- is the pattern of variation in temperature, humidity, atmospheric pressure, wind,
precipitation, atmospheric particle count and other meteorological variables in a given region over long periods. Climate can be contrasted to
weather, which is the present condition of these variables over shorter periods.
- generally refers to day-to-day temperature and precipitation activity, whereas
climate is the term for the average atmospheric conditions over longer periods of time.
The atmosphere of Earth
- is a layer of gases surrounding the planet Earth that is
retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat
retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation).
- in physical geography describes the combined mass of water found on, under, and over
the surface of a planet.
- collectively describes the portions of the Earth’s surface where water is in solid
form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps and ice sheets, and frozen ground (which includes permafrost).
- refers to the solid parts of the Earth and is used along with atmosphere, hydrosphere,
and biosphere to describe the systems of the Earth (the interaction of these systems with the heliosphere is sometimes listed). In that context,
sometimes the term lithosphere is used instead of geosphere. However, the lithosphere only refers to the uppermost layers of the solid Earth (oceanic
and continental crustal rocks and uppermost mantle).
- is the global sum of all ecosystems. It can also be called the zone of life on Earth, a
closed (apart from solar and cosmic radiation and heat from the interior of the Earth), and self-regulating system. From the broadest
biophysiological point of view, the biosphere is the global ecological system integrating all living beings and their relationships, including their
interaction with the elements of the lithosphere, hydrosphere, and atmosphere.
- or climate cycle is any recurring cyclical oscillation within global
or regional climate, and is a type of climate pattern. These fluctuations in atmospheric temperature, sea surface temperature, precipitation or other
parameters can be quasi-periodic, often occurring on inter-annual, multi-annual, decadal, multidecadal, century-wide, millennial or longer timescales.
A prominent example is the El Niño-Southern Oscillation, involving sea surface temperatures along a stretch of the equatorial Central and East
Pacific Ocean and the western coast of tropical South America, but which affects climate worldwide.
- or El Niño/La Niña–Southern Oscillation, is a band of anomalously warm ocean water
temperatures that occasionally develops off the western coast of South America and can cause climatic changes across the Pacific Ocean. The 'Southern
Oscillation' refers to variations in the temperature of the surface of the tropical eastern Pacific Ocean (warming and cooling known as El Niño and
La Niña, respectively) and in air surface pressure in the tropical western Pacific.
The accepted definition is a warming or cooling of at least 0.5°C (0.9°F) averaged over the east-central tropical Pacific Ocean. Typically, this
anomaly happens at irregular intervals of two to seven years, and lasts nine months to two years. The average period length is five years. When this
warming or cooling occurs for only seven to nine months, it is classified as El Niño/La Niña "conditions"; when it occurs for more than that
period, it is classified as El Niño/La Niña "episodes".
Pacific Decadal Oscillation
- (PDO) is a pattern of change in the Pacific Ocean's
climate. The PDO is detected as warm or cool surface waters in the Pacific Ocean, north of 20° N. During a "warm", or "positive", phase, the west
Pacific becomes cool and part of the eastern ocean warms; during a "cool" or "negative" phase, the opposite pattern occurs.
It shifts phases on at least inter-decadal time scale, usually about 20 to 30 years.
Atlantic Multidecadal Oscillation
- (AMO) is a mode of variability
occurring in the North Atlantic Ocean and which has its principal expression in the sea surface temperature (SST) field. While there is some support
for this mode in models and in historical observations, controversy exists with regard to its amplitude, and in particular, the attribution of sea
surface temperature change to natural or anthropogenic causes, especially in tropical Atlantic areas important for hurricane development.
- (AO) or Northern Annular Mode/Northern Hemisphere Annular Mode (NAM)
is an index (which varies over time with no particular periodicity) of the dominant pattern of non-seasonal sea-level pressure variations north of 20N
latitude, and it is characterized by pressure anomalies of one sign in the Arctic with the opposite anomalies centered about 37–45N. The AO is
believed by climatologists to be causally related to, and thus partially predictive of, weather patterns in locations many thousands of miles away,
including many of the major population centers of Europe and North America.
- Records of global average
surface temperature are usually presented as anomalies rather than as absolute temperatures. A temperature anomaly is measured against a reference
value or long-term average.
Absolute temperatures for the Earth's average surface temperature have been derived, with a best estimate of roughly 14 °C (57.2 °F). However, the
correct temperature could easily be anywhere between 13.3 and 14.4°C (56 and 58 °F) and uncertainty increases at smaller (non-global) scales.
- (also known as one of the classes of hydrometeors, which are atmospheric water
phenomena) is any product of the condensation of atmospheric water vapour that falls under gravity. The main forms of precipitation include drizzle,
rain, sleet, snow, graupel and hail. Precipitation occurs when a local portion of the atmosphere becomes saturated with water vapour, so that the
water condenses and "precipitates".
- is the large-scale movement of air, and the means (together
with the smaller ocean circulation) by which thermal energy is distributed on the surface of the Earth.
The large-scale structure of the atmospheric circulation varies from year to year, but the basic climatological structure remains fairly constant.