How are clouds formed?

Answer 1

Clouds are formed when water vapour in the air is cooled and condenses as part of the water cycle. Clouds consist of billions of tiny water droplets (and even ice crystals) floating in the sky and appear in a variety of shapes and sizes depending on how and where they formed. However, there are three main types of cloud:

Cirrus

– high-level, wispy clouds. The name originates from the Latin word meaning "curl cirrus cloudof hair". These feathery clouds form very high up in the sky (at altitudes between 5 km and 14 km) where it is very cold. They are therefore made up of tiny ice crystals rather than water droplets. Cirrus clouds occur in warm air which is being slowly lifted over a large area by an approaching cold front, and they are therefore often the signal of bad weather.


mares tails


Mare’s tails – cirrus clouds are often called mare’s tails. This is because strong winds high in the air blow them into wispy curls like the tail of a horse.

Cumulus

– fluffy, cumulus clouds are named after the word "heap". These are the most familiarcumulus cloud clouds and look like heaps of cotton wool or large cauliflower’s. Cumulus clouds are found at a height of about 500 metres and are composed of tiny water droplets. They form when sunshine warms pockets of moist air and causes them to rise quickly. As they get higher, the pocket of air billows out and forms the familiar fluffy shape as the moist air cools and condenses into water droplets. These clouds are usually seen in fine weather, when the sky is blue.
Stratus...


Stratus

– low-level blankets of cloud. The name "stratus" means "layers" in Latin, although stratus cloudyou in fact rarely see the layers in stratus clouds. Instead they appear as a grey, shapeless sheet of cloud extending in all directions across the sky. They are usually only about 1 km thick, but can be as much as 1000 km wide. Stratus clouds build up when a layer of warm, moist air rises slowly over a mass of colder air. These clouds are often dark and gloomy, and are associated with rain and drizzle. Stratus clouds can sometimes rest on the ground or sea instead of up in the air, and they are then called ‘fog’.


Although there are only three basic types of cloud – cirrus, cumulus and stratus – these can combine to produce other types, such as cumulonimbus, cirrostratus and stratocumulus. In all there are about ten different varieties, which we will explore in more detail in the next section. top of page

Cloud Formation

We know that clouds form when rising air cools and the moisture in it condenses to form water droplets. But do you know what makes the air rise in the first place? Let me tell you.


Air rises for three main reasons:

sun



cold front


* Sunshine – heat from the sun or warm ground warms the air and makes it lighter. It therefore rises into the sky.

* The terrain – air may rise as it is forced upwards due to changes in the terrain (landscape). This often occurs when wind blows air either over mountains, or over cliffs onto land from the sea.

* A front – air can also rise at a weather front. At cold fronts, cold air is pushed under warm air, forcing it upwards and at a warm front, warm moist air is forced up and over the cold air.

In all three of these cases, the warm moist air will cool as it rises, and so the moisture it contains will condense into water droplets – forming clouds.

Answer 2

A cloud is a visible mass of condensed droplets or frozen crystals suspended in the atmosphere above the surface of the Earth or another planetary body. The branch of meteorology in which clouds are studied is nephology.

Clouds form when the invisible water vapour in the air condenses into visible water droplets or ice crystals. This can happen in three ways:

1. The air is cooled below its saturation point. This happens when the air comes in contact with a cold surface or a surface that is cooling by radiation, or the air is cooled by adiabatic expansion (rising). This can happen:

along warm and cold fronts (frontal lift)
where air flows up the side of a mountain and cools as it rises higher into the atmosphere (orographic lift)
by the convection caused by the warming of a surface by insolation (diurnal heating)
when warm air blows over a colder surface such as a cool body of water.
2. Clouds can be formed when two air masses below saturation point mix. Examples are breath on a cold day, aircraft contrails and Arctic sea smoke.

3. The air stays the same temperature but absorbs more water vapor into it until it reaches saturation point

The water in a typical cloud can have a mass of up to several million tonnes. However, the volume of a cloud is correspondingly high, and the net density of the relatively warm air holding the droplets is low enough that air currents below and within the cloud are capable of keeping it suspended.

Answer 3

A cloud is composed of millions of little droplets of water (or ice crytals when temperature is very low) suspended in the air. Hence a cloud can form when water vapor becomes liquid, i.e. when the humid air is cooled and condenses on tiny particles. There are several major processes for cloud formation.
Convection is one of the processes that allows cloud formation. When the sun shines, the air at the ground level that contain water vapor is heated and it begins to rise, and as the air rises, it begins to cool. Clouds are formed when the humid air is cooled below a critical temperature : the water then condenses on tiny suspended particles and forms droplets in the atmosphere.
Clouds can also form because of the Earth's surface topography, mountains or hills for example. They are then called "orographic clouds".The air is forced to move over the mountain, and as it ascends, the air cools. If it cools to it's saturation point, condensation occurs and the water contained within the air becomes visible as a cloud.
Precipitation is the name of water that falls out of clouds: it can be rain, or snow, or hail...

