## 2.25.9. Seasonal Inundation[¶](#seasonal-inundation "Permalink to this headline")
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A simple scaling factor is used to mimic the impact of seasonal inundation on CH4 production (see appendix B in [Riley et al. (2011a)](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#rileyetal2011a) for a discussion of this simplified expression):

(2.25.21)[¶](#equation-24-21 "Permalink to this equation")\\\[S=\\frac{\\beta \\left(f-\\bar{f}\\right)+\\bar{f}}{f} ,S\\le 1.\\\]

Here, _f_ is the instantaneous inundated fraction, \\(\\bar{f}\\) is the annual average inundated fraction (evaluated for the previous calendar year) weighted by heterotrophic respiration, and \\(\\beta\\) is the anoxia factor that relates the fully anoxic decomposition rate to the fully oxygen-unlimited decomposition rate, all other conditions being equal.