On the influence of peatland draining on local climate

In no other country has the draining of peatland taken place to such a large extent as in Finland. According to earlier studies based on an analysis of observed temperatures, this draining has lowered the night-time minimum temperatures in heavily-drained regions. In the present study, we simulated the cooling effect using the HIRLAM numerical weather prediction model. When simulated wet and dry peat conditions were compared in a late summer clear and calm case leading to night frost, the drop in local night-time minimum temperatures reached ten degrees. The difference in temperature was caused mainly by the change in the soil heat flux.