GeoMag

T H E L AY E R S 0 F C L O U D S

RICHARD KING

THE LAYERS OF CLOUDS

The Layers of Clouds Without clouds, we cannot exist. Clouds are fascinating with their different shapes and layers. They are formed from water vapour and are large areas of ice crystals or water droplets. When warm air containing water molecules rises and condenses, some water molecules released and forms clouds that display a colour for us to see. The white that is seen in a cloud is due to the water droplets scattering the rays from the sun. The grey colouring in some clouds is because they have too many water droplets or ice crystals. The clouds appear to ‘float’ because warmer air is lighter than cooler air, so if the cloud is warmer than the air surrounding it, the cloud shall float and move. Clouds can move due to the wind blowing it around as the particles are not stronger than it. Stratus The lowest (up to 2,000 meters above sea level) layer of clouds is the stratus layer. Stratus clouds will most likely be grey or white. During a stable day, the stratus clouds may form from a gentle breeze moving cool, moist air. Depending on the conditions, the clouds can be a variety of densities. The stratus clouds rarely, if ever, cause precipitationll unless the density is extremely high, but they can form a mist or fog as they are the lowest cloud layer. From what we know, the stratus layer can be categorized as: stratus nebulosus (featureless, dark layer that may produce a light drizzle) and stratus fractus (a stratus layer which is starting to or is breaking up or ‘dissipate’). Alto The ‘middle layer’ (anywhere between 2,000 and 5,500 meters) can be known as the ‘alto’ layer. It contains two types of cloud groups: altocumulus and altostratus. Each cloud group has a similar height so that is why they can be categorized as the ‘alto’ layer. Altostratus clouds start as a thin cloud from either a separation or a branch of a veil of gradually thickening cirrostratus clouds. Altostratus clouds are usually grey or blue with few to little features. The sun will usually be unable to shine rays through altostratus clouds and this can cause optical effects like coronas or iridescence. They often form >

Rainbow Tariq Ahmed

16 | Geographical Magazine • Merchant Taylors’ School

2021/22 Edition | 17