Climatology (from

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

, ''klima'', "slope"; and , ''

-logia ''-logy'' is a suffix in the English language, used with words originally adapted from Ancient Greek ending in ('). The earliest English examples were anglicizations of the French '' -logie'', which was in turn inherited from the Latin '' -lo ...

'') or climate science is the scientific study of Earth's

climate Climate is the long-term weather pattern in a region, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteoro ...

, typically defined as weather conditions averaged over a period of at least 30 years. Climate concerns the atmospheric condition during an extended to indefinite period of time; weather is the condition of the atmosphere during a relative brief period of time. The main topics of research are the study of

climate variability Climate variability includes all the variations in the climate that last longer than individual weather events, whereas the term climate change only refers to those variations that persist for a longer period of time, typically decades or more ...

, mechanisms of climate changes and

modern climate change Present-day climate change includes both global warming—the ongoing increase in global average temperature—and its wider effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes ...

. This topic of study is regarded as part of the

atmospheric sciences Atmospheric science is the study of the Earth's atmosphere and its various inner-working physical processes. Meteorology includes atmospheric chemistry and atmospheric physics with a major focus on weather forecasting. Climatology is the study ...

and a subdivision of

physical geography Physical geography (also known as physiography) is one of the three main branches of geography. Physical geography is the branch of natural science which deals with the processes and patterns in the natural environment such as the atmosphere, h ...

, which is one of the

Earth science Earth science or geoscience includes all fields of natural science related to the planet Earth. This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four spheres ...

s. Climatology includes some aspects of

oceanography Oceanography (), also known as oceanology, sea science, ocean science, and marine science, is the scientific study of the ocean, including its physics, chemistry, biology, and geology. It is an Earth science, which covers a wide range of to ...

and

biogeochemistry Biogeochemistry is the Branches of science, scientific discipline that involves the study of the chemistry, chemical, physics, physical, geology, geological, and biology, biological processes and reactions that govern the composition of the natu ...

. The main methods employed by climatologists are the analysis of observations and modelling of the physical processes that determine climate. Short term

weather forecasting Weather forecasting or weather prediction is the application of science and technology forecasting, to predict the conditions of the Earth's atmosphere, atmosphere for a given location and time. People have attempted to predict the weather info ...

can be interpreted in terms of knowledge of longer-term phenomena of climate, for instance climatic cycles such as the

El Niño–Southern Oscillation El Niño–Southern Oscillation (ENSO) is a global climate phenomenon that emerges from variation in winds and sea surface temperatures over the tropical Pacific Ocean. Those variations have an irregular pattern but do have some semblance of cyc ...

(ENSO), the Madden–Julian oscillation (MJO), the North Atlantic oscillation (NAO), the

Arctic oscillation The Arctic oscillation (AO) or Northern Annular Mode/Northern Hemisphere Annular Mode (NAM) is a weather phenomenon at the Arctic pole north of 55 degrees latitude. It is an important mode of climate variability for the Northern Hemisphere. The s ...

(AO), the

Pacific decadal oscillation The Pacific decadal oscillation (PDO) is a robust, recurring pattern of ocean-atmosphere climate variability centered over the mid-latitude Pacific basin. The PDO is detected as warm or cool surface waters in the Pacific Ocean, north of 20°N. O ...

(PDO), and the Interdecadal Pacific Oscillation (IPO).

Climate model Numerical climate models (or climate system models) are mathematical models that can simulate the interactions of important drivers of climate. These drivers are the atmosphere, oceans, land surface and ice. Scientists use climate models to st ...

s are used for a variety of purposes from studying the dynamics of the weather and climate system to predictions of future climate.

History

The Greeks began the formal study of climate; in fact, the word "climate" is derived from the Greek word ''klima'', meaning "slope", referring to the slope or inclination of the Earth's axis. Arguably the most influential classic text concerning climate was ''On Airs, Water and Places'' written by

Hippocrates Hippocrates of Kos (; ; ), also known as Hippocrates II, was a Greek physician and philosopher of the Classical Greece, classical period who is considered one of the most outstanding figures in the history of medicine. He is traditionally referr ...

about 400 BCE. This work commented on the effect of climate on human health and cultural differences between Asia and Europe. This idea that climate controls which populations excel depending on their climate, or '' climatic determinism'', remained influential throughout history. Chinese scientist

Shen Kuo Shen Kuo (; 1031–1095) or Shen Gua, courtesy name Cunzhong (存中) and Art name#China, pseudonym Mengqi (now usually given as Mengxi) Weng (夢溪翁),Yao (2003), 544. was a Chinese polymath, scientist, and statesman of the Song dynasty (960� ...

