Rain is a type of precipitation, a product of the condensation of atmospheric water vapor that is released on the Earth's surface. Nature, in the broadest sense is equivalent to the natural world, physical universe, material world or material universe. The weather is a set of all the phenomena occurring in a given Atmosphere at a given Time. A season is one of the major divisions of the Year, generally based on yearly periodic changes in Weather. Spring is one of the four Temperate Seasons Spring marks the transition from Winter into Summer. Summer is one of the four Temperate Seasons Summer marks the warmest time of year with the longest days Autumn (also known as fall in North American English) is one of the four Temperate Seasons Autumn marks the transition from Summer Winter is one of the four Seasons of Temperate zones Calculated astronomically, it begins on the Solstice and ends on the Equinox The Tropics are centered on the Equator and limited in Latitude by the Tropic of Cancer in the northern hemisphere at approximately 23°26' (23 The dry season is a term commonly used when describing the weather in the Tropics. A wet season or rainy season is a Season in which the average Rainfall in a region is significantly increased A storm is any disturbed state of an astronomical body's atmosphere, especially affecting its surface and strongly implying Severe weather. A tornado is a violent rotating column of air which is in contact with both the surface of the earth and a Cumulonimbus cloud or in rare cases the base of a Cumulus A tropical cyclone is a storm system characterized by a low pressure center and numerous Thunderstorms that produce strong winds and Flooding Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of Cyclones defined as synoptic scale low A winter storm is an event in which the dominant varieties of precipitation are forms that only occur at cold Temperatures such as Snow or A blizzard is a severe Winter storm condition characterized by low Temperatures strong Winds and heavy blowing Snow Blizzards are formed when An ice storm is a type of Winter storm characterized by Freezing rain. In Meteorology, precipitation (also known as one class of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric Fog is a cloud that is in contact with the ground Stratus clouds are usually the only clouds that touch the ground Drizzle (also called mizzle) is light precipitation consisting of liquid water drops smaller than that of Rain, and generally smaller than 0 Freezing rain is a type of precipitation that begins as Snow at higher altitude falling from a Cloud towards earth melts completely on its way down while passing Ice pellets are a form of precipitation consisting of small Translucent ice balls Hail is a form of precipitation which consists of balls or irregular lumps of ice (hailstones "Snowfall" redirects here For other uses see Snow (disambiguation or Snowfall (disambiguation. Graupel (also called snow pellets) refers to precipitation that forms when supercooled Droplets of Water condense on a Snowflake forming This is a list of meteorology topics. The terms relate to Meteorology, the Interdisciplinary scientific study of the atmosphere that focuses on Meteorology (from Greek grc μετέωρος metéōros, "high in the sky" and grc -λογία -logia) is the Interdisciplinary Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location Climate encompasses the temperatures humidity rainfall atmospheric particle count and numerous other meteorogical factors in a given region over long periods of Air pollution is the human introduction into the atmosphere of Chemicals Particulate matter, or Biological materials that cause harm or discomfort In Meteorology, precipitation (also known as one class of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric It forms when separate drops of water fall to the Earth from clouds. A drop or droplet is a small volume of Liquid, bounded completely or almost completely by Free surfaces Surface tension Water is a common Chemical substance that is essential for the survival of all known forms of Life. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 A cloud is a visible mass of droplets or frozen crystals floating in the atmosphere above the surface of the Earth or another Planetary body Not all rain reaches the surface; some of it evaporates while falling through dry air. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five When none of it reaches the ground, it is called virga, a phenomenon often seen in hot, dry desert regions. In Meteorology, virga is an observable streak or shaft of precipitation that falls from a Cloud but evaporates before reaching the ground A desert is a Landscape or region that receives very little precipitation. The METAR code for rain is RA. METAR (METeorological Aviation Report is a format for reporting Weather information

Formation

Rain plays a role in the hydrologic cycle in which moisture from the oceans evaporates, condenses into drops, precipitates (falls) from the sky, and eventually returns to the ocean via rivers and streams to repeat the cycle again. The Earth 's Water is always in movement and the water cycle, also known as the hydrologic cycle, describes the continuous movement of water on above An ocean (from Greek, ''Okeanos'' (Oceanus) is a major body of saline water, and a principal component of the Hydrosphere. "Riverine" redirects here For the use of that term in Maritime geography, see there A stream is a body of Water with a current, confined within a bed and stream-banks The water vapor from plant respiration also contributes to the moisture in the atmosphere. General properties of water vapor Evaporation/sublimation Whenever a water molecule leaves a surface it is said to have evaporated

A major scientific explanation of how rain forms and falls is called the Bergeron process. The Bergeron Findeisen Process (after Tor Bergeron and W Findeisen is the formation of precipitation in the cold clouds of the mid and upper latitudes by ice crystal More recent research points to the influence of Cloud condensation nuclei released as the result of biological processes. Cloud condensation nuclei or CCN s (also known as cloud seeds) are small particles (typically 0

Human influence

A view of rain falling on a street of Kolkata, India. India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country

A torrential downpour in Ballina, Australia. For a topic outline on this subject see List of basic Australia topics.

