Decadal water balance of a temperate Scots pine forest (Pinus sylvestris L.) based on measurements and modelling

[摘要] We examined the water balance components of an 80-year-old Scots pine(Pinus sylvestris L.) forest stand in the Campine region of Belgium over a ten year periodusing five very different approaches; our methods ranged from data intensivemeasurements to process model simulations. Specifically, we used theconservative ion method (CI), the Eddy Covariance technique (EC), anempirical model (WATBAL), and two process models that vary greatly in theirtemporal and spatial scaling, the ORCHIDEE global land-surface model andSECRETS a stand- to ecosystem-scale biogeochemical process model. Herein weused the EC technique as a standard for the evapotranspiration (ET)estimates. Using and evaluating process based models with data is extremelyuseful as models are the primary method for integration of small-scale,process level phenomena into comprehensive description of forest stand orecosystem function. Results demonstrated that the two process modelscorresponded well to the seasonal patterns and yearly totals of ET from theEC approach. However, both WATBAL and CI approaches overestimated ET whencompared to the EC estimates. We found significant relationships betweenseveral meteorological variables (i.e., vapour pressure deficit [VPD], meanair temperature [T_air], and global radiation [Rg]) and ET on monthly basisfor all approaches. In contrast, few relationships were significant onannual basis. Independent of the method examined, ET exhibited lowinter-annual variability. Consequently, drainage fluxes were highlycorrelated with annual precipitation for all approaches examined, except CI.

[学科分类] 地球化学与岩石