Modeling of microscale variations in methane fluxes Anu Kettunen Jan 17th, 2003
2 Solar energy and cycling of elements
3 Natural green house phenomenon Atmosphere surface temperature of Earth ca 30 o C higher than without atmosphere Green house gases prevent Solar energy from escaping from Earth H 2 O, CO 2, CH 4, N 2 O, CFC compounds
4 Human activities Use of fossil fuel etc. human actions increase green house gas concentrations = enhances green house phenomenon climate change Robert T. Watson, IPCC chair
5 Future climate On average warmer Regional differences Precipitation patterns Likelihood for extreme events (drought, storms) increases
6 Mires Northern mires carbon sinks during last millenia, huge amount of carbon in peat Sources of green house gases (CO 2 ja CH 4 ) Important to understand role of mires in carbon cycle
7 Methane CH 4 important green house gas Concentration increases ca 1% per year Wetlands (20-30 %), rice paddies, ruminants, landfills, artificial lakes
8 Research problem Previously no satisfactory description of spatial and seasonal variations in methane fluxes Growing season measurument: CH 4, T, WT etc. from different mire surfaces Methane production and oxidaton potentials Process model connects methane flux to vegetation cover, photosynthetic cycle and peat thermal and moisture conditions
9 Process model
10 Model predictions
11 Fresh carbon, NPP and T Model sensitive to fresh carbon If T ja CO 2 NPP substrate CH 4 If only T CH 4 less
12 Transport of oxygen to peat The more sedges transport oxygen to peat, the lower the CH 4 flux If methane oxidation CH 4 Change in transport capacity of sedges
13 The effect of drought Long dry periods methanogens CH 4 If > 4-6 week drought, no recovery even after rains come
14 Main contribution of the thesis Simulation model for CH 4 fluxes from different mire surfaces CH 4 fluxes from boreal mires can be predicted under current and future climate Increased understanding Connection to general circulation models