What is Climate?

Information about Climate


Part of the Nature series on Weather
Seasons
Temperate
• Spring • Summer • • Autumn • Winter •
Tropical
• Dry season • • Wet season
Storms
• Thunderstorm • Tornado • • Tropical Cyclone (Hurricane) • • Winter storm • Blizzard
Precipitation
• Fog • Drizzle • Rain • • Freezing rain • Sleet • • Hail • Snow
Topics
• Meteorology • • Weather forecasting • • Climate • Air pollution •
Project • • [ e]

Climate is the average and variations of weather over long periods of time. Climate zones can be defined using parameters such as temperature and rainfall. Paleoclimatology focuses on ancient climate information derived from sediment found in lake beds, ice cores, as well as various fauna and flora including tree rings and coral. Climate models can be used to determine the amount of climate change anticipated in the future.

Definition

Climate (from Ancient Greek klima) is commonly defined as the weather averaged over a long period of time. The standard averaging period is 30 years but other periods may be used depending on the purpose. Climate also includes statistics other than the average, such as the magnitudes of day-to-day or year-to-year variations. The Intergovernmental Panel on Climate Change (IPCC) glossary definition is:

Climate in a narrow sense is usually defined as the “average weather”, or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. The classical period is 30 years, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system.^[1]

The main difference between climate and everyday weather is best summarized by the popular phrase "Climate is what you expect, weather is what you get."^[2] Over historic time spans there are a number of static variables that determine climate, including: latitude, altitude, proportion of land to water, and proximity to oceans and mountains. Other climate determinants are more dynamic: The thermohaline circulation of the ocean distributes heat energy between the equatorial and polar regions; other ocean currents do the same between land and water on a more regional scale. Degree of vegetation coverage affects solar heat absorption, water retention, and rainfall on a regional level. Alterations in the quantity of atmospheric greenhouse gases determines the amount of solar energy retained by the planet, leading to global warming or global cooling. The variables which determine climate are numerous and the interactions complex, but there is general agreement that the broad outlines are understood, at least insofar as the determinants of historical climate change are concerned.

Climate record

Modern

Instrumental temperature record of the last 150 years

Details of the modern climate record are known through the taking of measurements from such weather instruments as thermometers, barometers, and anemometers during the past few centuries. The instruments used to study weather conditions over the modern time scale, their known error, their immediate environment, and their exposure have changed over the years, which must be considered when studying the climate of centuries past.^[3]

Paleoclimatology

Main article: Paleoclimatology

Paleoclimatology is the study of climate change taken on a longer scale, spanning a greater section of the Earth's history. It uses records from ice sheets, tree rings, sediment, coral, and rocks to determine the past state of the climate system on Earth, and whether or not long term climate cycles exist.^[4]

Climate change

See also: Climate change

Climate change refers to the variation in the Earth's global climate or in regional climates over time. It describes changes in the variability or average state of the atmosphere over time scales ranging from decades to millions of years. These changes can be caused by processes internal to the Earth, external forces (e.g. variations in sunlight intensity) or, more recently, human activities.

In recent usage, especially in the context of environmental policy, the term "climate change" often refers only to changes in modern climate, including the rise in average surface temperature known as global warming. In some cases, the term is also used with a presumption of human causation, as in the United Nations Framework Convention on Climate Change (UNFCCC). The UNFCCC uses "climate variability" for non-human caused variations.^[5]

Earth has undergone periodic climate shifts in the past, including four major ice ages. These consisting of glacial periods where conditions are colder than normal, separated by interglacial periods. The accumulation of snow and ice during a glacial period increases the surface albedo, reflecting more of the Sun's energy into space and maintaining a lower atmospheric temperature. Increases in greenhouse gases, such as by volcanic activity, can increase the global temperature and produce an interglacial. Suggested causes of ice age periods include the positions of the continents, variations in the Earth's orbit, changes in the solar output, and vulcanism.^[6]

Climate models

See also: Climate models

Climate models use quantitative methods to simulate the interactions of the atmosphere, oceans, land surface, and ice. They are used for a variety of purposes from study of the dynamics of the weather and climate system to projections of future climate. All climate models balance, or very nearly balance, incoming energy as short wave (including visible) electromagnetic radiation to the earth with outgoing energy as long wave (infrared) electromagnetic radiation from the earth. Any unbalance results in a change in the average temperature of the earth.

