Cloud Formation Presented by: Maida Kanwal (17) Hira Sumbal (15) Zunaira Nawaz (21) Sheeren Rehman (31) Um e Laila (09) Aarfa Tufail (11) What are clouds? Clouds: A cloud is a visible mass of liquid droplets or frozen crystals made of water or various chemicals suspended in the atmosphere above the surface of a planetary body. These suspended bodies are called as aerosols. Types of clouds Luke Howard’s Classification: (1803) Luke Howard has been called the Father of Meteorology. He was the first man to classify clouds. World Meteorological Organization (WMO) has extended Luke Howard’s classification to make 10 main groups of clouds. High level clouds • Cirrus. • Cirrocumulus, Cirrostratus. Mild level clouds • Altocumulus. • Altostratus, Nimbostratus. Low level clouds • Stratocumulus, Cumulonimbus. • Stratus, Cumulus. Types of clouds Names for clouds: The names for clouds are usually combinations of the following prefixes or suffixes: Stratus/ Strato = Flat or layered and smooth. Cumulus/ Cumulo = Heaped up or puffy, like cauliflower. Cirrus/ Cirro = High up or wispy. Alto = Medium level. Nimbus/ Nimbo = Rain-bearing cloud. Types of clouds 1- High Level Clouds: Above 20,000 feet, composed of ice crystals, thin and white in appearance. 2- Mild Level Clouds: Between 6000-20,000 feet, composed of water droplets, grey to pale blue in appearance. Types of clouds 3- Low Level Clouds: Below 6,000 feet, composed of water droplets, may contain ice crystals, light grey in appearance. The water cycle The Water Cycle consists of 4 main processes: 1- Evaporation: High temperature cause evaporation of water from water bodies, i.e. Oceans, Rivers, Lakes etc. 2- Transpiration: Transpiration, loss of water from plants, enters water into the the atmosphere. The water cycle 3- Condensation: The air and water droplets condense and clouds are formed. 4- Precipitation: The clouds looses their water in the form of rain, hail, snow. This is how water is returned back to ground and cycle continues. Cloud formation Process: Cloud formation occurs through convection. As the intensity of solar radiation increases, the warmer air becomes lighter and moves upward. As this happens, the temperature decreases, so does the amount of water vapors air can hold. Due to this, the process of condensation starts. These vapors rapidly condense and soon clouds — composed of countless billions of tiny water droplets or ice crystals — result. Clouds are occasionally produced by a reduction of pressure aloft or by the mixing of warmer and cooler air currents. Cloud formation Clouds are formed at different heights. The characteristics of clouds are formed by the elements available, including the amount of water vapors, the temperature at that height, the wind, and the interplay of other air masses. Factors influencing Cloud Formation Factors which influence cloud formation are: Surface heating. Topography forcing. Frontal. Convergence. Turbulence. Factors influencing Cloud Formation Surface Heating: The increase in temperature heats the ground and the air in contact with it which rises and form clouds (Cumulus). Topography: The shape and features of the area - can cause clouds to be formed. When air is forced to rise over a barrier of mountains or hills it cools as it rises resulting in cloud formation. Factors influencing Cloud Formation Frontal: Clouds are formed when a mass of warm air rises up over a mass of cold, dense air over large areas along fronts. Convergence: Streams of air flowing from different directions are forced to rise where they flow together, or converge. Turbulence: A sudden change in wind speed with height creating turbulent eddies in the air. Impact of clouds on Environment Clouds cool Earth's atmosphere by absorbing heat emitted from the surface and radiating it to the space. Clouds help redistribute extra heat from the equator toward the poles. Clouds indicate what type of atmospheric processes are occurring. For Example, Cumulus Clouds indicate surface heating and atmospheric turbulence. Impact of clouds on Environment The reflection of sunlight from different kinds of clouds can cool Earth’s atmosphere. Clouds are required for precipitation and essential for hydrological cycle. Any Questions?