(1031–1095) inferred that climates naturally shifted over an enormous span of time, after observing

petrified In geology, petrifaction or petrification () is the process by which organic material becomes a fossil through the replacement of the original material and the filling of the original pore spaces with minerals. Petrified wood typifies this proce ...

bamboo Bamboos are a diverse group of mostly evergreen perennial plant, perennial flowering plants making up the subfamily (biology), subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family, in th ...

s found underground near Yanzhou (modern

Yan'an Yan'an; ; Chinese postal romanization, alternatively spelled as Yenan is a prefecture-level city in the Shaanbei region of Shaanxi Province of China, province, China, bordering Shanxi to the east and Gansu to the west. It administers several c ...

Shaanxi Shaanxi is a Provinces of China, province in north Northwestern China. It borders the province-level divisions of Inner Mongolia to the north; Shanxi and Henan to the east; Hubei, Chongqing, and Sichuan to the south; and Gansu and Ningxia to t ...

province), a dry-climate area unsuitable at that time for the growth of bamboo. The invention of

thermometer A thermometer is a device that measures temperature (the hotness or coldness of an object) or temperature gradient (the rates of change of temperature in space). A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb ...

s and

barometer A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis ...

s during the

Scientific Revolution The Scientific Revolution was a series of events that marked the emergence of History of science, modern science during the early modern period, when developments in History of mathematics#Mathematics during the Scientific Revolution, mathemati ...

allowed for systematic recordkeeping, that began as early as 1640–1642 in England. Early climate researchers include

Edmund Halley Edmond (or Edmund) Halley (; – ) was an English astronomer, mathematician and physicist. He was the second Astronomer Royal in Britain, succeeding John Flamsteed in 1720. From an observatory he constructed on Saint Helena in 1676–77, H ...

, who published a map of the trade winds in 1686 after a voyage to the southern hemisphere.

Benjamin Franklin Benjamin Franklin (April 17, 1790) was an American polymath: a writer, scientist, inventor, statesman, diplomat, printer, publisher and Political philosophy, political philosopher.#britannica, Encyclopædia Britannica, Wood, 2021 Among the m ...

(1706–1790) first mapped the course of the

Gulf Stream The Gulf Stream is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and flows through the Straits of Florida and up the eastern coastline of the United States, then veers east near 36°N latitude (North Carolin ...

for use in sending mail from North America to Europe.

Francis Galton Sir Francis Galton (; 16 February 1822 – 17 January 1911) was an English polymath and the originator of eugenics during the Victorian era; his ideas later became the basis of behavioural genetics. Galton produced over 340 papers and b ...

(1822–1911) invented the term ''

anticyclone A high-pressure area, high, or anticyclone, is an area near the surface of a planet where the atmospheric pressure is greater than the pressure in the surrounding regions. Highs are middle-scale meteorological features that result from interpl ...

''.

Helmut Landsberg Helmut Erich Landsberg (1906–1985) was a noted and influential climatologist. He was born in Frankfurt, Germany, February 9, 1906, and died December 6, 1985, in Geneva, Switzerland while attending a meeting of the World Meteorological Orga ...

(1906–1985) fostered the use of

statistical analysis Statistical inference is the process of using data analysis to infer properties of an underlying probability distribution.Upton, G., Cook, I. (2008) ''Oxford Dictionary of Statistics'', OUP. . Inferential statistical analysis infers properties of ...

in climatology. During the early 20th century, climatology mostly emphasized the description of regional climates. This descriptive climatology was mainly an applied science, giving farmers and other interested people statistics about what the normal weather was and how great chances were of extreme events. To do this, climatologists had to define a ''

climate normal Climatological normal or climate normal (CN) is a 30-year average of a weather variable for a given time of year.weather extremes over a period of typically 30 years. While scientists knew of past climate change such as the

ice ages An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and Gre ...

, the concept of climate as changing only very gradually was useful for descriptive climatology. This started to change during the decades that followed, and while the history of climate change science started earlier, climate change only became one of the main topics of study for climatologists during the 1970s and afterward.

