part of has quality has member composed primarily of object aggregate water droplet water ice crystal altostratus cloud Altostratus-Wolke A cloud which 1) occurs in the form of a striated, fibrous, or uniform sheet or layer, 2) is composed of water droplets and ice crystals, 3) is located in the middle level of the atmosphere (middle étage). Add more PATO qualities once they have been added to PATO. As Mittelhohe Schichtwolke envoAtmo Striation occurs in the form of grooves or channels in cloud formations, arranged parallel to the flow of the air. When well-illuminated by sunlight (excluding during sunrise and sunset) altostratus clouds appear greyish or bluish. Altostratus clouds do not show halo phenomena when scattering visible range stellar radiation. Altostratus clouds have parts thin enough to reveal the local star at least vaguely, as through ground glass or frosted glass. Altostratus may produce rain, snow or ice pellets. Altostratus is usually found in the middle level, but it often extends higher. Altostratus is generally a layer of great horizontal extent (several tens or hundreds of kilometres) and fairly considerable vertical extent (several hundreds or thousands of metres). In the most complete case, three superposed parts can be distinguished: (a) An upper part, composed wholly or mainly of ice crystals, (b) A middle part, composed of a mixture of ice crystals, snow crystals or snowflakes and supercooled water droplets, (c) A lower part, composed wholly or mainly of ordinary or supercooled water droplets or drops. Sometimes the cloud may consist of only two parts, either: 1) An upper part like (a) above and a lower part like (c) or, 2) An upper part like (b) and a lower part like (c). Less frequently, the entire cloud may also be like (a) or like (b) alone. envoCloudAtlas water-based cloud middle atmospheric level laminar