both up and down, of as much as 10 feet per second. The soaring of large birds is a further proof of an upward velocity of the same order of magnitude, while the fact that in cumulus clouds water drops and hailstones often are not only temporarily supported, but...
Page 50 - There may be some danger also at the forward side of the eddy where the downward motion is greatest. When the wind is blowing strongly landings should not be made, if at all avoidable, on the lee sides of, and close to, steep mountains, hills, bluffs, or even large buildings; for these are the favorite haunts, as just explained, of treacherous vortices.