Clouds and Rain
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Evaporation of water from the oceans lakes and rivers by the heat of the sun is a continuous process. Air contain water bayou is lighter than the air and so it continues to rise up. At considerable height where the temperature is lower the water vapor condenses to form tiny droplets that look like smoke. It is called cloud.
Clouds are of various appearances and shapes and exist at different heights. On the basis of these features they are classified into there main groups. These groups include ten types of clouds.
These are formed at a height up to 2.5 km. they include the stratus like dark gray sheet, the cumulus wooly bunch the cumulonimbus heavy dark woolly the nimbostratus gray rainy and the stratocumulus gray white layered woolly.
They are formed at a height of 2.5 km to 4.5 km. this category includes the construes white wooly sheets of layers and altocumulus white wooly.
These are formed at a height above 4.5 km. they include the cirrus white parches the cirrocumulus where layered patchy woolly and the cirrostratus transparent fibrous thin white veil.
Clouds give us life giving rains and snow fall which helps us to cultivate our land for agriculture.
The sun heat is constantly causing evaporation of water from rivers, lake oceans and other bodies of water. The water vapors are always present in the air. As the air rises it cools and cannot hold much water vapor. At a temperature called the dew point the water vapor condenses on tiny particles of soot dust and salt in the air forming tiny water droplets. The water droplets combine together forming clouds or fog. With further cooling the water droplets combine and gain weight. They fall to the ground due to gravity as rain drops.
Rain is caused only after the humid air rises up and condenses. The upward movement may take place in several ways. When the humid air rises upward after striking against some natural barrier like a mountain and causes rainfall. It is known as aerographic rainfall. In this type of rainfall the windward slope of a mountain range gets more rain. When the warm and humid air masses converge with the cool air masses they cause stormy conditions resulting in condensation and rainfall. This kind of rainfall is known as cyclonic rainfall. The third kind of rainfall is caused by convectional ascent of the warm and humid air. As the humid air rises up, it expands and cools followed by condensation and rainfall. It is known as convectional rainfall.
Rainfall is measured by means of an instrument called rain gauge. Cherrapunji in Assam has been recorded to have the rainfall in the world. Here the average the average annual rainfall went up to 217.5 cams which is a record itself.