Assessment of the water and energy budget in a peatland catchment of the Alps using the process based GEOtop hydrological model

Abstract

Over the millennia, peatlands have sequestered and stored carbon in the form of peat, that today accounts for around 30% of the global soil organic carbon. The peat has formed and accumulated due to the slow decomposition rate of organic matter in waterlogged, anaerobic conditions. The particularly close interdependence of the carbon and water cycles in peatland ecosystems signal the importance of understanding the water cycle to the functioning of peatlands.With this aim, the water and energy cycle of an alpine catchment in Italy, which includes a peatland, was studied using the process-based hydrological model GEOtop and a set of in situ measurements over 4 years (2012–2015). This is a challenging modelling exercise that has not been tried before with GEOtop. The catchment is heterogenous with land covers of peatland, grassland, scree and bare rock in a mountainous area. The GEOtop model was able to replicate the energy and water fluxes measured by an eddy covariance tower located in the peatland as well as the volumetric water content and soil temperature of the peatland accurately over the four years. This study shows that a process-based hydrological model can be used to study the water and energy dynamics of a peatland in a mountainous area.