Modelling of latent heat partitioning at a bog peatland

Understanding of the surface energy balance is important for predicting climate change effects on carbon cycling in peatlands. Modelling of surface energy fluxes is complicated in these environments because of microscale surface topography, non-vascular moss dynamics, and sparse overstory vegetation; thus traditional ‘big leaf’ approaches do not simulate peatland environments well. Here we adapted a three-source (leaf, hummock, hollow) energy balance model and applied it to energy flux and temperature data from the Mer Bleue bog peatland. Model results show that latent heat flux partitioning into components from the three sources was strongly tied to available energy. The model output suggests that the vascular plants contributed 60–80% of the latent heat flux, hummocks 10–30%, and hollows 10%. These component contributions to latent heat flux showed little variation throughout the study period. It appears that this behaviour resulted from offsetting controls imposed by the vascular plant physiology and moss and peat porosity and capillarity characteristics. Although there was no evidence of strong microadvection between the vascular shrubs and hummock and hollow microtopography, this study highlights the importance of moss in the overall peatland energy fluxes.