The most talked-about models of recent years have been those relating temperature to emissions of carbon dioxide (see greenhouse gas). These models predict an upward trend in the surface temperature record, as well as a more rapid increase in temperature at higher altitudes.

Models can range from relatively simple to quite complex:

A simple radiant heat transfer model that treats the earth as a single point and averages outgoing energy
this can be expanded vertically (radiative-convective models), or horizontally
finally, (coupled) atmosphere–ocean–sea ice global climate models discretise and solve the full equations for mass and energy transfer and radiant exchange.

• • [ e] Meteorological data and variables
Atmospheric pressure Baroclinity Cloud Convection CAPE CIN Dew point Heat index Humidex Humidity Lifted index Lightning Pot T Precipitation Sea surface temperature Surface solar radiation Surface weather analysis Temperature Theta-e Visibility Vorticity Wind chill Water vapor Wind

References

1. ^ Intergovernmental Panel on Climate Change. Appendix I: Glossary. Retrieved on 2007-06-01.
2. ^ National Weather Service Office Tucson, Arizona. Main page. Retrieved on 2007-06-01.
3. ^ Spencer Weart. The Modern Temperature Trend. Retrieved on 2007-06-01.
4. ^ National Oceanic and Atmospheric Administration. NOAA Paleoclimatology. Retrieved on 2007-06-01.
5. ^ [1]
6. ^ Illinois State Museum (2002). Ice Ages. Retrieved on 2007-05-15.

External links

• • [ e] Climate types under the Kppen climate classification
Class A	Equatorial (Af) Monsoon (Am) Savanna (Aw, As)
Class B	Arid (BWh, BWk) Semi-arid (BSh, BSk)
Class C	Humid subtropical (Cfa, Cwa) Oceanic (Cfb, Cwb, Cfc) Mediterranean (Csa, Csb)
Class D	Humid continental (Dfa, Dwa, Dfb, Dwb) Subarctic (Dfc, Dwc, Dfd) High-altitude Mediterranean (Dsa, Dsb, Dsc)
Class E	Polar (ET, EF) Alpine (ETH)

• • [ e] Elements of nature
Earth	History of Earth Earth science Structure of the Earth Plate tectonics Geological history of Earth Geology
Weather	Climate Earth's atmosphere
Life	Biosphere Origin of life Microbe Plants Fungus Fauna Animals Biology Evolutionary history of life
Environment	Wilderness Ecology Ecosystem
Universe	Matter Energy Extraterrestrial life Outer space
Project

Nature, in the broadest sense, is equivalent to the natural world, physical universe, material world or material universe. "Nature" refers to the phenomena of the physical world, and also to life in general.
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weather is the set of all extant phenomena in a given atmosphere at a given time. The term usually refers to the activity of these phenomena over short periods (hours or days), as opposed to the term climate, which refers to the average atmospheric conditions over longer periods of
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Seasons

Temperate
Spring
Summer
Autumn
Winter
Tropical
Dry
season Cool
Hot
Wet season

A season is one of the major divisions of the year, generally based on yearly periodic changes in weather.
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temperate latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally mild, rather than extreme hot or cold. However, a temperate climate can have very unpredictable weather.
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Seasons

Temperate
Spring
Summer
Autumn
Winter
Tropical
Dry
season Cool
Hot
Wet season

Spring
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Summer is one of the four seasons of the year. In the West, the seasons are generally considered to start at the equies and solstices, based on astronomical reckoning. In English-language calendars, based on astronomy, summer begins on the day of the summer solstice and ends on the
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Autumn (also known as Fall in North American English) is one of the four temperate seasons. Autumn marks the transition from summer into winter. In the northern hemisphere, the start of autumn is generally considered to be around September and in the southern hemisphere, its
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Winter is one of the four seasons of temperate zones. Almost all English-language calendars, going by astronomy, state that winter begins on the winter solstice, and ends on the spring equinox.
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tropics are the geographic region of the Earth centered on the equator and limited in latitude by the Tropic of Cancer in the northern hemisphere, at approximately 23°30' (23.5°) N latitude, and the Tropic of Capricorn in the southern hemisphere at 23°30' (23.5°) S latitude.
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For the 2006 Chadian film, see .

