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Below is a picture showing the amount of methane in the atmosphere (3500 Tg = 3500 tons) and the major processes adding methane to and removing methane from the atmosphere. Units are all in metric tons (or 10 6 grams) and metric tons/year of methane. Loss by chemical reaction
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Below is a picture showing the amount of methane in the atmosphere (3500 Tg = 3500 tons) and the major processes adding methane to and removing methane from the atmosphere. Units are all in metric tons (or 106 grams) and metric tons/year of methane Loss by chemical reaction 520 TONS/YR -57 per mil 0.8 Methane in atmosphere 4680tons Natural wetlands tons/yr W -65 per mil 1.0 https://webfiles.uci.edu/setrumbo/public/IMPRS/fossil%20fuels.xls?uniq=-1o7yls Fossil fuel associated emissions tons/yr F -40 per mill 0 Biomass burning tons/yr B -20 per mil 1.0 W+B+F = 520 W*(-65) +B(-20) + F*(-40) = 520*(-57) W*1.0 + B(1.0) +F*0 = 520*0.8
V = volume of air in hemispehre (assume equal in N, S) Xn, Xs = mixing ratio of CO2 in N, S (assume 315 in 1958) Rate of exchange between hemispheres is V/1yr For F, B see spreadsheet Northern hemisphere Southern hemisphere VXn VXs F fossil fuel) B/2 S B/2 S https://webfiles.uci.edu/setrumbo/public/IMPRS VdXs (t)/dt =VXn(t-1)/1yr +B/2 – S VdsXn (t)/dt = VXs(t-1)/1yr +B/2 –S +F S+S =(1- 0.57)F = 0.43 F VdXn/dt + VdXs/dt = 0.57F Moles air in atmosphere =2V = [1.78 x 10^20] Moles CO2 in air in 1950 = 315 x 10^-6 * 1.78 x 10^20 moles