The fine particulate matter produced by car exhaust and other human sources of pollution form cloud condensation nuclei, leads to the production of clouds and increases the likelihood of rain. Cloud condensation nuclei or CCN s (also known as cloud seeds) are small particles (typically 0 As commuters and commercial traffic cause pollution to build up over the course of the week, the likelihood of rain increases: it peaks by Saturday, after five days of weekday pollution has been built up. In heavily populated areas that are near the coast, such as the United States' Eastern Seaboard, the effect can be dramatic: there is a 22% higher chance of rain on Saturdays than on Mondays. The East Coast of the United States, also known as the "Eastern Seaboard" or "Atlantic Seaboard" refers to the easternmost coastal states in the central and northern ^[1]

Classifying the amount of rain

When classified according to amount of precipitation, rain can be divided into:^[2]

• Very light rain — when the precipitation rate is < 0. 25 mm/hour
• Light rain — when the precipitation rate is between 0. 25 mm/hour - 1. 0 mm/hour
• Moderate rain — when the precipitation rate is between 1. 0 mm/hour - 4. 0 mm/hour
• Heavy rain — when the precipitation rate is between 4. 0 mm/hour - 16. 0 mm/hour
• Very heavy rain — when the precipitation rate is between 16. 0 mm/hour - 50 mm/hour
• Extreme rain — when the precipitation rate is > 50. 0 mm/hour

Properties

Inverted images of the Golden Gate Bridge refracted through raindrops

Falling raindrops are often depicted in popular culture as "teardrop-shaped" — round at the bottom and narrowing towards the top — but this is incorrect. The Golden Gate Bridge is a suspension Bridge spanning the Golden Gate, the opening of the San Francisco Bay onto the Pacific Ocean Only drops of water dripping from some sources are tear-shaped at the moment of formation. Small raindrops are nearly spherical. "Globose" redirects here See also Globose nucleus. A sphere (from Greek σφαίρα - sphaira, "globe Larger ones become increasingly flattened on the bottom, like hamburger buns; very large ones are shaped like parachutes. A hamburger (or burger) is a Sandwich consisting of a cooked ground Meat Patty, usually Beef, placed in a sliced bun or between A parachute is a device used to slow the motion of an object through an atmosphere by creating drag. ^[3] The shape of raindrops was studied by Philipp Lenard in 1898. Philipp Eduard Anton von Lénárd ( June 7, 1862 &ndash May 20, 1947) was a German physicist and the winner of the He found that small raindrops (less than about 2 mm diameter) are approximately spherical. As they get larger (to about 5 mm diameter) they become more doughnut shaped. Beyond about 5 mm they become unstable and fragment. On average, raindrops are 1 to 2 mm in diameter. The biggest raindrops on Earth were recorded over Brazil and the Marshall Islands in 2004 — some of them were as large as 10 mm. |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld The Marshall Islands, officially the Republic of the Marshall Islands (RMI is a Micronesian nation of islands in the middle of the Pacific Ocean The large size is explained by condensation on large smoke particles or by collisions between drops in small regions with particularly high content of liquid water. Smoke is the collection of airborne solid and liquid Particulates and Gases ref> ''Smoke Production and Properties'' - SFPE Handbook of Fire Protection Engineering

Distant rain

Raindrops impact at their terminal velocity, which is greater for larger drops. A free falling object achieves its terminal velocity when the downward force of gravity ( Fg)equals the upward force of drag ( Fd) At sea level and without wind, 0. 5 mm drizzle impacts at about 2 m/s, while large 5 mm drops impact at around 9 m/s. Drizzle (also called mizzle) is light precipitation consisting of liquid water drops smaller than that of Rain, and generally smaller than 0 ^[4] The sound of raindrops hitting water is caused by bubbles of air oscillating underwater. See droplet's sound. A drop or droplet is a small volume of Liquid, bounded completely or almost completely by Free surfaces Surface tension

Generally, rain has a pH slightly under 6. pH is the measure of the acidity or alkalinity of a Solution. This is because atmospheric carbon dioxide dissolves in the droplet to form minute quantities of carbonic acid, which then partially dissociates, lowering the pH. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single Carbonic acid (ancient name acid of air or aerial acid) has the formula H2CO3 In some desert areas, airborne dust contains enough calcium carbonate to counter the natural acidity of precipitation, and rainfall can be neutral or even alkaline. Calcium carbonate is a Chemical compound with the Chemical formula Ca[[Carbon C]] O 3 In Chemistry, an alkali (from Arabic: Al-Qaly القلي القالي) is a basic, ionic salt of an Alkali metal Rain below pH 5. 6 is considered acid rain. Acid rain is Rain or any other form of precipitation that is unusually Acidic It has harmful effects on plants aquatic animals and infastructure

