Climate
From Wikipedia, the free encyclopedia
Climate (from ancient Greek: κλίμα, "Clime") is commonly defined as the weather averaged over a long period of time. For practical uses the standard averaging period is 30 years, but other periods may be used depending on the purpose.
In scientific usage "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]
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Climatology [cat.]
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[edit] Classifications
In the original Greek sense, 'Clime,' was a concept used to divide the world into climatic zones sharing similar climatic attributes such as temperature, length of the solar day (sunlight), and in particular latitudinal distance from the equator. Modern data and analysis show that the latitudinal concepts of antiquity are too simplistic. Instead, the latitudinal trend is altered by such features as hills or mountain ranges, large lakes, and seas or oceans.
Consequently, today's climate regions are classified on the basis of temperature and precipitation alone. The most commonly used classification is the Köppen classification system, which divides Earth's climates into five (sometimes six) primary classifications and numerous subclassifications. and the Thornthwaite climate classification. In broad terms, climate zones range in latitude from tropical (hot, no real seasons based on temperature) to mid-latitude (moderate; conventional winter-spring-summer-autumn seasons) to polar (cold; strong seasonality; long winters). They also divide into Continental (high contrast between summer and winter) and Maritime (ocean influence moderates temperature extremes, but generally contribute extra moisture to local weather patterns). The mid-latitude 'conventional four seasons' only work well in the mid-latitudes. In other regions the more useful divide is into "wet" and "dry" seasons based on the monsoon.
- For more details about specific climates, see
- Tropical climate
- Subtropical climate
- Arid climate
- Semiarid climate
- Mediterranean climate
- Temperate climate
- Oceanic climate
- Continental climate
- Alpine climate
- Subarctic climate
- Polar climate
- Climate of Antarctica
For the climate of a specific place or area, see the article on that place or area.
[edit] Climate determinants
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 in so far as the determinants of historical climate change are concerned.
[edit] Climate indices
Scientists use climate indices in their attempt to characterize and understand the various climate mechanisms that culminate in our daily weather. Much in the way the Dow Jones Industrial Average, which is based on the stock prices of 30 companies, is used to represent the fluctuations in the stock market as a whole, climate indices are used to represent the essential elements of climate. Climate indices are generally devised with the twin objectives of simplicity and completeness, and each index typically represents the status and timing of the climate factor it represents. By their very nature, indices are simple, and combine many details into a generalized, overall description of the atmosphere or ocean which can be used to characterize the factors which impact the global climate system.
[edit] Historical climates
[edit] National and regional climates
[edit] See also
- Air conditioning
- Climate change
- Climateprediction.net - a distributed computing project (using, amongst others, BOINC) to try and produce a forecast of the climate in the 21st century Website
- Biome - an ecological term for a major regional group of distinctive plant and animal communities best adapted to the region's physical environment
- Effect of sun angle on climate
- Electronic Climate Control
- Solar variation
- Temperature extreme
[edit] External links
- IFAS AgClimate
- Climate Prediction Project
- WorldClimate
- ESPERE Climate Encyclopaedia
- Extreme Temperatures Around the World-Historical Records
- Weatherbase
- Global Climate Data
- Climate index and mode information
- Why and how do scientists study climate change in the Arctic? What are the Arctic climate indices?
- A near-realtime Arctic Change Indicator Website
- A current view of the Bering Sea Ecosystem and Climate
- Climate charts for USA and global locations
- World climates list and articles
[edit] Notes
| Climate types under the Köppen climate classification |
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| Class A: Tropical (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) |