The Dry season is a term commonly used when describing the weather in the tropics. The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over
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A Wet season or rainy season is a season in which the average rainfall in a region is significantly increased. The term green season is also sometimes used as a euphemism by tourist authorities. These terms are commonly used describing the weather in the tropics.
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storm is any disturbed state of an astronomical body's atmosphere, especially affecting its surface, and strongly implying severe weather. It may be marked by strong wind, thunder and lightning (a thunderstorm), heavy precipitation, such as ice (ice storm), or wind transporting
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thunderstorm, also called an electrical storm or lightning storm, is a form of weather characterized by the presence of lightning and its attendant thunder produced from a cumulonimbus cloud.
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tornado is a violently rotating column of air which is in contact with both a cumulonimbus cloud or, in rare cases, a cumulus cloud base and the surface of the earth. Tornadoes come in many sizes but are typically in the form of a visible condensation funnel, whose narrow end
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tropical cyclone is a meteorological term for a storm system characterized by a low pressure system center and thunderstorms that produces strong wind and flooding rain. A tropical cyclone feeds on the heat released when moist air rises and the water vapor it contains condenses.
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winter storm is a meteorological event in which the dominant varieties of precipitation are forms that only occur at cold temperatures, such as snow or sleet, or a rainstorm where ground temperatures are cold enough to allow ice to form (i.e. freezing rain).
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blizzard is a severe winter storm condition characterized by low temperatures, strong winds, and heavy blowing snow. Blizzards are formed when a high pressure system, also known as a ridge, interacts with a low pressure system; this results in the advection of air from the high
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precipitation (also known as hydrometeor) is any product of the condensation of atmospheric water vapor that is deposited on the earth's surface. It occurs when the atmosphere (being a large gaseous solution) becomes saturated with water vapour and the water condenses and
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FOG can be an acronym for...

the tool "Flexible Object Generator"
the tool "Fragmented-Object Generator"
Fiber Optic Gulf - a submarine telecommunications cable linking the United Arab Emirates, Qatar, Bahrain, and Kuwait
Fibre optic gyroscope

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Drizzle is light precipitation consisting of liquid water drops smaller than that of rain, and generally smaller than 0.5 mm (0.02 in.) in diameter.
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Rain is a type of precipitation, a product of the condensation of atmospheric water vapor that is deposited on the earth's surface. It forms when separate drops of water fall to the Earth's surface from clouds.
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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 through a layer of air above freezing temperature, and then
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Sleet is a term used in a variety of ways to describe precipitation intermediate between rain and snow but distinct from hail.
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Hail is a form of precipitation which consists of balls or irregular lumps of ice (hailstones). Hailstones on Earth usually consist mostly of water ice and measure between 5 and 50 millimetres in diameter, with the larger stones coming from severe thunderstorms.
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SNOW 1.0 and 2.0 are two word-based synchronous stream ciphers developed by Thomas Johansson and Patrik Ekdahl at Lund University.

SNOW 1.0, originally simply SNOW, was submitted to the NESSIE project.
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Meteorology (from Greek: μετέωρον, meteoron, "high in the sky"; and λόγος, logos, "knowledge") is the interdisciplinary scientific study of the atmosphere that focuses on weather processes and
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Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location.

Human beings have attempted to predict the weather since time immemorial.
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Paleoclimatology (also Palaeoclimatology) is the study of climate change taken on the scale of the entire history of Earth. It uses records from ice sheets, tree rings, sediment, and rocks to determine the past state of the climate system on Earth.
..... Read more.

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