Precipitation: Definition, Process and Types

Precipitation is defined as any process of condensation of atmospheric water vapor that falls beneath the gravitational attraction of clouds in meteorology. Drizzling, rain, sleet, snow, ice pellets, graupel, and hail are the most common types of precipitation. It is a type of chemical reaction wherein the mixing of a precipitate (a solid ionic substance) and two solutions of two different ionic substances takes place. Precipitation is an important part of the water cycle process. In this article, we will have a look at the meaning of precipitation, the many types of precipitation, the method, the categorization, and detailed examples of precipitation.

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What is Precipitation?

Precipitation is defined as any liquid or frozen water that exist in the atmosphere and falls to the Earth's surface. It's a chemical reaction in which two ionic material solutions are combined to generate a solid ionic substance (a precipitate).

Precipitation, for example, occurs when a portion of the atmosphere becomes saturated with water vapor, which then condenses and precipitates when the temperature is just perfect. The cooling of air molecules and the addition of water vapor are the two processes that cause the air to become saturated.

Precipitation

Precipitation includes both heavy and mild rain, as well as snow, drizzle, and hail. Fog and dew, on the other hand, do not come within the category of precipitation. It's because they're both instances of water condensing. Dew condenses on objects and fog condenses in the air.

Furthermore, certain forms of precipitation are associated with summer and others with winter. Snow and graupel are the ones that are linked with winter. Summer, on the other hand, brings rain and hail. Furthermore, other forms of precipitation such as drizzle, sleet, and fog drip are not seasonal.

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Types of Precipitation

Precipitation brings in the deposit of freshwater on our Earth, hence it plays a major role in the water cycle. Depending on the form the water takes place, it is divided into three categories such as:

• Ice

The frozen forms of the water that is precipitated include:

• Graupel
• Hail
• Sleet
• Snow
• Ice Needles

• Liquid Water

In liquid form, the precipitation occurs in the form of:

• Drizzle
• Rain

• Freezing Liquid water when it contacts the surface 

When the liquid forms come into contact with the air mass in the freezing temperature, it transforms into:

• Freezing Drizzle
• Freezing Rain

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Classification of Precipitation

Rain, fog drip, snow, sleet, hail, ice palette, and graupel are the different types of precipitation. They're as discussed below-

Rain

Rain is the most prevalent type of precipitation. It is made up of little water droplets that get heavy enough in the clouds to fall to the earth's surface.

Raindrops can grow up to 6mm in diameter. The process of coalescence occurs when water droplets unite to produce larger water droplets and when water droplets freeze onto an ice crystal. As larger drips fall to the Earth's surface, they break up into smaller drops.

The amount of rain falls in a wide range of sizes, both temporally and spatially. Watershed extremes such as floods and droughts are caused by this fluctuation.

Classification of Precipitation

Snowflakes

Snow is made up of flaky ice crystals with an average density of 0.1g/cc. As the water vapor forces the droplets to evaporate, the crystals might grow in size at the expense of the droplets.

As snowflakes, these drops descend from the atmosphere due to their mass. Temperatures below freezing from the clouds to the ground are favorable for snowfall.

Fog Drip

Water dripping on the ground during fog is known as fog drip. It happens when fog droplets stick to tree needles, leaves, or other objects, consolidate into larger drops, and then fall to the earth. It is a cloud of water vapor that is condensed and suspended in the air near the earth’s surface level.

Hail and Sleet

All of these types of precipitation are extremely similar. Hail is frequently associated with thunderstorms or hot weather. While sleet precipitation is a possibility in cold weather. Sleet is effectively ice balls, while hail is partly frozen rain.

Halt and Sleet

Ice Pellets and Graupel

Ice pellets are microscopic, transparent ice balls that are a form of precipitation. Ice pellets are distinct from graupel, which is a frosty white rime, and a slushy liquid or semisolid mixture of rain and snow.

Ice pellets

In contrast to the dull splat of liquid raindrops, ice pellets typically bounce when they hit the ground or other solid surfaces, and emit a higher-pitched "tap" when impacting objects like jackets, windshields, and dried leaves. Pellets do not form a solid mass unless they are exposed to freezing rain.

