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Steady State Analysis
AOSC 620
Fall 2015
Definition: Steady State – the condition where the concentration of a substance is unchanging in time. This implies that the production and loss rates are equal.
A system in thermodynamic equilibrium is necessarily in steady state , but a system in steady state is not necessarily in thermodynamic equilibrium.
More interesting is the occurrence of quasi-steady state – where the overall rate of change is small compared with the production and loss terms. This applies to many atmospheric and oceanic species of importance to climate.
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2. Copyright © 2009 R.R. Dickerson
The first theoretical derivation of quasi-steady state appears in Global Biogeochemical Cycles in an article by Cicerone and Oremland (1988).
Consider a gas in the atmosphere with a mixing ratio that varies in time and space:
[ ] = f(x, y, z, t)
And the molecular number density is
M = f((x, y, z, t).
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[O]ss = j1[NO2]/k2[O2][M]
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We’ll see where this comes from later.
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