Effect on agriculture

Precipitation, especially rain, has a dramatic effect on agriculture. In Meteorology, precipitation (also known as one class of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric Agriculture refers to the production of goods through the growing of plants and fungi and the raising of domesticated Animals The study of agriculture All plants need at least some water to survive, therefore rain (being the most effective means of watering) is important to agriculture. Plants are living Organisms belonging to the kingdom Plantae. Agriculture refers to the production of goods through the growing of plants and fungi and the raising of domesticated Animals The study of agriculture While a regular rain pattern is usually vital to healthy plants, too much or too little rainfall can be harmful, even devastating to crops. Plants are living Organisms belonging to the kingdom Plantae. Drought can kill crops in massive numbers, while overly wet weather can cause disease and harmful fungus. A drought is an extended period of months or years when a region notes a deficiency in its water supply A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ Plants need varying amounts of rainfall to survive. Plants are living Organisms belonging to the kingdom Plantae. For example, cacti need small amounts of water while tropical plants may need up to hundreds of inches of rain per year to survive. A cactus (plural cacti) is any member of the Spine plant family Cactaceae, native to the Americas

Agriculture of all nations at least to some extent is dependent on rain. Indian agriculture, for example, (which accounts for 25 percent of the GDP and employs 70 percent of the nation's population) is heavily dependent on the rains, especially crops like cotton, rice, oilseeds and coarse grains. India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country Agriculture refers to the production of goods through the growing of plants and fungi and the raising of domesticated Animals The study of agriculture Cotton is a soft staple Fibre that grows around the seeds of the cotton plant ( Gossypium sp Rice is a Cereal foodstuff which forms an important part of the diet of many people worldwide and as such it is a staple food for many A delay of a few days in the arrival of the monsoon can, and does, badly affect the economy, as evidenced in the numerous droughts in India in the 90s. India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country

Culture

Cultural attitudes towards rain differ across the world. In the largely temperate Europe, rain metaphorically has a sad and negative connotation — reflected in children's rhymes like Rain Rain Go Away — in contrast to the bright and happy sun. "Rain Rain Go Away" is a short children's rhyme. As with many Nursery rhymes the origin and meaning of this one is open for debate but one theory The Sun (Sol is the Star at the center of the Solar System. Though the traditional notion of rain in the Western World is negative, rain can also bring joy, as some consider it to be soothing or enjoy the aesthetic appeal of it. In dry places, such as parts of Africa, Australia, India, and the Middle East, rain is greeted with euphoria. For a topic outline on this subject see List of basic Australia topics. India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country The Middle East is a Subcontinent with no clear boundaries often used as a synonym to Near East, in opposition to Far East. (In Botswana, the Setswana word for rain, "pula," is used as the name of the national currency, in recognition of the economic importance of rain in this desert country. The Republic of Botswana (Lefatshe la Botswana is a Landlocked nation in Southern Africa. Tswana ( Setswana) is a Bantu language written in the Latin Alphabet. The pula is the Currency of Botswana. It has the ISO 4217 code BWP and is subdivided into 100 thebe. )

Rain on an umbrella from passing showers

Several cultures have developed means of dealing with rain and have developed numerous protection devices such as umbrellas and raincoats, and diversion devices such as gutters and storm drains that lead rains to sewers. "Parasol" redirects here For other uses see Umbrella (disambiguation, Umbrella (song or Parasol (disambiguation A raincoat is a Waterproof or Water-resistant Coat worn to protect the body from Rain. A rain gutter (also known as eaves trough, guttering or simply as a gutter) is a narrow channel or trough forming the component of a Roof system A storm drain, storm sewer ( US) stormwater drain ( Australia and New Zealand) or surface water system ( UK) Many people also prefer to stay inside on rainy days, especially in tropical climates where rain is usually accompanied by thunderstorms or is extremely heavy (as in a monsoon). A monsoon is a seasonal prevailing wind which lasts for several months Rain may be harvested, though rainwater is rarely pure (as acid rain occurs naturally), or used as greywater. Rainwater harvesting is the gathering or accumulating and storing of rainwater Acid rain is Rain or any other form of precipitation that is unusually Acidic It has harmful effects on plants aquatic animals and infastructure Greywater, also known as sullage, is non-industrial wastewater generated from domestic processes such as dish washing Excessive rain, particularly after a dry period that has hardened the soil so that it cannot absorb water, can cause floods. A flood is an overflow of an expanse of water that submerges land a deluge

Many people find the scent during and immediately after rain especially pleasant or distinctive. The source of this scent is petrichor, an oil produced by plants, then absorbed by rocks and soil, and later released into the air during rainfall. "Smell of rain" redirects here For the Mortiis album see The Smell of Rain. Light or heavy rain is sometimes seen as romantic.