In some clouds the tiny water droplets come together by collision to make bigger drops. As the drops become bigger and bigger (volume increases about a million times) they become too heavy for the air to support and they fall as rain.
Clouds with surrounding air temperature below 0°C are made of ice crystals. These ice crystals that are formed near droplets of super-cooled water (water that remains as liquid even below 0°C), increase in size when water vapour from cloud droplets is deposited on the ice crystals. As the ice crystals fall, they may collide and this makes the ice crystals heavier. When the ice crystals are too heavy to float in the air, it will fall to the ground. The crystals become snow, or raindrops if they fall through air that is hotter than 0°C.
You know now that as the water evaporates, vapors rise, cool and condense into clouds. The clouds move over the land, and precipitation falls. The water fills lakes, streams and rivers, and eventually flows back into the oceans where evaporation starts the process anew. Water can also penetrate into the soil (11% of the water). Another process is also important in the water cycle, that is transpiration by plant leaves: as plants absorb water from the soil, the water moves from the roots through the stems to the leaves, where it can evaporate.

Answer 4

How Are Clouds Created

Answer 5

Condensation or deposition of water above the Earth's surface creates clouds. In general, clouds develop in any air mass that becomes saturated (relative humidity becomes 100 %). Saturation can occur by way of atmospheric mechanisms that cause the temperature of an air mass to be cooled to its dew point or frost point. The following mechanisms or processes can achieve this outcome causing clouds to develop:

(1). Orographic uplift occurs when air is forced to rise because of the physical presence of elevated land. As the parcel rises it cools as a result of adiabatic expansion at a rate of approximately 10° Celsius per 1000 meters until saturation. The development of clouds and resulting heavy quantities of precipitation along the west coast of Canada are mainly due to this process.
(2). Convectional lifting is associated with surface heating of the air at the ground surface. If enough heating occurs, the mass of air becomes warmer and lighter than the air in the surrounding environment, and just like a hot air balloon it begins to rise, expand, and cool. When sufficient cooling has taken place saturation occurs forming clouds. This process is active in the interior of continents and near the equator forming cumulus clouds and or cumulonimbus clouds (thunderstorms). The rain that is associated with the development of thunderstorm clouds is delivered in large amounts over short periods of time in extremely localized areas.

(3). Convergence or frontal lifting takes place when two masses of air come together. In most cases, the two air masses have different temperature and moisture characteristics. Oneof the air masses is usually warm and moist, while the other is cold and dry. The leading edge of the latter air mass acts as an inclined wall or front causing the moist warm air to be lifted. Of course the lifting causes the warm moist air mass to cool due to expansion resulting in saturation. This cloud formation mechanism is common at the mid-latitudes where cyclones form along the polar front and near the equator where the trade winds meet at the intertropical convergence zone.

(4). Radiative cooling occurs when the sun is no longer supplying the ground and overlying air with energy derived from solar insolation (e.g., night). Instead, the surface of the Earth now begins to lose energy in the form of longwave radiation which causes the ground and air above it to cool. The clouds that result from this type of cooling take the form of surface fog.

Answer 6

Moisture evaporating from the earth/land, elevates and collects in the atmosphere, forming the white clouds we see or fog. The more that evaporates, the darker the clouds get until they are so full of water, they rain it back down again. Good question!!!

Answer 7

Water in earth surface evaporates into vapour. As water vapour is lighter than air they travel up into atmosphere and form as a cloud when condensed with atmospheric dust particles and other gases available over there. Now a cloud is formed as a floating substance.

Answer 8

sunlight motives water to evaporate into the ambience. This air containing the water vapor is heated on the outdoors of the earth and rises. because it rises, it cools and the water vapor condenses on some form of particulate count number mutually with airborne dirt and dirt, ash, or smoke to style clouds. decrease clouds encompass water droplets and better clouds encompass ice debris. greater humidity leads to extra cloud formation.

Answer 9

Clouds form when the invisible water vapour in the air condenses into visible water droplets or ice crystals. This can happen in three ways:

1. The air is cooled below its saturation point. This happens when the air comes in contact with a cold surface or a surface that is cooling by radiation, or the air is cooled by adiabatic expansion (rising). This can happen:

along warm and cold fronts (frontal lift)
where air flows up the side of a mountain and cools as it rises higher into the atmosphere (orographic lift)
by the convection caused by the warming of a surface by insolation (diurnal heating)
when warm air blows over a colder surface such as a cool body of water.
2. Clouds can be formed when two air masses below saturation point mix. Examples are breath on a cold day, aircraft contrails and Arctic sea smoke.