Subfields

Various subtopics of climatology study different aspects of climate. There are different categorizations of the sub-topics of climatology. The

American Meteorological Society The American Meteorological Society (AMS) is a scientific and professional organization in the United States promoting and disseminating information about the atmospheric, oceanic, and hydrologic sciences. Its mission is to advance the atmosph ...

for instance identifies descriptive climatology, scientific climatology and applied climatology as the three subcategories of climatology, a categorization based on the complexity and the purpose of the research. Applied climatologists apply their expertise to different industries such as

manufacturing Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of the secondary sector of the economy. The term may refer ...

and

agriculture Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...

Paleoclimatology Paleoclimatology ( British spelling, palaeoclimatology) is the scientific study of climates predating the invention of meteorological instruments, when no direct measurement data were available. As instrumental records only span a tiny part of ...

is the attempt to reconstruct and understand past climates by examining records such as

ice cores An ice core is a core sample that is typically removed from an ice sheet or a high mountain glacier. Since the ice forms from the incremental buildup of annual layers of snow, lower layers are older than upper ones, and an ice core contains i ...

and tree rings (

dendroclimatology Dendroclimatology is the science of determining past climates from trees (primarily properties of the annual tree rings). Tree rings are wider when conditions favor growth, narrower when times are difficult. Other properties of the annual rings, ...

). Paleotempestology uses these same records to help determine hurricane frequency over millennia. Historical climatology is the study of climate as related to human history and is thus concerned mainly with the last few thousand years. Boundary-layer climatology concerns exchanges in water, energy and momentum near surfaces. Further identified subtopics are physical climatology, dynamic climatology,

tornado climatology Tornadoes have been recorded on all continents except Antarctica. They are most common in the middle latitudes where conditions are often favorable for convective storm development. The United States has the most tornadoes of any country, as we ...

, regional climatology,

bioclimatology Bioclimatology is the Interdisciplinarity, interdisciplinary field of science that studies the interactions between the biosphere and the Earth's atmosphere on time scales of the order of seasons or longer (in contrast to biometeorology). Examples ...

, and synoptic climatology. The study of the

hydrological cycle The water cycle (or hydrologic cycle or hydrological cycle) is a biogeochemical cycle that involves the continuous movement of water on, above and below the surface of the Earth across different reservoirs. The mass of water on Earth remains fai ...

over long time scales is sometimes termed hydroclimatology, in particular when studying the effects of climate change on the water cycle.

Methods

The study of contemporary climates incorporates meteorological data accumulated over many years, such as records of rainfall, temperature and atmospheric composition. Knowledge of the atmosphere and its dynamics is also embodied in

models A model is an informative representation of an object, person, or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin , . Models can be divided int ...

, either

statistical Statistics (from German language, German: ', "description of a State (polity), state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a s ...

mathematical Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...

, which help by integrating different observations and testing how well they match. Modeling is used for understanding past, present and potential future climates. Climate research is made difficult by the large scale, long time periods, and complex processes which govern climate. Climate is governed by physical principles which can be expressed as differential equations. These equations are coupled and nonlinear, so that approximate solutions are obtained by using numerical methods to create

global climate model A general circulation model (GCM) is a type of climate model. It employs a mathematical model of the general circulation of a planetary atmosphere or ocean. It uses the Navier–Stokes equations on a rotating sphere with thermodynamics, thermod ...

s. Climate is sometimes modeled as a

stochastic process In probability theory and related fields, a stochastic () or random process is a mathematical object usually defined as a family of random variables in a probability space, where the index of the family often has the interpretation of time. Sto ...

but this is generally accepted as an approximation to processes that are otherwise too complicated to analyze.

Climate data

The collection of a long record of climate variables is essential for the study of climate. Climatology deals with the aggregate data that meteorologists have recorded. Scientists use both direct and indirect observations of the climate, from Earth observing satellites and scientific instrumentation such as a global network of

s, to

prehistoric Prehistory, also called pre-literary history, is the period of human history between the first known use of stone tools by hominins million years ago and the beginning of recorded history with the invention of writing systems. The use o ...

ice extracted from

glacier A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

s. As measuring technology changes over time, records of data often cannot be compared directly. As cities are generally warmer than the areas surrounding,

urbanization Urbanization (or urbanisation in British English) is the population shift from Rural area, rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. ...

has made it necessary to constantly correct data for this

urban heat island Urban areas usually experience the urban heat island (UHI) effect; that is, they are significantly warmer than surrounding rural areas. The temperature difference is usually larger at night than during the day, and is most apparent when winds ar ...

effect.

