## 2.24.4. Peat fires[¶](#peat-fires "Permalink to this headline")
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The burned area due to peat fires is given as \\({A}\_{b}\\):

(2.24.37)[¶](#equation-23-37 "Permalink to this equation")\\\[A\_{b} = c \\ f\_{cli,p} f\_{peat} (1 - f\_{sat} ) A\_{g}\\\]

where \\(c\\) (s\-1) is a constant; \\(f\_{cli,p}\\) represents the effect of climate on the burned area; \\(f\_{peat}\\) is the fractional coverage of peatland in the grid cell; and \\(f\_{sat}\\) is the fraction of the grid cell with a water table at the surface or higher. \\(c\\) = 0.17 \\(\\times\\) 10 \-3 hr\-1 for tropical peat fires and \\(c\\) = 0.9 \\(\\times\\) 10 \-5 hr \-1 for boreal peat fires are derived using an inverse method, by matching simulations to earlier studies: about 2.4 Mha peatland was burned over Indonesia in 1997 ([Page et al. 2002](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#pageetal2002)) and the average burned area of peat fires in Western Canada was 0.2 Mha yr \-1 for 1980-1999 ([Turetsky et al. 2004](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#turetskyetal2004)).

For tropical peat fires, \\(f\_{cli,p}\\) is set as a function of long-term precipitation \\(P\_{60d}\\) :

(2.24.38)[¶](#equation-23-38 "Permalink to this equation")\\\[f\_{cli,p} = \\ max \\left\[0,\\min \\left(1,\\frac{4-P\_{60d} }{4} \\right)\\right\]^{2} .\\\]

For boreal peat fires, \\(f\_{cli,p}\\) is set to

(2.24.39)[¶](#equation-23-39 "Permalink to this equation")\\\[f\_{cli,p} = \\exp (-\\pi \\frac{\\theta \_{17cm} }{0.3} )\\cdot \\max \[0,\\min (1,\\frac{T\_{17cm} -T\_{f} }{10} )\]\\\]

where \\(\\theta \_{17cm}\\) is the wetness of the top 17 cm of soil.

Peat fires lead to peat burning and the combustion and mortality of vegetation over peatlands. For tropical peat fires, based on [Page et al. (2002)](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#pageetal2002), about 6% of the peat carbon loss from stored carbon is caused by 33.9% of the peatland burned. Carbon emissions due to peat burning (g C m\-2 s\-1) are therefore set as the product of 6%/33.9%, burned area fraction of peat fire (s\-1), and soil organic carbon (g C m\-2). For boreal peat fires, the carbon emissions due to peat burning are set as 2.2 kg C m\-2 peat fire area ([Turetsky et al. 2002](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/References/CLM50_Tech_Note_References.html#turetskyetal2002)). Biomass combustion and vegetation mortality in post-fire peatlands are set the same as section [2.24.1.3](#fire-impact) for non-crop PFTs and as section [2.24.2](#agricultural-fires) for crops PFTs.