3. The air stays the same temperature but absorbs more water vapor into it until it reaches saturation point.

The water in a typical cloud can have a mass of up to several million tonnes. However, the volume of a cloud is correspondingly high, and the net density of the relatively warm air holding the droplets is low enough that air currents below and within the cloud are capable of keeping it suspended. As well, conditions inside a cloud are not static: water droplets are constantly forming and re-evaporating. A typical cloud droplet has a radius on the order of 1 x 10-5 m and a terminal velocity of about 1-2 cm/s. This gives these droplets plenty of time to re-evaporate as they fall into the warmer air beneath the cloud.


Cumulonimbus cloudMost water droplets are formed when water vapor condenses around a condensation nucleus, a tiny particle of smoke, dust, ash, or salt. In supersaturated conditions, water droplets may act as condensation nuclei.

The growth of water droplets around these nuclei in supersaturated conditions is given by the Mason equation.

Water droplets large enough to fall to the ground are produced in two ways. The most important means is through the Bergeron Process, theorized by Tor Bergeron, in which supercooled water droplets and ice crystals in a cloud interact to produce the rapid growth of ice crystals; these crystals precipitate from the cloud and melt as they fall. This process typically takes place in clouds with tops cooler than -15°C. The second most important process is the collision and wake capture process, occurring in clouds with warmer tops, in which the collision of rising and falling water droplets produces larger and larger droplets, which are eventually heavy enough to overcome air currents in the cloud and the updraft beneath it and fall as rain. As a droplet falls through the smaller droplets which surround it, it produces a "wake" which draws some of the smaller droplets into collisions, perpetuating the process. This method of raindrop production is the primary mechanism in low stratiform clouds and small cumulus clouds in trade winds and tropical regions and produces raindrops of several millimeters diameter.


This wave cloud pattern formed off of the Île Amsterdam in the far southern Indian OceanThe actual form of cloud created depends on the strength of the uplift and on air stability. In unstable conditions convection dominates, creating vertically developed clouds. Stable air produces horizontally homogeneous clouds. Frontal uplift creates various cloud forms depending on the composition of the front (ana-type or kata-type warm or cold front). Orographic uplift also creates variable cloud forms depending on air stability, although cap cloud and wave clouds are specific to orographic clouds

Answer 10

Clouds form when the invisible water vapour in the air condenses into visible water droplets or ice crystals. This can happen in three ways:

1. The air is cooled below its saturation point. This happens when the air comes in contact with a cold surface or a surface that is cooling by radiation, or the air is cooled by adiabatic expansion (rising). This can happen:

along warm and cold fronts (frontal lift)
where air flows up the side of a mountain and cools as it rises higher into the atmosphere (orographic lift)
by the convection caused by the warming of a surface by insolation (diurnal heating)
when warm air blows over a colder surface such as a cool body of water.
2. Clouds can be formed when two air masses below saturation point mix. Examples are breath on a cold day, aircraft contrails and Arctic sea smoke.

3. The air stays the same temperature but absorbs more water vapor into it until it reaches saturation point.

The water in a typical cloud can have a mass of up to several million tonnes. However, the volume of a cloud is correspondingly high, and the net density of the relatively warm air holding the droplets is low enough that air currents below and within the cloud are capable of keeping it suspended. As well, conditions inside a cloud are not static: water droplets are constantly forming and re-evaporating. A typical cloud droplet has a radius on the order of 1 x 10-5 m and a terminal velocity of about 1-2 cm/s. This gives these droplets plenty of time to re-evaporate as they fall into the warmer air beneath the cloud.


Cumulonimbus cloudMost water droplets are formed when water vapor condenses around a condensation nucleus, a tiny particle of smoke, dust, ash, or salt. In supersaturated conditions, water droplets may act as condensation nuclei.

The growth of water droplets around these nuclei in supersaturated conditions is given by the Mason equation.

Water droplets large enough to fall to the ground are produced in two ways. The most important means is through the Bergeron Process, theorized by Tor Bergeron, in which supercooled water droplets and ice crystals in a cloud interact to produce the rapid growth of ice crystals; these crystals precipitate from the cloud and melt as they fall. This process typically takes place in clouds with tops cooler than -15°C. The second most important process is the collision and wake capture process, occurring in clouds with warmer tops, in which the collision of rising and falling water droplets produces larger and larger droplets, which are eventually heavy enough to overcome air currents in the cloud and the updraft beneath it and fall as rain. As a droplet falls through the smaller droplets which surround it, it produces a "wake" which draws some of the smaller droplets into collisions, perpetuating the process. This method of raindrop production is the primary mechanism in low stratiform clouds and small cumulus clouds in trade winds and tropical regions and produces raindrops of several millimeters diameter.


This wave cloud pattern formed off of the Île Amsterdam in the far southern Indian OceanThe actual form of cloud created depends on the strength of the uplift and on air stability. In unstable conditions convection dominates, creating vertically developed clouds. Stable air produces horizontally homogeneous clouds. Frontal uplift creates various cloud forms depending on the composition of the front (ana-type or kata-type warm or cold front). Orographic uplift also creates variable cloud forms depending on air stability, although cap cloud and wave clouds are specific to orographic clouds.