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 of the average temperature of the Earth. Most climate models include the radiative effects of

greenhouse gas Greenhouse gases (GHGs) are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. Unlike other gases, greenhouse gases absorb the radiations that a planet emits, resulting in the greenhouse effect. T ...

es such as

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

. These models predict a trend of increase of surface temperatures, as well as a more rapid increase of temperature at higher latitudes. Models can range from relatively simple to 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. * Coupled atmosphere–ocean–

sea ice Sea ice arises as seawater freezes. Because ice is less density, dense than water, it floats on the ocean's surface (as does fresh water ice). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world' ...

global climate models discretise and solve the full equations for mass and energy transfer and radiant exchange. * Earth system models further include the biosphere. Additionally, they are available with different resolutions ranging from >100 km to 1 km. High resolutions in global climate models are computational very demanding and only few global datasets exists. Examples are ICON or mechanistically downscaled data such as CHELSA (Climatologies at high resolution for the Earth's land surface areas).

Topics of research

Topics that climatologists study comprise three main categories:

, mechanisms of climatic change, and modern changes of climate.

Climatological processes

Various factors affect the average state of the atmosphere at a particular location. For instance, midlatitudes will have a pronounced seasonal cycle of temperature whereas

tropical regions The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

show little variation of temperature over a year. Another major variable of climate is continentality: the distance to major water bodies such as

ocean The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as ''oceans'' (the Pacific, Atlantic, Indian Ocean, Indian, Southern Ocean ...

s. Oceans act as a moderating factor, so that land close to it has typically less difference of temperature between

winter Winter is the coldest and darkest season of the year in temperate and polar climates. It occurs after autumn and before spring. The tilt of Earth's axis causes seasons; winter occurs when a hemisphere is oriented away from the Sun. Dif ...

and summer than areas further from it. The atmosphere interacts with other parts of the

climate system Earth's climate system is a complex system with five interacting components: the Atmosphere of Earth, atmosphere (air), the hydrosphere (water), the cryosphere (ice and permafrost), the lithosphere (earth's upper rocky layer) and the biosphere ( ...

, with winds generating

ocean current An ocean current is a continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, sh ...

s that transport heat around the globe.

Climate classification

Classification is an important method of simplifying complicated processes. Different

climate classification Climate zones are systems that categorize the world's climates. A climate classification may correlate closely with a biome classification, as climate is a major influence on life in a region. The most used is the Köppen climate classification ...

s have been developed over the centuries, with the first ones in

Ancient Greece Ancient Greece () was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity (), that comprised a loose collection of culturally and linguistically r ...

. How climates are classified depends on what the application is. A

wind energy Wind power is the use of wind energy to generate useful work. Historically, wind power was used by sails, windmills and windpumps, but today it is mostly used to generate electricity. This article deals only with wind power for electricity ...

producer will require different information (wind) in a classification than someone more interested in agriculture, for whom precipitation and temperature are more important. The most widely used classification, the

Köppen climate classification The Köppen climate classification divides Earth climates into five main climate groups, with each group being divided based on patterns of seasonal precipitation and temperature. The five main groups are ''A'' (tropical), ''B'' (arid), ''C'' (te ...

, was developed during the late nineteenth century and is based on vegetation. It uses monthly data concerning temperature and

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwe ...

Climate variability

There are different types of variability: recurring patterns of temperature or other climate variables. They are quantified with different indices. Much in the way the

Dow Jones Industrial Average The Dow Jones Industrial Average (DJIA), Dow Jones, or simply the Dow (), is a stock market index of 30 prominent companies listed on stock exchanges in the United States. The DJIA is one of the oldest and most commonly followed equity indice ...

, which is based on the stock prices of 30 companies, is used to represent the fluctuations of stock prices in general, 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 effect the global climate system.

(ENSO) is a coupled ocean-atmosphere phenomenon in the Pacific Ocean responsible for much of the global variability of temperature, and has a cycle between two and seven years. The North Atlantic oscillation is a mode of variability that is mainly contained to the lower atmosphere, the

troposphere The troposphere is the lowest layer of the atmosphere of Earth. It contains 80% of the total mass of the Atmosphere, planetary atmosphere and 99% of the total mass of water vapor and aerosols, and is where most weather phenomena occur. From the ...

