Use of BIOME-BGC to simulate water and carbon fluxes within Mediterranean macchia

The biogeochemical model BIOME-BGC is capable to estimate the main ecophysiological processes characterising all terrestrial ecosystems. To this aim it needs to be properly adapted to reproduce the behaviour of each biome type through a calibration phase. The aim of this paper is to adapt BIOME-BGC to reproduce the evapotranspiration (ET) and photosynthesis (GPP) of Mediterranean macchia spread all over Italy. Ten different sites were selected in the Centre-South of Italy and their gross primary production (GPP) was estimated by applying a parametric model, C-Fix, based on remotely sensed data for ten years (1999-2008). These monthly data were then used to calibrate BIOME-BGC through an iterative process which led to reproduce the spatial and temporal GPP variations found by C-Fix. The calibrated model was then applied to simulate the ET and GPP of two Italian sites characterised by the presence of an eddy flux tower; its performances were evaluated against ground data by common statistics. The results obtained indicate that, after a proper calibration phase, BIOME-BGC can be applied to estimate the evapotranspiration and photosynthesis of Mediterranean macchia with a good accuracy, strictly dependent on the input data utilised.