Editing Climatology (section)

== 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 [[model (abstract)|models]], either [[statistical model|statistical]] or [[mathematical model|mathematical]], 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]]s. Climate is sometimes modeled as a [[stochastic process]] 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.<ref>{{Cite web|url=https://www.climate.gov/maps-data/primer/processing-climate-data|title=How do weather observations become climate data? {{!}} NOAA Climate.gov|website=www.climate.gov|access-date=13 January 2020|archive-date=13 January 2020|archive-url=https://web.archive.org/web/20200113094222/https://www.climate.gov/maps-data/primer/processing-climate-data|url-status=live}}</ref> Scientists use both direct and indirect observations of the climate, from [[Earth observation satellite|Earth observing satellites]] and scientific instrumentation such as a global network of [[thermometer]]s, to [[Prehistory|prehistoric]] ice extracted from [[glacier]]s.<ref>{{Cite web|url=https://climate.nasa.gov/faq/34/what-kinds-of-data-do-scientists-use-to-study-climate|title=What kinds of data do scientists use to study climate?|website=Climate Change: Vital Signs of the Planet|access-date=13 January 2020|archive-date=13 January 2020|archive-url=https://web.archive.org/web/20200113094223/https://climate.nasa.gov/faq/34/what-kinds-of-data-do-scientists-use-to-study-climate/|url-status=live}}</ref> As measuring technology changes over time, records of data often cannot be compared directly. As cities are generally warmer than the areas surrounding, [[urbanization]] has made it necessary to constantly correct data for this [[urban heat island]] effect.{{sfn|Rohli|Vega|2011|p=8}}

=== Models ===
{{Main|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 of the average temperature of the Earth. Most climate models include the radiative effects of [[greenhouse gas]]es such as [[carbon dioxide]]. These models predict a trend of increase of [[Instrumental temperature record|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]] [[General circulation model|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&nbsp;km to 1&nbsp;km. High resolutions in global climate models are computational very demanding and only few global datasets exists. Examples are ICON <ref>{{cite journal |last1=Dipankar |first1=A. |last2=Heinze |first2=Rieke |last3=Moseley |first3=Christopher |last4=Stevens |first4=Bjorn |last5=Zängl |first5=Günther |last6=Brdar |first6=Slavko |title=A Large Eddy Simulation Version of ICON (ICOsahedral Nonhydrostatic): Model Description and Validation |journal=Journal of Advances in Modeling Earth Systems |date=2015 |volume=7}}</ref> or mechanistically downscaled data such as CHELSA (Climatologies at high resolution for the Earth's land surface areas).<ref>{{cite journal |last1=Karger |first1=D.N. |last2=Conrad |first2=O. |last3=Böhner |first3=J. |last4=Kawohl |first4=T. |last5=Kreft |first5=H. |last6=Soria-Auza |first6=R.W. |last7=Zimmermann |first7=N.E. |last8=Linder |first8=P. |last9=Kessler |first9=M. |title=Climatologies at high resolution for the Earth land surface areas |journal=Scientific Data |date=2017 |volume=4 |issue=170122|page=170122 |doi=10.1038/sdata.2017.122|pmid=28872642 |pmc=5584396 }}</ref><ref>{{cite journal |last1=Karger |first1=D.N. |last2=Lange |first2=S. |last3=Hari |first3=C. |last4=Reyer |first4=C.P.O. |last5=Zimmermann |first5=N.E. |title=CHELSA-W5E5 v1.0: W5E5 v1.0 downscaled with CHELSA v2.0 |journal=ISIMIP Repository |date=2021 |doi=10.48364/ISIMIP.836809}}</ref>