Graupel

Graupel, also known as soft hail, corn snow, hominy snow, or snow pellets, is created when supercooled water droplets condense and freeze on falling snowflakes.

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Process of Precipitation

Condensation of water vapors in the air mass causes precipitation. Due to adiabatic cooling, the rising air mass containing a significant number of water vapors becomes saturated. Clouds are formed by the condensation of water vapors. There are updrafts and downdrafts in every cloud.

• The updraft determines the formation and height of the clouds. The higher the cloud rises, the stronger the updraft. The strength of the updraft reduces as the liquid water level rises, whereas the downdraft rises. Precipitation is created as a result.
• Although all clouds contain water, some generate precipitation and others do not. Precipitated moisture drips from the clouds in some situations, but it evaporates in the atmosphere before reaching the earth's surface.
• Precipitation happens only when cloud droplets or ice crystals become large enough to overcome the atmosphere's updrafts. It means that in a cloud from which precipitation falls, some unique mechanisms are in action.
• Although all clouds contain water, some generate precipitation and others do not. Precipitated moisture drips from the clouds in some situations, but it evaporates in the atmosphere before reaching the earth's surface.
• Precipitation happens only when cloud droplets or ice crystals become large enough to overcome the atmosphere's updrafts. 

Process of Precipitation

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Precipitation Mechanisms

The mechanisms inside the cloud can be explained by two different processes:

1. The Bergeron Process- It involves a mixture of ice crystals and super-cooled water droplets in the clouds. An ice crystal colliding with a droplet of super-cooled water causes the droplet to freeze. This method is based on water qualities.
2.  Collision: Coalescence Procedure- This process is appropriate to clouds with a base that does not extend above the freezing point. Warm clouds are the name given to these clouds. These clouds are made up of a vast number of cloud droplets of various sizes. Large drops expand at the expense of smaller ones. As a result, they crash with the caught smaller droplets and become a part of it.

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Categorization of Precipitation

When a moist air mass undergoes the condensation process, precipitation happens. When the air is cooled and saturated with the same amount of moisture, this process occurs. Only when the air mass rises to greater altitudes does this cooling process take place. The air mass can be pushed to higher elevations largely in three ways, each of which produces three distinct types of precipitation: Cyclonic, Convective, and Orographic Precipitation.

• Cyclonic Precipitation- A cyclone is an atmospheric zone with a substantial low pressure and a circular wind motion. The movement of moist air mass to this location is induced by the difference in pressure, resulting in cyclonic precipitation.

There are two forms of cyclonic precipitation: frontal and non-frontal precipitation.

• Frontal Precipitation- The hot wet air mass boundary is referred to as a frontal. The expansion of air at the frontal surface causes this precipitation.
• Non-Frontal Precipitation- This is a moving cold wet air mass boundary that causes precipitation.

Non-Frontal Precipitation

• Convective Precipitation- Some reasons cause the air above the land region to become heated. The majority of this hot air rises cools, and precipitates. Convective precipitation is typically showery. The intensity of this sort of precipitation varies.

Types of Rainfall – Convective Rainfall

• Orographic Precipitation- Moving air masses have the potential to collide with obstacles such as mountains. They rise after striking, generating condensation and precipitation. When compared to the leeward side of the barrier, the windward side of the barrier receives more precipitation.

Orographic Precipitation

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Things to Remember

• Precipitation is defined as any liquid or frozen water that occurs in the atmosphere and falls to the Earth's surface. It's a chemical reaction in which two ionic material solutions are combined to generate a solid ionic substance (a precipitate).
• Rain, fog drip, snow, sleet, hail, ice palette, and graupel are the different types of precipitation.
• Rain is the most prevalent type of precipitation. 
• Snow is made up of flaky ice crystals with an average density of 0.1g/cc. 
• Water dripping on the ground during fog is known as fog drip. 
• Sleet is effectively ice balls, while hail is partly frozen rain.
• Ice pellets are microscopic, transparent ice balls that form as a form of precipitation. 
• Condensation of water vapors in the air mass causes precipitation. Due to adiabatic cooling, the rising air mass containing a significant number of water vapors becomes saturated. 
• The air mass can be pushed to higher elevations largely by three ways, each of which produces three distinct types of precipitation: Cyclonic, Convective and Orographic

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