World

Europe

In the United Kingdom most rain is driven into the country by the south-western trade winds following the warm gulf stream currents. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located The Gulf Stream, together with its northern extension towards Europe the North Atlantic Drift, is a powerful warm and swift Atlantic Ocean current that Areas along the western coasts can receive between 1000 mm (40 inches, at sea-level) and 2500 mm (100 inches, on the mountains) of rain per year. However, what is less well known is that the eastern and southern half of the country is much drier, with the south east having a lower rainfall average than Jerusalem and Beirut at between 450 and 600 mm per year. Jerusalem (יְרוּשָׁלַיִם, he-Latn Yerushaláyim; Arabic: ar القُدس, ar-Latn al-Quds) is the Beirut (بيروت Bayrūt) is the Capital and Largest city of Lebanon with a population of over 2

Meanwhile, Bergen in Norway is one of the more famous European rain-cities with its yearly precipitation of 2250 mm (88 inches) on average. is the second largest city in Norway. It is located on the south-western coast of Norway in the county of Hordaland in between a group of mountains known as De syv fjell

North America

One city that is known for rain is Seattle, Washington. Rain is common in the winter, but mostly the climate is cloudy with little rain. Seattle's average rainfall is 942 mm (37. 1 inches) per year,^[5] less than New York City's 1173 mm (46. 2 inches),^[6] but Seattle has 201 cloudy days per year, compared to 152 in New York. Seattle's neighbor to the south, Portland, Oregon, gets more rain with an average of 45 inches (1,100 mm) a year. Portland is a city located in the Northwestern United States, near the Confluence of the Willamette and Columbia rivers ^[7] However, it should be noted that Seattle lies in the rain shadow of the nearby Olympic Mountains, with some locations on the windward sides of the mountains receiving close to 130 inches per year. For the Australian television series see Rain Shadow (TV series. The Olympic Mountains are a Mountain range on the Olympic Peninsula of western Washington in the United States. Windward is the direction from which the wind is blowing at the time in question ^[8] The wettest city in the continental United States is Mobile, Alabama, which average 67 inches of rainfall per year. ^[9] Ketchikan Alaska and other locations in the temperate rainforest of southeast Alaska get an average of 160 inches of rain a year,^[10] sometimes receiving over 200 inches in a year.

Australia

Although Australia is the world's driest continent, Mount Bellenden Ker in the north-east of the country records an average of 8000 mm (315 inches) per year, with over 12000 mm (472 inches) of rain recorded in the year 2000. For a topic outline on this subject see List of basic Australia topics. A continent is one of several large Landmasses on Earth. They are generally identified by Convention rather than any strict criteria with seven regions Mount Bellenden Ker (1593 m/5225 ft is the second highest Mountain in Queensland, Australia. ^[11]

Melbourne has a similar reputation to Vancouver's. Melbourne ( is the second most populous city in Australia, with a Metropolitan area population of approximately 3 In the popular imagination it is thought of as being much rainier than Sydney; however, Sydney receives an average of 1094 mm (43. Sydney (ˈsɪdniː is the most populous city in Australia, with a Metropolitan area population of approximately 4 1 inches) of rain per year compared to Melbourne's 544 mm (21. 4 inches). Sydney, meanwhile, experiences 53 fewer overcast days per year than Melbourne. ^[12][13]

Asia

Cherrapunji, situated on the southern slopes of the Eastern Himalaya in Shillong, India is one of the wettest places on Earth, with an average annual rainfall of 11,430 mm (450 in). Cherrapunji (also spelled as Cherrapunjee) is a town in East Khasi Hills district in the Indian state of Meghalaya. Shillong ( Khasi Shillong ( Hindi: शिलांग Bengali: শিলং is the capital of Meghalaya, one of the smallest states in India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country The highest recorded rainfall in a single year was 22,987 mm (904. 9 inches) in 1861.

A panorama showing a rain cloud on the right

Mythology

The Ancient Greeks believed that rain was a sign of the gods' anger towards them. They thought that it symbolised drowning and frustration as it often disturbed what they were doing.

See also

• Acid rain
• Basic precipitation
• Cherrapunji
• Cloud
• Johad
• Mawsynram
• Meltwater
• Raining animals
• Rain dancing
• Rain sensor
• Red rain in Kerala
• Sanitary sewer overflow
• Water cycle
• Water resources
• Weather

References

External links

• What are clouds, and why does it rain?
• BBC article on the weekend rain effect
• BBC article on rain-making
• Do we have enough fresh water? Johan Rockstrom says we do, if we use it correctly. Earth & Sky interview, discusses capturing rainfall and reducing runoff, partly through conservation tillage.