. The layer of atmosphere above, the

stratosphere The stratosphere () is the second-lowest layer of the atmosphere of Earth, located above the troposphere and below the mesosphere. The stratosphere is composed of stratified temperature zones, with the warmer layers of air located higher ...

is also capable of creating its own variability, most importantly the Madden–Julian oscillation (MJO), which has a cycle of approximately 30 to 60 days. The Interdecadal Pacific oscillation can create changes in the Pacific Ocean and lower atmosphere on decadal time scales.

Climate change

Climate change occurs when changes of Earth's

result in new

weather Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloud cover, cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmo ...

patterns that remain for an extended period of time. This duration of time can be as brief as a few decades to as long as millions of years. The climate system receives nearly all of its energy from the sun. The climate system also gives off energy to outer space. The balance of incoming and outgoing energy, and the passage of the energy through the climate system, determines

Earth's energy budget Earth's energy budget (or Earth's energy balance) is the balance between the energy that Earth receives from the Sun and the energy the Earth loses back into outer space. Smaller energy sources, such as Earth's internal heat, are taken into con ...

. When the incoming energy is greater than the outgoing energy, earth's energy budget is positive and the climate system is warming. If more energy goes out, the energy budget is negative and earth experiences cooling. Climate change also influences the average

sea level Mean sea level (MSL, often shortened to sea level) is an mean, average surface level of one or more among Earth's coastal Body of water, bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical ...

Modern climate change Present-day climate change includes both global warming—the ongoing increase in global average temperature—and its wider effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes ...

is caused largely by the human emissions of

from the burning of fossil fuel which increases global mean surface temperatures. Increasing temperature is only one aspect of modern climate change, which also includes observed changes of

storm track ''Storm Track'' was the first magazine for and about storm chasing. The magazine was in circulation between 1977 and 2002. History and profile ''Storm Track'' was started in 1977 by chasing pioneer David K. Hoadley, David Hoadley following an ...

s and cloudiness. Warmer temperatures are causing further changes of the

, such as the widespread melt of glaciers,

sea level rise The sea level has been rising from the end of the last ice age, which was around 20,000 years ago. Between 1901 and 2018, the average sea level rose by , with an increase of per year since the 1970s. This was faster than the sea level had e ...

and shifts of flora and fauna.

Differences with meteorology

In contrast to

meteorology Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agricultur ...

, which emphasises short term

systems lasting no more than a few weeks, climatology studies the frequency and trends of those systems. It studies the periodicity of weather events over years to millennia, as well as changes of long-term average weather patterns in relation to atmospheric conditions. Climatologists study both the nature of climates – local, regional or global – and the natural or human-induced factors that cause climates to change. Climatology considers the past and can help predict future

climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

. Phenomena of climatological interest include the atmospheric boundary layer, circulation patterns,

heat transfer Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, ...

( radiative,

convective Convection is single or multiphase fluid flow that occurs spontaneously through the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convec ...

and latent), interactions between the atmosphere and the oceans and land surface (particularly vegetation,

land use Land use is an umbrella term to describe what happens on a parcel of land. It concerns the benefits derived from using the land, and also the land management actions that humans carry out there. The following categories are used for land use: fo ...

and

topography Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the landforms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary sci ...

), and the chemical and physical composition of the atmosphere.

Use in weather forecasting

A relative difficult method of forecast, the analog technique requires remembering a previous weather event which is expected to be mimicked by an upcoming event. What makes it a difficult technique is that there is rarely a perfect analog for an event of the future. Some refer to this type of forecasting as pattern recognition, which remains a useful method of estimating rainfall over data voids such as oceans using knowledge of how satellite imagery relates to precipitation rates over land, as well as the forecasting of precipitation amounts and distribution of the future. A variation of this theme, used for medium range forecasting, is known as teleconnections, when systems in other locations are used to help determine the location of a system within the regime surrounding. One method of using teleconnections are by using climate indices such as ENSO-related phenomena.Thinkquest.org
Teleconnections: Linking El Niño with Other Places.
Retrieved on 16 February 2007.

References

Books

* * * *

External links

Climate Science Special Report
– U.S. Global Change Research Program
KNMI Climate Explorer
The Royal Netherlands Meteorological Institute's Climate Explorer graphs climatological relationships of spatial and temporal data.

Amer. Inst. of Physics account of the history of the discipline of climatology in the 20th century {{Authority control Atmospheric sciences Climate and weather statistics Natural environment