Editing Climate model (section)

==Box models==
[[File:Simple box model.png|thumb|upright=1|right| Schematic of a simple box model used to illustrate [[flux]]es in geochemical cycles, showing a source ''(Q)'', sink ''(S)'' and reservoir ''(M)'']]

Box models are simplified versions of complex systems, reducing them to boxes (or [[Thermodynamics#Instrumentation|reservoir]]s) linked by fluxes. The boxes are assumed to be mixed homogeneously. Within a given box, the concentration of any [[chemical species]] is therefore uniform. However, the abundance of a species within a given box may vary as a function of time due to the input to (or loss from) the box or due to the production, consumption or decay of this species within the box.{{cn|date=April 2023}}

Simple box models, i.e. box model with a small number of boxes whose properties (e.g. their volume) do not change with time, are often useful to derive analytical formulas describing the dynamics and steady-state abundance of a species. More complex box models are usually solved using numerical techniques.{{cn|date=April 2023}}

Box models are used extensively to model environmental systems or ecosystems and in studies of [[ocean circulation]] and the [[carbon cycle]].<ref name="Sarmiento1984">{{cite journal |author=Sarmiento, J.L. |author2=Toggweiler, J.R. |year=1984 |title=A new model for the role of the oceans in determining atmospheric P CO 2 |journal=Nature |volume=308 |issue=5960 |pages=621–24 |bibcode=1984Natur.308..621S |doi=10.1038/308621a0 |s2cid=4312683}}</ref>
They are instances of a [[multi-compartment model]].

In 1961 [[Henry Stommel]] was the first to use a simple [[Multiple equilibria in the Atlantic meridional overturning circulation#Stommel box model|2-box model]] to study factors that influence ocean circulation.<ref>{{Cite journal|last=Stommel|first=Henry|date=May 1961|title=Thermohaline Convection with Two Stable Regimes of Flow|url=https://www.tandfonline.com/doi/abs/10.3402/tellusa.v13i2.9491|journal=Tellus|volume=13|issue=2|pages=224–230|doi=10.3402/tellusa.v13i2.9491|doi-access=free|issn=0040-2826}}</ref>